# Test/Review of Charger Opus BT-C3100 V2.1



## HKJ

[size=+3]Charger Opus BT-C3100 V2.1[/size]

This is the 3. review of the BT-C3100. Many pictures and text is reused from the first two reviews, but all curves and measurements are new.
This charger briefly shows "2.1" in the display when power is connected.

First review with version 1 software
Update with version 2.0 software















This charger is a analyzing LiIon and NiMH charger, this means the charger can both charge and discharge while measuring. The total number of function is large and this means the technical section in this review is very large.
Note: The top picture is courtesy of Gearbest and is the actual production version of the charger with the Opus logo present.



 






I got the charger in a retail box, but the box is without any brand name.






The only accessory I got was a power supply and a manual. It is a EU version, with universal voltage 100-240VAC 50/60Hz and delivers 12V 3A.






When the charger is turned on, it displays test where all the text can be seen. 
When startup is finished it is possible to select mode:


CHARGE: Charge battery with 200 to 1000 (2000) mA.
DISCHARGE: Discharge battery with 200 to 1000 mA (700 for NiMH).
DISCHARGE REFRESH: Discharge and charge the battery 3 times.
CHARGE TEST: Charge, discharge and charge the battery, show how much current was discharged.
QUICK TEST: Measure the internal resistance of the battery.

When display is flashing it is possible to select mode and current.
Using the slot button it is possible to reselect a slot and change parameters for it, also when charger is working.
When putting multiple batteries in the charger at the same time, it is possible to select mode and current simultaneous for all of them (Very nice).

When charging or discharging it is possible to use the DISPLAY button to select between V, mA and mAh.
The display button can also be used when the charge/discharge is finished, but the charger will change back to "full" display rather quickly.






Here is an example where I have selected different functions for each slot.






Each time a button is pressed, the light turns on for a 20 seconds.
The FULL and NULL message can also be seen.






The charger uses an external 12 volt power supply at 3A.
It has a fan, this is necessary to handle all four channels at full power.
It starts slowly when needed, this makes it much less annoying.









The charger uses the classical slider construction to handle most battery sizes. The slider works smoothly and can handle sizes from 32 mm to 72.5 mm.






A couple of different NiMH batteries in the charger.






And some LiIon batteries.

Using *only* slot #1 and/or #4, the maximum charge current is 2000mA.
In all other cases the maximum charge current is 1000mA.
The maximum discharge current is always 1000mA for LiIon and 700mA for NiMH.

Charge currents: 200, 300, 500, 700, 1000, 1500, 2000
Discharge currents: 200, 300, 500, 700, (1000)






































The charger can easily handle 70 mm long batteries including flat top cells.
It is recommended to charge smaller batteries in the two center slots.
The charger has an internal switch marked with 3.7V, 4.20V and 4.35V. I have not tested this switch, because it is internal, but it might be possible to charge other LiIon chemistries.



[size=+2]Measurements[/size]



The LCD background light turns off 20 seconds after the last keypress.
It Will discharge LiIon batteries with up to 4.1mA when not charging.
Power cycling will restart charging.
Reinsertion of batteries will restart last mode selected.
LiIon charging will restart if the voltage drops to 4.1V
When batteries are put in and no buttons is pressed a 0.5A charge will start.
Voltage is measured with current off and is within 0.01 volt.
Voltage display is updated once every 30 seconds.
When charger is powered on it always starts in charging mode with 0.5A selected.
While power is on it remembers last mode selection, but will always start at 0.5A.
When not connected to power it will drain about 4.3mA from a LiIon battery and 1.4mA from a NiMH battery.
The fan is speed controlled and will slowly increase speed when required.


[size=+1]CHARGE LiIon batteries[/size]






Charging a 18650 cell at 1A, it is a nice simulated CC/CV curve.
The display shows 3024mAh 3:41






The display shows 2713mAh 3:20






The display shows 2764mAh 3:20






The 3 other channels look similar.
The display shows 2803mAh 3:22






Charging LiIon at very low current does also work fine, but slowly.
The display shows 2922mAh 16:21






Because the charger measures voltage with the current off, there will be some overvoltage when charging batteries.
It does not look that good on this 2600mAh cell, but it ends up with 4.20 volt.
The display shows 2430mAh 3:59






A 3400mAh cell looks fine.






What happens with an old very soft (High Ri) battery? Again the voltage goes to high, but compared to the first version of the charger it is much better.






Let’s reduce the charge current. This did improve the charging considerable, now it looks normal and stays within allowable tolerances.






Using a newer battery in slot #1 does work fine.






The 14500 charges fine.
The display shows 791mAh 2:04






2A is no problem, the charger reduces current to get a nice simulated CC/CV curve.
The display shows 2784mAh 2:08






4 batteries at once with full current. This works fine with the updated software versions
The display shows 2697mAh 2834mAh 2759mAh 2792mAh (The curve is for the first value).






Here I tried with the US power supply that showed problems with the V2.0 software. The measurement looks fairly good (Slot #3 & #4 is a bit high).






Same as above, but I am using an my own power supply, notice the green current scale. The charger is using considerable more than 3A from the power supply in spikes.






Same curve as above, but I have removed the "DC input current" from the chart. It can be seen that the charger charges perfectly with 1A and there is not any significant difference between this curve and the one above made with the original power supply.






M1: 35,9°C, M2: 37,8°C, M3: 37,0°C, M4: 34,6°C, M5: 34,9°C, HS1: 40,8°C

The fan is helping keeping the temperature down, batteries are not that hot.






M1: 36,0°C, M2: 37,6°C, M3: 36,8°C, M4: 34,3°C, M5: 37,3°C, HS1: 63,7°C

But something inside the charger is getting warm.






The charger uses pwm to regulate the charge current. The one above is for 0.2A charge.






The pulses are longer at 0.5A










The first version of this charger did have different circuit for slot #1/4 and #2/3, but on the current version they are the same.






At 2A current the current is on most of the time.






From power on to start of charge is about 10 seconds, when no buttons is pressed.






To measure the actual battery voltage the pwm is turned off for about 0.2 seconds every 30 seconds.






The first version of this charger had some nasty 9A current spikes from the power supply, this made the charger show wrong mAh values when charging.
In this version the spikes are reduced to 6A and the charge current is stable, this means the charger can measure correctly.






The power supply can handle the 6A spikes. The voltage drops less than 1 volt.



[size=+1]DISCHARGE LiIon batteries[/size]






The discharge looks nice. It discharges down to 2.9 volt, it is a good value (In my test I uses 2.8 volt).
LiIon batteries are usual rated for 2.5, 2.75 or 3.0 volt discharge, the 3.0 volt type might theoretically be damaged, but I have not seen any in my test to 2.8 volt.
The display shows 2971mAh 2:59














The other 3 channels looks very similar.
Display: 2882mAh, 2942mAh, 2960mAh






With 0.5A the discharge times is double up. Display shows: 2955mAh 5:56






0.2A discharge also looks fine. Display shows: 2920mAh 14:42.






With 4 LiIon at 1A the charger needs to get rid of a lot of heat, i.e. the fan runs at full speed. The fan cools enough to handle it.






M1: 47,7°C, M2: 45,9°C, M3: 43,2°C, M4: 37,2°C, M5: 48,7°C, M6: 29,3°C, HS1: 79,3°C

The resistors for discharging is placed under 3 of the batteries and get fairly hot, this does also warm the batteries.






The discharge does also uses pwm. The high current is because the charger uses the same resistor bank for NiMH and LiIon.










The pwm will be adjusted when the battery voltage drops to maintain a constant current.



[size=+1]DISCHARGE REFRESH LiIon batteries, cycles batteries[/size]






This mode will discharge and charge 3 times. This can be useful for NiMH batteries, but there is really no use for LiIon cells.
The display shows the values from the last charge: 2851mA 3:24


[size=+1]CHARGE TEST LiIon batteries, measure capacity[/size]






To test capacity on batteries the test mode is more useful, it will charge the battery, discharge it and charge it again.



[size=+1]QUICK TEST LiIon batteries, i.e. measuring internal resistance[/size]

I tried with the same LiIon cell in all slots a couple of times:











The result is average for the 5 values and is supposed to match the +XXmOhm value.
Generally the result is very good.






The measuring is done with a short pulse load.



[size=+1]CHARGE NiMH batteries[/size]






Interesting charger curve, it looks like the charger is using a CC/CV algorithm for NiMH batteries. The charger does a good job with the charging. 
Display shows 1915mAh 2:10
Also note that the charger uses trickle charging when the main charge is finished, this is not really a good idea for LSD cells.














The other slots also looks good.






Maximum charge current.
Display shows 1939mAh and 1:09






The temperature raises a bit and then the charger terminates, this is very good.
Display shows 2192mAh and 2:27






Even at a low charge current the charger terminates. 
Display shows: 1821mAh 9:12






A AAA battery does also look fine. 
Display shows 805mAh 2:11






Due to the termination method the charger is not fast at detecting full batteries, but because it uses a low current most of the time it is not hard on the battery.
Display shows 75mAh 0:17






Charging 4 eneloops at the same time looks fine.
Display shows: 1969mAh 1944mAh 1961mAh 1916mAh






When I uses my own 12 volt power supply I do not see any high current draw.






And the charge curve looks fine (Same as above, I have just removed the DC input current trace).






M1: 37,4°C, M2: 38,7°C, M3: 37,3°C, M4: 35,2°C, M5: 35,7°C, M6: 25,8°C, HS1: 44,1°C






Charging is controlled with pwm for NiMH, but the maximum current is less.










With 0.5A and 1A the pulses gets longer.






At 2A charging the current is on most of the time.






Trickle current is also done with pwm, but uses a very short puls.






Startup time is the same for NiMH as LiIon.






The measurement pauses are also the same.



[size=+1]DISCHARGE NiMH batteries[/size]






The charger does a nice 0.7A discharge and stops just below 0.9 volt.
Display shows: 1810mAh 2:36






The 0.2A discharge looks just as fine. 
Display shows: 1814mAh 9:10






M1: 30,6°C, M2: 30,2°C, M3: 29,7°C, M4: 28,0°C, M5: 31,0°C, M6: 25,7°C, HS1: 38,5°C

Handling the heat from discharging NiMH is easy compared to LiIon.






Again pwm to regulate the current.






With full voltage on the battery it is easy to do a 0.7A discharge, when the battery is nearly empty the current will be on most of the time.



[size=+1]DISCHARGE REFRESH NiMH LiIon batteries, cycles batteries[/size]






The refresh function does 3 cycles, this can be used to restore batteries that have been unused for some time.
This function takes a day when run at 0.5A on 2000mAh batteries.



[size=+1]CHARGE TEST NiMH batteries, used to measure capacity[/size]






This function charger, discharges and charges again and is used to measure the capacity of cells.
Display shows: 1892mAh 2:08


[size=+1]QUICK TEST NiMH batteries, i.e. measuring internal resistance[/size]

I tried with the same NiMH cell in all slots a couple of times:











The result is not completely stable, but it does give a good idea about the internal resistance in the battery.






The measuring is done with a short pulse load.



[size=+1]CHARGE with both NiMH and LiIon batteries[/size]

With a charger that can do both eneloop and LiIon it is interesting to see if it has any problem doing them at the same time.






Here I am measuring on the LiIon and it looks very much like a single LiIon, i.e. the NiMH batteries does not affect it.






A eneloop together with 3 LiIon works fine.


Testing with 2500 volt and 5000 volt between mains and low volt side on power supply, did not show any safety problems.



[size=+2]Conclusion[/size]

With this update to the battery analyzer many of the problems has been fixed. 
Generally the peak charge and discharge current for LiIon are a bit high, I would have preferred constant current, instead of the pulsing.
The user interface is fairly easy to use, but it may take a some time to learn what the different modes do.

The conclusion must be that it is a good battery analyzer, but for normal charging I will still prefer a charger with non-pulsing CC/CV charging.



[size=+2]Notes[/size]

When measuring charge current with an oscilloscope I has a 0.1 ohm resistor in series with the battery, this means that the measured currents is lower than reality.

The charger was supplied by Opus for review.

Here is an explanation on how I did the above charge curves: How do I test a charger


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## kreisl

Excellent review, i like it a lot!

Great job, thank you!!


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## RI Chevy

Wow! Very thorough job! :thumbsup:
Thank you Henrik!


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## Chloe

Thanks for the review, HKJ! ^_^


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## realista

so...this 2.1 firmware is almost a DEFINITIVE release?


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## tatasal

realista said:


> so...this 2.1 firmware is almost a DEFINITIVE release?



Yes, the v2.1 is already available at gearbest since last week. Use coupon code btc3100 to drop price down to $45


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## realista

seems that gearbest is the only one partner who sell this charger at DISCOUNT price. so i think first opus batch are for this site/seller


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## candle lamp

Thanks a lot for your excellent test review. HKJ! :thumbsup:


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## Rosoku Chikara

HKJ said:


> ...<Excerpted>
> 
> 
> 
> 
> 
> 
> *The charger has an internal switch marked with 3.7V, 4.20V and 4.35V. I have not tested this switch, because it is internal, but it might be possible to charge other LiIon chemistries.*
> 
> <highlighted>...



Thanks for your many in-depth reviews on this forum. But, I have two questions:

1) How can we find out for sure whether or not this charger can charge LiFePO4?

2) How hard is it to locate and change this "internal switch."

Looking forward to your reply. (Or perhaps someone else has already tested this switch?)


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## HKJ

Rosoku Chikara said:


> 1) How can be find out for sure whether or not this charger can charge LiFePO4?



According to some other reviews I have seen it works.



Rosoku Chikara said:


> 2) How hard is it to locate and change this "internal switch."








If you drill a hole in the bottom of the charger you can change the switch from outside.


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## Rosoku Chikara

HKJ said:


> ...According to some other reviews I have seen it works...<snip>



Thanks for your very prompt reply. I am interested in a multi-chemistry charger, but I need LiFePO4.

This Opus BT-C3100 V2.1 may be the best solution available today. (Am I correct?)


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## HKJ

Rosoku Chikara said:


> Thanks for your very prompt reply. I am interested in a multi-chemistry charger, but I need LiFePO4.
> 
> This Opus BT-C3100 V2.1 may be the best solution available today. (Am I correct?)



I do not really like the internal switch, if it is supposed to be used it must be external.

There are some cheap chargers that can do NiMH + LiIon 3.6/4.2 volt. I am testing one now, but I have not looked at the result yet.
For handling LiIon with different voltage, Xtar has some very good chargers (VP2 & SP1).


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## Rosoku Chikara

Thanks again for your many excellent reviews, and continuing good advice.

I have already looked at your reviews of both the Xtar VP2 and SP1. But, as you say, they do not charge NiMH. 

Most of my devices use AAA or AA Ni-MH. I have recently purchased some 10440 and 14500 LiFePO4 which I am now using in certain applications that can safely accept and benefit from the higher voltage. So, I am interested in a good (acceptable) charger that can charge both NiMH and LiFePO4. 

I already have a Maha C9000 for NiMH, but I think it would be most convenient if any new charger I purchase could charge both chemistries. I also like the fact that this Opus C3100 V2 is an "analyzer" similar to the Maha C9000, not just a charger.

(While it would be nice to know that -if I ever needed to- I could charge other types of LiIon cells, at this point in time, I have no need and no particular interest in the other LiIon chemistries. So, in my particular case, I would probably switch the internal switch to 3.7V and just leave it there.)

Anyway, I am still "just looking." So, I will keep checking your reviews for something better than this Opus C3100 V2.


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## tatasal

This charger's price has just been reduced to $42. ( use coupon code OP3100). They have just sold the 100th unit, hence, the reduction.


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## N8N

Thanks for the review. As a user of NiMH, Li-Ion, and LiFePO4 I am intrigued by 'the switch' and am looking forward to more reviews/testing of this charger... would be nice to have a proper smart charger to complement my C9000, although I've had no problems with my i4 v2 or Surefire LiFePO4 charger.


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## UnknownVT

tatasal said:


> This charger's price has just been reduced to $42. ( use coupon code OP3100). They have just sold the 100th unit, hence, the reduction.



Thank you for that heads-up -
seems like a very good charger to try out at this coupon price.

The only thing that may prevent it from being an ideal charger is being only capable of 1 Amp charge for 4x NiMH.

I only really needed this since the advent of the Eneloop XX @ ~2450mAh 
and their re-badged clones - Duracell Ion Core AA (link to thread) -
where 0.5C would require 1200-1225mA charge current 
(I do realize the Opus 3100 is capable of up to 2Amp charge current but this is only for to 1-2 NiMH)

Does anyone know if the manual is available on-line please?
or be willing to scan and post it?

Thanks


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## Wiggle

Just got my Opus 2.1, liking it so far. I am thankful for the analyzing capability of this charger, it will let me sort and trim down my battery collection once I am able to quantify the performance/capacity of my cells a bit. My Nitecore I4 sadly croaked a few months back and this one is definitely a step up (though the I4 was simple and worked well before failing). I may still use my WF139 charger which has faithfully served me for years and always terminates correctly but this one will get some serious use too.


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## subwoofer

Fantastic review and very thorough testing. Many thanks HKJ

I'm assuming that the firmware is not upgradable by the user? (in which case it is important to buy the V2.1)


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## Wiggle

HKJ said:


> Same as above, but I am using an my own power supply, notice the green current scale. The charger is using considerable more than 3A from the power supply in spikes.
> 
> 
> 
> 
> 
> 
> Same curve as above, but I have removed the "DC input current" from the chart. It can be seen that the charger charges perfectly with 1A and there is not any significant difference between this curve and the one above made with the original power supply.



Am I correct in assuming that this means that even with a limited current of 1A on supply side the charger can still correctly charge at 4 x 1A? Just a little confused cause it seems like more energy is going into the batteries than is being pulled from the power supply (1000 mA x 12V is less than 1000 mA * 4 * 3.7V).


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## HKJ

Wiggle said:


> Am I correct in assuming that this means that even with a limited current of 1A on supply side the charger can still correctly charge at 4 x 1A? Just a little confused cause it seems like more energy is going into the batteries than is being pulled from the power supply (1000 mA x 12V is less than 1000 mA * 4 * 3.7V).



No.
The supplied power supply is 3A and doing an average of my measured current for the first 15 minutes gives 2.2A.
With NiMH the average is 1.3A


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## Wiggle

Ah gotcha, thanks for the clarification.


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## Wiggle

The analyzing features are nice, I have already been able to pick out one bad cell (just a cheap Trustfire so no big shock here) and confirmed that even after 20 months use in my EDC (with lots of 500 lumen burst mode use) my Zebralight 14500 cell still has about 760 mAh of capacity, not too far down off the rated 880 mAh for that much use.


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## UnknownVT

HKJ said:


> No.
> The supplied power supply is 3A and doing an average of my measured current for the first 15 minutes gives 2.2A.
> With NiMH the average is 1.3A



Thanks for the measurements - 
here's a more simple minded explanation - 
4x NiMH AA @ 1Amp charge current each is 4x 1.2V x 1A = 4.8watts 
(to perhaps 6watts max - these are worst possible cases where if it were theoretically possible for the cells to start at 0 Volts!!!)

The power supply is rated for 3Amps _BUT_ @ 12Volts = 3Ax12V = 36watts
so the power supply should be more than adequate to charge 4x NiMH AA batteries.

I would have thought it was adequate for 2Amps for 4x NiMH AA - 
but seems from HKJ's figures it probably would not for the first 15mins -
but it ought to be able to support a charge current of 1.2+Amps for 4x NiMH AA.


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## HKJ

UnknownVT said:


> Thanks for the measurements -
> here's a more simple minded explanation -
> 4x NiMH AA @ 1Amp charge current each is 4x 1.2V x 1A = 4.8watts
> (to perhaps 6watts max - these are worst possible cases where if it were theoretically possible for the cells to start at 0 Volts!!!)
> 
> The power supply is rated for 3Amps _BUT_ @ 12Volts = 3Ax12V = 36watts
> so the power supply should be more than adequate to charge 4x NiMH AA batteries.
> 
> I would have thought it was adequate for 2Amps for 4x NiMH AA -
> but seems from HKJ's figures it probably would not for the first 15mins -
> but it ought to be able to support a charge current of 1.2+Amps for 4x NiMH AA.



You did not read the 3. line in my reply, that contains the current reading for NiMH.

When charging NiMH the voltage is up to 1.5 volt, i.e. you are charging 6 watt to charge.into the batteries, not 4.8 watt.

Also note that my current calculation was for the first 15 minutes, but the highest current will be drawn just before the charger starts reducing the charge current, at least if the converter inside the charger has the same efficiency.

I could easily add a "Average DC current" trace, but I believe that there is already to many traces in the chart.


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## UnknownVT

HKJ said:


> You did not read the 3. line in my reply, that contains the current reading for NiMH.
> 
> When charging NiMH the voltage is up to 1.5 volt, i.e. you are charging 6 watt to charge.into the batteries, not 4.8 watt.
> 
> Also note that my current calculation was for the first 15 minutes, but the highest current will be drawn just before the charger starts reducing the charge current, at least if the converter inside the charger has the same efficiency.
> 
> I could easily add a "Average DC current" trace, but I believe that there is already to many traces in the chart.



HKJ,

Thanks for the response - 
yes, I did read your 3rd line in you very helpful reply, thanks -

perhaps you didn't see the last para of my post? 
stating where I "thought" the power supply should be able to support charging 4x NiMH AA @ 2A -



UnknownVT said:


> I would have thought it was adequate for 2Amps for 4x NiMH AA -
> but seems from HKJ's figures it probably would not for the first 15mins -
> but it ought to be able to support a charge current of 1.2+Amps for 4x NiMH AA.



re: 4.8watts vs 6watts


UnknownVT said:


> (to perhaps 6watts max -



The point was the power supply is rated 36watts 
and the max charge for 4x NiMH AA @ 1A is only 6watts.

I just checked my Maha/PowerEx C9000 power supply and it is only rated for 2A @ 12volts - and yet the C9000 can charge 4x NiMH @ 2A.

Thank you for your very helpful thorough reviews and posts.


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## HKJ

The maximum power draw from the supply is not when the batteries has 0 volt, but just before the charger stops or reduces current.
0 volt at X amperes only requires -> 0*X -> 0 watt.

The charger has more than enough power to charge at NiMH 2A. It is probably done the way it is to make NiMH and LiIon as equal as possible.


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## UnknownVT

HKJ said:


> The maximum power draw from the supply is not when the batteries has 0 volt, but just before the charger stops or reduces current.
> 0 volt at X amperes only requires -> 0*X -> 0 watt.
> 
> The charger has more than enough power to charge at NiMH 2A. It is probably done the way it is to make NiMH and LiIon as equal as possible.



Thanks for the explanation -
perhaps I ought to explain my 0volt comment -
I was thinking in terms of the difference between a "full" battery and one that was "empty" -
I used a theoretical empty battery as 0volts (which I know is not physically possible)

Would you please explain why the current draw on charger power supply is 2.2A for the first 15minutes ?

Thanks


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## HKJ

UnknownVT said:


> perhaps I ought to explain my 0volt comment -
> I was thinking in terms of the difference between a "full" battery and one that was "empty" -
> I used a theoretical empty battery as 0volts (which I know is not physically possible)



But as I written before: The maximum power draw is when the battery is nearly full.



UnknownVT said:


> Would you please explain why the current draw on charger power supply is 2.2A for the first 15minutes ?



I did an average of the first 1000 data point in my log file, that is the reason that the value is for the first 15 minutes (I log one record each 0.9 second). I could have done the average anywhere in the logfile, but the beginning is easy to find. The end is not usable, except if I want the idle current.

The charger is charging with 1A at about 3.5 volt (LiIon see charge curve in review), this means the charge power is 1A*3.5V*4 -> 14 watt, but it uses 2.2*12 -> 26.4 watt from the power supply


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## UnknownVT

HKJ said:


> But as I written before: The maximum power draw is when the battery is nearly full.



Thank you for that, I understand.



HKJ said:


> I did an average of the first 1000 data point in my log file, that is the reason that the value is for the first 15 minutes (I log one record each 0.9 second). I could have done the average anywhere in the logfile, but the beginning is easy to find. The end is not usable, except if I want the idle current.
> 
> The charger is charging with 1A at about 3.5 volt (LiIon see charge curve in review), this means the charge power is 1A*3.5V*4 -> 14 watt, but it uses 2.2*12 -> 26.4 watt from the power supply



I can see that, it is for LiIon?

For 4x NiMH AA is the initial current draw different, please?

Thanks


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## HKJ

UnknownVT said:


> For 4x NiMH AA is the initial current draw different, please?



That was the 3. line I was referring to before, the current draw is 1.3A.


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## UnknownVT

HKJ said:


> That was the 3. line I was referring to before, the current draw is 1.3A.



Thank you sorry to appear to be so dense or not reading/comprehending your posts.

So there is no peak current draw for the first 15mins from the power supply when charging 4x NiMH AA?

Therefore it is more than adequate to support even 2A charge current for 4x NiMH?


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## HKJ

UnknownVT said:


> So there is no peak current draw for the first 15mins from the power supply when charging 4x NiMH AA?



Nothing extraordinary, there is 3A peaks each cycle, but with LiIon it has 6A peaks.



UnknownVT said:


> Therefore it is more than adequate to support even 2A charge current for 4x NiMH?



Yes, it has power enough.
In the first version of the charger channel #1 & #4 had a different circuit, but in this version it looks like all channels are the same.
My guess is that it could be changed in software (if the charger has enough cooling).


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## UnknownVT

HKJ said:


> Nothing extraordinary, there is 3A peaks each cycle, but with LiIon it has 6A peaks.
> 
> Yes, it has power enough.
> In the first version of the charger channel #1 & #4 had a different circuit, but in this version it looks like all channels are the same.
> My guess is that it could be changed in software (if the charger has enough cooling).



Thank you HKJ for your patient replies. Much appreciated.


----------



## kaichu dento

Can anyone tell me whether the Opus or the Sysmax/Nitecore i4 Intellicharger would be the better one-solution charger?

I have batteries from 10280 > 18650 and a few other points in between.


----------



## tatasal

kaichu dento said:


> Can anyone tell me whether the Opus or the Sysmax/Nitecore i4 Intellicharger would be the better one-solution charger?
> 
> I have batteries from 10280 > 18650 and a few other points in between.



The i4 is pure charger only.

The BT-C3100, as seen in HKJ's review in this thread, is a charger/discharger/analyzer and much more. More like a 4-independent channel hobby charger with built-in cradles already.


On the other hand,
for lack of something to do over the weekend, I tested my Panasonic NCR18650B 3400mah cell's discharge capacity:
Charger used to charge cell to 4.2V at 1A rate: Xtar VP2 (both times)(resting voltage at testing: 4.17v)
Discharged via: iCharger 106B+ = 3234mah (at 1A discharge rate, programmed to terminate at 2.8v)
Discharged via: BT-C3100 v2.1 = 3226mah (at 1A discharge rate, terminated at 2.8v)
Difference: 8 mah!




!


!


!


----------



## Wiggle

kaichu dento said:


> Can anyone tell me whether the Opus or the Sysmax/Nitecore i4 Intellicharger would be the better one-solution charger?
> 
> I have batteries from 10280 > 18650 and a few other points in between.



I used to own an I4 (it failed on me though). But I can say after spending some time with the Opus that it is superior to the I4 in many ways. It has to be your call whether or not the additional cost is worth the improvement though.


----------



## realista

niiiiiiiiiiiiiiiice test TATASAL ! so the quality of testing of this charger is = to an hobby charger. very, but very good !!!!

*I RECEIVED THIS CHARGER!!!
*i am wondering 1 thing. could i use this charger to TEST the real mah of a smartphone battery?
i should connect + and - poles and do the test. BUT I DON'T KNOW if smarphone batteries do have 4,2 or 4,35 cut off voltage while charging.

_*something like this *_http://www.batterymart.com/images/products/alt/usc-002.jpg

and second problem, i should find an adjustable cradles for flat liion cell. i found some cradles chat charges ALL TYPE/BRAND of battery(with adjustable pins), should i consider to buy it opening it, and leave all electronic just to use the basic "cradle" funcion?


----------



## tatasal

realista said:


> niiiiiiiiiiiiiiiice test TATASAL ! so the quality of testing of this charger is = to an hobby charger. very, but very good !!!!
> 
> *I RECEIVED THIS CHARGER!!!
> *i am wondering 1 thing. could i use this charger to TEST the real mah of a smartphone battery?
> i should connect + and - poles and do the test. BUT I DON'T KNOW if smarphone batteries do have 4,2 or 4,35 cut off voltage while charging.
> 
> _*something like this *_http://www.batterymart.com/images/products/alt/usc-002.jpg
> 
> and second problem, i should find an adjustable cradles for flat liion cell. i found some cradles chat charges ALL TYPE/BRAND of battery(with adjustable pins), should i consider to buy it opening it, and leave all electronic just to use the basic "cradle" funcion?



Your link can be used as 'cradle-only' for a DIY mah testing, with the wires coming from it connected to the terminals of the 3100 (or a hobby charger.)

I have seen a discussion in BLF regarding newer Samsung smartphone models having 4.35v batteries. All of my old Nokia phones are still 4.2V though.


----------



## realista

i have some problems about the configuration of this charger. i don't understand when the work is finished....ecc.
and i think it hase some problems with protected batteries. When i insert a fully charged 18650 protected ( asucell 3000mah yellow) it displays "null".

maybe the protecion circuit disable the cell? i don't understand. i insert this battery, i select DISCHARGE mode, and to start the mode I JUST WAIT some seconds, right? but with this cell nothing appear. i only see "null".


----------



## HKJ

null means "no battery detected".


----------



## realista

and this is strange. seems to not detect the fully charged battery. could interfere the protection circuit installed in some batteries?

UPDATE. i noticed the charger do take a long time do display FULL battery. seems that at about 4,1v does take too much time to arrive to 4,15, 4,2........ i dont think it is normal. ok the final curve could be slower...but it is a lot slower. I should manually leave the battery also if do not show "full" but it is imho 99,5% full!


----------



## Julian Holtz

*When does fan start?*

Hello HKJ,

thanks a lot for your expertise here.
I have a question concerning the fan. When I charge 2 cells LiIon or NiMh in the standard setting with 0.5A, will this be enough for the fan to start, or will it stay off?

Thanks,

Julian


----------



## realista

*Re: When does fan start?*

i reply to ur quwstion. yes, the fan does start with 2 nimh charging at 500mah. it sounds strange........ but true. i am charging 2 eneloop xx 2500mah...and sometimes the fan do start. then stops, then restart.....


----------



## Julian Holtz

*Re: When does fan start?*

Thanks for your information! That's really a bummer - I like to keep my chargers at my nightstand. Oh well, the market is big enough.


----------



## tatasal

*Re: When does fan start?*

The fan is programmed to engage if internal temperature reaches 40 celsius.


----------



## Julian Holtz

*Re: When does fan start?*

Well, 40°C is not that much. I wonder what would happen if I were to install a switch for the fan, to manually disable it for charge currents <= 500mA.
There are other chargers without fans that have no problems with these currents. Even if the electronics heated up to 60°C, which I doubt, this would still not be a problem for today's semiconductors.


----------



## realista

*Re: When does fan start?*

in fact, my maha c900 think go over 40c but does not ave fan. i thought fan was for over 1000mah current. the opus output 2000mah on 1 and 4 slot. i never imagined fan do start at 500mah charge current.
THE FAN IS REALLY LITTLE. are there any replacement of this fan? it is precisely 2,4 cm x 2,4


----------



## Julian Holtz

*Re: When does fan start?*

I just ordered this one, it is supposed to be very silent:

http://www.ebay.de/itm/231085074387


----------



## oKtosiTe

*Re: When does fan start?*



Julian Holtz said:


> I just ordered this one, it is supposed to be very silent:
> 
> http://www.ebay.de/itm/231085074387


Sunon isn't exactly top-of-the-line, but you could do a *lot* worse with many no-name fans.
An option if temperature is less of an issue than fan noise is to add a resistor to run it at lower speed. This is what I did with an amplifier; it originally came with a no-name fan that died within months. It was one out of four amplifiers (80,120,240,500W at 8Ω) built with the exact same case. Because of its lower wattage and the high-end fan I replaced the old one with, a lower fan speed was perfectly fine. So now my living room is quiet once more.


----------



## Julian Holtz

*Re: When does fan start?*

I use Sunon fans in all of my iChargers, and they never failed me in many years. :thumbsup:

I will check how hot the charger gets if the fan is purposely disconnected at 0,5A charge current. As it switches of automatically at 60°C, I don't think I run the risk of a meltdown here. I'll also check the type of the SOP-8 transistors and see if I can add a heatsink to them.

So I will enable the fan only when I don't need total silence and when I'll charge at higher currents or discharge. My charger should arrive tomorrow, I'll see then.


----------



## UnknownVT

UnknownVT said:


> Thank you for that heads-up -
> seems like a very good charger to try out at this coupon price.
> 
> Does anyone know if the manual is available on-line please?
> or be willing to scan and post it?



I just received my v2.1 using the discount coupon code - thanks.

So I have scanned the brief (and not very clear) manual and put it into a pdf file -

Opus BT-CT3100v2.1 Manual - Download pdf (1.05MB)


----------



## realista

thank u good work.


----------



## tatasal

Henry Xu of Opus sent me two pre-production v2.1 chargers. As you can see in the first pic, it does not yet have the Opus logo printed in the upper right hand portion in the housing of the production model. (mine is the same non-logo model reviewed by HKJ in this thread)

The stock fan of the v2.1 is actually much quieter than the ones in the original versions. I also have the v2.0, btw.

I experimented with one of the charger's cooling by putting a 12VDC, .13A, brush-less fan salvaged from common ATX PC power supplies at the bottom of the charger. I cut the wires that powers the stock fan then connected it to the new fan at the bottom. The air sucked by the new fan passes from the top, through the charger's 4 cradle rails, cooling the cell/s and electronics below and finally exiting through the original horizontal cooling and round holes I made. My project will not win workmanship awards but nevertheless attained my goal of using a quieter fan. 

Since the fan pulls in more cooling air than the stock one, it is not only more quiet but it turns off automatically much earlier since it cools the charger much faster, triggering the sensors that control the fan to turn off the power to the fan much earlier.


----------



## Conte

I've noticed these chargers popping up in ebay now with different names on then. I wonder they are the same thing re labeled or crappier quality knockoffs.


----------



## UnknownVT

Just got mine (thanks to the discount code)




I was using it to test some lithium IMR batteries I recently acquired - AW and TrustFire
when I got this....




An AW IMR16340 tested capacity was 1028mAh!!!
Is this even possible?
the rating was 550mAh printed on the side of the battery
(FWIW - I was using 300mA current for all those IMR batteries)

I waited until the other IMR batteries were complete -



This shows the other 3 IMR batteries gave "sensible" measurements 
including another AW IMR16340 (=506mAh).

I had already used that slot to test an old unprotected 16340 and that was 543mAh -
so that slot seems "sensible"

This is why I am so taken aback by this test measurement.
(I don't think a capacity of 1028mAh for an IMR 16340 is even remotely possible)

Of course this could just be a glitch -
so I've put that AW IMR 16340 back in for another Test cycle in another slot - 
while I am testing a TrustFire IMR16340 in the slot that gave 1028mAh.

Will report when those are complete.

Observation of the Test cycle - the Opus BT-C3100v2.1 does not seem to give any "Rest" period 
between initially charging and the discharge
then between fully discharged and charging back up - whereas the 
Maha/PowerEX C9000



with the Maha/PowerEX C9000 the Charge and Discharge current rates are programmable -

BUT on the Opus BT-C31000v2.1 the discharge current is the same as the charge current.


----------



## HKJ

Try checking the battery in another slot and see if it gives the same result again.


----------



## kaichu dento

HKJ said:


> Try checking the battery in another slot and see if it gives the same result again.


Exactly what I was thinking - might be a problem with the particular slot as opposed to the battery, or the charger as a whole.


----------



## kreisl

UnknownVT said:


> Observation of the Test cycle - the Opus BT-C3100v2.1 does not seem to give any "Rest" period
> between initially charging and the discharge
> then between fully discharged and charging back up - whereas the
> Maha/PowerEX C3000



http://www.candlepowerforums.com/vb...ger-analyzer&p=4510981&viewfull=1#post4510981


----------



## UnknownVT

UnknownVT said:


> Of course this could just be a glitch -
> so I've put that AW IMR 16340 back in for another Test cycle in another slot -
> while I am testing a TrustFire IMR16340 in the slot that gave 1028mAh.
> 
> Will report when those are complete.





HKJ said:


> Try checking the battery in another slot and see if it gives the same result again.





kaichu dento said:


> Exactly what I was thinking - might be a problem with the particular slot as opposed to the battery, or the charger as a whole.



Thank you gentlemen for the advice - as you see we are thinking along the same lines.

These were the measurements that I got overnight:




That AW IMR16340, which got a reading of 1028mAh in Slot #1, is now in Slot #4 and its measurement is now 544mAh - 
which is a much more realistic reading.

BUT the TrustFire IMR16340 that I did a Test Mode in Slot #1 at the same time gives a measurement of 1099mAh!!!! simply not realistic or "sensible" -
I think this shows there is a problem with Slot #1 on my brand new only just received Opus BT-C3100v2.1.

So I guess with the bad behavior of Slot #1 on my brand new just received Opus BT-C3100v2.1 - 
I'll be contacting Gearbest.com to see about addressing the issue.


I had also said about Slot #1:


UnknownVT said:


> I had already used that slot to test an old unprotected 16340 and that was 543mAh -
> so that slot seems "sensible"



That old unprotected LIR 123A/16340 is now in Slot #3 -
and its reading in that slot is now 156mAh!
So the so-called "sensible" reading of 543mAh that I got in Slot #1 was also wrong, and WAY over capacity -
it seems that that old LIR 123A/16340 is at the end of its life-cycle.

Just out of interest Slot #2 showing the -- -- mAh - actually had a reading (I can't remember exactly but it was in the region of 2-3XXmAh) 
as I was just about to take the photo - setting the lights and and my camera - 
the reading changed to -- --mAh and indicating it was charging.

My uneducated take is that the voltage had dropped below 4.0V and the charger decided to charge it back up to 4.2V
as per manual:



then went back into the Test Mode and was discharging the battery (as I took the pic - that's why it says Discharge in Slot #2)

Literally right after I removed the other 3 batteries - that slot gave a reading - so it was only a matter of minutes definitely <20mins



cough! - I think that battery is on its last legs......

Thanks for the help and suggestions so far.


----------



## UnknownVT

kreisl said:


> http://www.candlepowerforums.com/vb...ger-analyzer&p=4510981&viewfull=1#post4510981



Thank you very much for the useful link.

My observation for the Test Mode of the Opus BT-C3100v2.1 is 
it does a final full charge of the battery 
so to use your nomenclature -

short: *C *> nR > *D* > nR > *C *
(addition highlighted in Red)

At the end of the cycle the display (using the Display button)
flashes between Full and the capacity in mAh.

Thanks


----------



## HKJ

UnknownVT said:


> Thank you very much for the useful link.
> 
> My observation for the Test Mode of the Opus BT-C3100v2.1 is
> it does a final full charge of the battery
> so to use your nomenclature -
> 
> short: *C *> nR > *D* > nR > *C *
> (addition highlighted in Red)



You can always check my reviews for the behaviour.
A LiIon charge test looks this way (charge discharge charge there is no rest period):


----------



## kreisl

UnknownVT said:


> short: *C *> nR > *D* > nR > *C *
> (addition highlighted in Red)



Thanks for the info. I've corrected the post!


----------



## UnknownVT

kreisl said:


> Thanks for the info. I've corrected the post!



Sure, and thanks to HKJ for the graphic showing the Test Mode cycle from his review.

But you might want to update your long description
which is currently still:


kreisl said:


> BT-C3100 so-called "TEST MODE":
> charge - no rest - full discharge,



you'll need to add the 
- no rest - final full charge.

and from my observation of Test of that old LIR 123A/16340 ("3" - on its last legs) 
it seems at the end of the Test Mode Cycle -
if the battery drops below 4.0V the charge will do its maintenance charge back up to 4.2V
then do the discharge to obtain the "new" capacity 
and another "final" full charge.

My guess is it probably will repeat this ad-infinitum if the battery is left in the charger on the Test Mode.


----------



## kreisl

yoh. done.

thanks again! 

i've been test cycling ncr-a in the skyrc. the timer cut-off refers to the single program routines instead of the total time. this is wrong imho..


----------



## realista

UnknownVT said:


> Thank you very much for the useful link.
> At the end of the cycle the display (using the Display button)
> flashes between Full and the capacity in mAh.
> 
> Thanks


just little question, capacity is read during DISCHARGING moment or charging moment? if when discharging.....i think pressing "display" should show capacity eve if the final charge is not completed. is it right?

@unknown you said *the discharge current is the same as the charge current. *so in the test mode......when u charge a battery at 200mah is discharged at 200.... but if you charge at 2000 will be discharged at 2000.
I don't like that i cannot choose the discharge rate. one person could prefer to charge FAST a battery but to discharge at only 200/300mah . 
ABOUT THIS............. what is the "best" dircharge current to get "quite real" capacity? how do factory rate batteries? if i am not wrong..... i remember 500mah. but i could remember wrong. the true thing id that if you discharge a battery at 1000/1500/2000mah the final capacity readings are lower.......


----------



## UnknownVT

realista said:


> just little question, capacity is read during DISCHARGING moment or charging moment? if when discharging.....i think pressing "display" should show capacity eve if the final charge is not completed. is it right?



I can only speak for the Test Mode -

While discharging there is no display of mAh.

Once discharge is finished - the mAh is displayed - an continues to be available during final full charge.

When charge is completed - Full is displayed alternating with the mAh.




realista said:


> @unknown you said *the discharge current is the same as the charge current.* so in the test mode......when u charge a battery at 200mah is discharged at 200.... but if you charge at 2000 will be discharged at 2000.





realista said:


> I don't like that i cannot choose the discharge rate. one person could prefer to charge FAST a battery but to discharge at only 200/300mah .
> ABOUT THIS............. what is the "best" dircharge current to get "quite real" capacity? how do factory rate batteries? if i am not wrong..... i remember 500mah. but i could remember wrong. the true thing id that if you discharge a battery at 1000/1500/2000mah the final capacity readings are lower.......



I was going by the manual - which I have commented is not very clear.

Bear in mind I have a sample of the Opus BT-C3100 v2.1 that is faulty in Slot #1 which gives obviously erroneous readings, so I cannot trust it and no longer using it at all - 
I don't know if this affects the rest of the charger.

However my observation - again in Test Mode -
If a charge current of 1Amp or 1.5Amp (I have not tried 2Amps) is set, then it appears for *NiMH batteries*, if the discharge current is 700mA.

You can see that in HKJ's review/opening post in the graph under: CHARGE TEST NiMH batteries, used to measure capacity - 
his charge current was 1Amp and discharge on the graph is about 700mA.

BUT for his graph of CHARGE TEST LiIon batteries, measure capacity - charge and discharge currents both look to be about 1Amp.

I try to use as close to 0.5C for the charge current and accept whatever the discharge current is set by the Opus.

On the Maha/PowerEX C9000 where the charge and discharge currents can be set individually - I use 0.5C for the charge and 0.2C for the discharge.


----------



## tatasal

In my Opus, I use the discharge mode to get the discharge capacity at the rate I like. Same with charging, I use the charge mode.

I don't use the its 'test mode' in li-lon since it's not useful and recommended anyway. 

Test mode is best used to condition tired niMh cells.


----------



## realista

why you say "not recommended" ? it is useful to have an all in 1 program that let you veridy the capacity if the battery. The only downside is that in this charger we can't set the current discharge rate. ( i don't understand if it is fixed 700mah nimh and 1000 liion).

ASSUMING THAT ( is it true or not??) is better to verify the mah fiilled into the battery in the DISCHARGE MOMENT........ one person should manually set:
1)charge 
2)_DIScharge at rate you want and verify the mah to see battery capacity_
3)charge

or....if could be the right way usethe CHARGING MOMENT to verify battery capacity :
1)discarge
2) _Charge at rate you want and verify the mah to see battery capacity

_*second option is convenient for time....... but i wait for the veterans to say us that is the correct moment to verify capacity.*


----------



## Wiggle

I've wondered this as well. It would be interesting to do a batch of cells and comparing the mean charge vs discharge mAh found. The way I've been testing my cells is
1) Charge up at any reasonable current
2) Discharge fully at a reasonable current based on the cell to measure the mAh
3) Charge up to 40% for cells that will be stored, charge to 90-100% for user or immediate standby cells.


----------



## wolfmanus

Hi All!

-I bought this 1 week ago. After a few days the fan is broken (the plain bearing is stringent). The fan almost always working at full speed (very loud and annoying).
-The voltage measurement is sometimes very inaccurate, reads low by 1-2 tenths of volts. (i have an AGILENT U1253B)


----------



## realista

i have the same problem of wolfman, the fan is starting do do NOISE, sometimes is difficult to start. When i plud first second the cd converter sometimes i hear noises from the fan.

i think some fan of the batch do have problems....and yes, it always start af 100% speed, no step down at 50 or 20%. i think the fan speed is too fast and over hours all fan will start to have problems.
EDIT: i noticed that 8 times on 10 every time the fan start, do make noise. but after 5 seconds noise disappear...... mmmmhh


----------



## UnknownVT

wolfmanus said:


> -I bought this 1 week ago. After a few days the fan is broken (the plain bearing is stringent). The fan almost always working at full speed (very loud and annoying).
> -The voltage measurement is sometimes very inaccurate, reads low by 1-2 tenths of volts. (i have an AGILENT U1253B)





realista said:


> i have the same problem of wolfman, the fan is starting do do NOISE, sometimes is difficult to start. When i plud first second the cd converter sometimes i hear noises from the fan.
> i think some fan of the batch do have problems....and yes, it always start af 100% speed, no step down at 50 or 20%. i think the fan speed is too fast and over hours all fan will start to have problems.



It would seem that there may be quality issues with the Opus BT-C3100 (v2.1).

My sample's issue was much more severe - 
Slot #1 (leftmost) gave unrealistic/erroneous readings - 
enough that I cannot trust it will not over-charge or over-discharge my batteries - so I would not use it at all - 
with one of the important slots that can charge above 1Amp unusable -
if using slot #4 (rightmost) to charge at above 1A - the use of any of the other two slots (#2 or #3) reduces the charge in #4 down to 1A -
so effectively a 3-slot 1A charger (or 1-slot charger above 1A).

I opened a ticket with GearBest.com almost immediately with full description and photo evidence of the defect
(as described in posts #55 and #59 of this thread)

GearBest basically gave me the (polite and amicable) runaround - 

Even after finally managing to come to an agreeable arrangement of a partial refund 
without me having to return the defective unit (very expensive with tracking to China, and they will not pay for return shipping),
they did not actually make the agreed and promised partial refund, 
and even asked inexplicably for evidence of the defect two more times.

It was not until today - after I opened a dispute at PayPal (where PayPal holds their funds) -
that the "offer" of the partial refund was made on PayPal.

I hope defective product is not the norm -
although I think the customer service is.


----------



## lardyl

UnknownVT said:


> It would seem that there may be quality issues with the Opus BT-C3100 (v2.1).
> 
> My sample's issue was much more severe -
> Slot #1 (leftmost) gave unrealistic/erroneous readings -
> enough that I cannot trust it will not over-charge or over-discharge my batteries - so I would not use it at all -
> with one of the important slots that can charge above 1Amp unusable -
> if using slot #4 (rightmost) to charge at above 1A - the use of any of the other two slots (#2 or #3) reduces the charge in #4 down to 1A -
> so effectively a 3-slot 1A charger (or 1-slot charger above 1A).
> 
> I opened a ticket with GearBest.com almost immediately with full description and photo evidence of the defect
> (as described in posts #55 and #59 of this thread)
> 
> GearBest basically gave me the (polite and amicable) runaround -
> 
> Even after finally managing to come to an agreeable arrangement of a partial refund
> without me having to return the defective unit (very expensive with tracking to China, and they will not pay for return shipping),
> they did not actually make the agreed and promised partial refund,
> and even asked inexplicably for evidence of the defect two more times.
> 
> It was not until today - after I opened a dispute at PayPal (where PayPal holds their funds) -
> that the "offer" of the partial refund was made on PayPal.
> 
> I hope defective product is not the norm -
> although I think the customer service is.



In a very similar position with fan starting off ok (for a week) but now unable to spin up unless I stand the unit up on the bottom edge or twist the case a little. It is also very nosy, clearly the impeller is fouling and it sounds like a three year old cheap pc case fan.
Also noticed the "odd" capacity reading from the left hand display when doing a charge/refresh cycle.
I am in negotiation with supplier over return/repair costs at present. Do you mind me asking what they agreed to in the form of a partial refund? I'm thinking about modding the unit with another case fan that can start at full speed more reliably and a contribution from GearBest would help me to decide to keep it. I can't find anyone obvious to repair it and the way the fan is retained is not particularly conducive for a direct replacement (for my limited skills at least).
Thanks


----------



## UnknownVT

lardyl said:


> In a very similar position with fan starting off ok (for a week) but now unable to spin up unless I stand the unit up on the bottom edge or twist the case a little. It is also very nosy, clearly the impeller is fouling and it sounds like a three year old cheap pc case fan.
> Also noticed the "odd" capacity reading from the left hand display when doing a charge/refresh cycle.
> I am in negotiation with supplier over return/repair costs at present. Do you mind me asking what they agreed to in the form of a partial refund? I'm thinking about modding the unit with another case fan that can start at full speed more reliably and a contribution from GearBest would help me to decide to keep it. I can't find anyone obvious to repair it and the way the fan is retained is not particularly conducive for a direct replacement (for my limited skills at least).
> Thanks



Sent you PM with details.

My sample was not just giving wrong/erroneous/impossible readings in slot #1 (leftmost)
but charge/discharge times were noticeably longer (almost double) for the currents chosen -
I cannot figure out what was wrong with Slot #1 -
hence my deep distrust of that slot - and I will not use it at all.

So in effect I have a 3-slot charger with one of the more important slots that can charge above 1Amp untrustworthy.

Good luck,


----------



## lardyl

UnknownVT said:


> Sent you PM with details.
> 
> My sample was not just giving wrong/erroneous/impossible readings in slot #1 (leftmost)
> but charge/discharge times were noticeably longer (almost double) for the currents chosen -
> I cannot figure out what was wrong with Slot #1 -
> hence my deep distrust of that slot - and I will not use it at all.
> 
> So in effect I have a 3-slot charger with one of the more important slots that can charge above 1Amp untrustworthy.
> 
> Good luck,



thanks very much I will bear that in mind


----------



## kreisl

Afaik the BT-C3100 v1.0 applied trickle charging *after* the DISCHARGE routine. Why? In order to prevent overdischarging through self-discharge (poor health battery) or auto-discharge (standby current draw of the machine). It was afaik the only charger-analyzer which did TRICKLE charging after DISCHARGING.

So the BT-C3100 v2.1 does not do this anymore?

Well, if there is no charger in the world which does/offers "TRICKLE-after-DISCHARGE" because it is a silly or unneeded thing, then I am arguing that the MC3000 should not offer it either.


----------



## HKJ

kreisl said:


> Afaik the BT-C3100 v1.0 applied trickle charging *after* the DISCHARGE routine. Why? In order to prevent overdischarging through self-discharge (poor health battery) or auto-discharge (standby current draw of the machine). It was afaik the only charger-analyzer which did TRICKLE charging after DISCHARGING.
> 
> So the BT-C3100 v2.1 does not do this anymore?
> 
> Well, if there is no charger in the world which does/offers "TRICKLE-after-DISCHARGE" because it is a silly or unneeded thing, then I am arguing that the MC3000 should not offer it either.




This kind of questions is easy enough to answer, just look at the curves in my review. None of them show any current after discharge.


----------



## kreisl

i looked at the 1.0 curves and 2.1 curves. The 2.1 curves don't show any current after discharge. The 1.0 curves show something. But the image resolution is too small.


----------



## StandardBattery

I think on a professional level charger one would not want to trickle after discharge simply because the user may want to measure the voltage of the cell after discharge, and would likely want to choose the charge rate if they wanted to bring the cell back up. It seems user Programs can be used to do this if desired, but it should not be automatic.


----------



## UnknownVT

kreisl said:


> Afaik the BT-C3100 v1.0 applied trickle charging *after* the DISCHARGE routine. Why? In order to prevent overdischarging through self-discharge (poor health battery) or auto-discharge (standby current draw of the machine). It was afaik the only charger-analyzer which did TRICKLE charging after DISCHARGING.
> 
> So the BT-C3100 v2.1 does not do this anymore?
> 
> Well, if there is no charger in the world which does/offers "TRICKLE-after-DISCHARGE" because it is a silly or unneeded thing, then I am arguing that the MC3000 should not offer it either.





kreisl said:


> i looked at the 1.0 curves and 2.1 curves. The 2.1 curves don't show any current after discharge. The 1.0 curves show something. But the image resolution is too small.





StandardBattery said:


> I think on a professional level charger one would not want to trickle after discharge simply because the user may want to measure the voltage of the cell after discharge, and would likely want to choose the charge rate if they wanted to bring the cell back up. It seems user Programs can be used to do this if desired, but it should not be automatic.



v1.0 may or may not do any trickle charging - HKJ's graph seems to show close enough to zero charge current (darker green line) even on lower res.

But I can confirm v2.1 does not apply any trickle charge after discharge - as I just discharged a couple of Duracell Ion-Core AA, and although the Opus BT-C3100 v2.1 did not indicate it had finished discharging -
the readings all showed unchanging steady state - as I was not sure if the discharge had finished, I left the batteries in the charger for several minutes longer to be sure that the readings were at unchanging steady state - 
and they remained so - so after approx 1/2 hour after I had found the steady state, I was confident enough of the finish of the discharge cycle, to remove the batteries.

_*NOTE: this is WRONG*_ - according to the manual v2.1 does apply a trickle charge after discharge completion (see post #82) - 
My apologies for this misleading post.


----------



## kreisl

UnknownVT said:


> v1.0 may or may not do any trickle charging



i am herewith confirming that v1.0 does trickle charging after discharge; i've measured it with NiMH battery, the trickle current is 2-4mA, average ~3mA:



and it also says so in the printed v1.0 instructions manual:






that's interesting. 
and it is also interesting that the v2.1 doesn't do it anymore.

the question is: does it make sense to have/offer such a thing?

To me, it doesn't make real sense. And it is in fact contradictory to real discharge functions such as DISCHARGE REDUCE (see iCharger, MC3000).


----------



## UnknownVT

kreisl said:


> i am herewith confirming that v1.0 does trickle charging after discharge; i've measured it with NiMH battery, the trickle current is 2-4mA, average ~3mA
> ...
> and it also says so in the printed v1.0 instructions manual



Ah! good catch (and confirmation).

My apologies, it seems v2.1 does trickle charge too - 
v2.1 manual:




My observation was flawed - probably because the period was too short - 
and/or the trickle charge current low enough that it made no difference to the readings.

Sorry for my misleading post.


----------



## kreisl

Thanks for the share Vincent, appreciated!
The LCD on my Opus says "0mA" too. But it is possible to measure the actual current, the trickling, with a multimeter, did you try it back then? Never mind.

Hobby chargers have a trickle charge parameter, for example iCharger offers {OFF|10|20|…|490|500}mA, and it is applicable to their CHARGE routines only. That makes sense. 30mA is a nice trickle charge rate to keep a normal battery at fully charged state. The Opus 3mA would be of little effect after a CHARGE routine; in turn this means that the "{OFF|10|20|…|490|500}mA" are absolutely not suitable for application after a DISCHARGE routine on a hobby charger, the rates are simply too high to keep a depleted battery at steady-state. With 10mA you could get a depleted AAA battery back to fully charged state after few days!

All that is helpful info. From that we are learning that "{OFF|10|20|…|490|500}mA" should only be applied to completed CHARGE routines, not DISCHARGE routines. 

And to keep things simple and stupid, a TRICKLE CHARGE -neither 30mA nor 3mA- should imo not be applied to any completed DISCHARGE routine because it is really unnecessary. "preventing the batteries from discharging any further for NiMh and NiCd battery" — i don't believe that's an urgent argument.


----------



## kosPap

this is a very detailed video review of the charger (the 2nd part has it dissasembled)

https://www.youtube.com/watch?v=IA-MZZD7HEQ
https://www.youtube.com/watch?v=JJxrDgEFxMU


----------



## realista

if i open it and change the selector to 3,6v is it ok to charge 4x lifepo4 batteries ?


----------



## StandardBattery

realista said:


> if i open it and change the selector to 3,6v is it ok to charge 4x lifepo4 batteries ?


In theory, other people have done it with various versions of the charger, but I don't know that there has been an analysis of the charge cycle. I'd do one and check the termination voltage and then you could check the capacity.


----------



## matt2

I purchased this because I had a bunch of older AA's around and my cheapy charger doesn't test them. I put the charger on "quick test" but it doesn't seem that consistent. Is there something I need to be doing to make it more consistent or did I just receive a malfunctioning charger? One time it said 5000 or so, then 72, then 121. Can I trust it enough to throw out some of these older but costly batteries? It was basically bought to recondition them if possible and if not, give me a reliable way to tell me when and what to throw away.


----------



## RI Chevy

Welcome to the Forum! :welcome:


----------



## StandardBattery

matt2 said:


> I purchased this because I had a bunch of older AA's around and my cheapy charger doesn't test them. I put the charger on "quick test" but it doesn't seem that consistent. Is there something I need to be doing to make it more consistent or did I just receive a malfunctioning charger? One time it said 5000 or so, then 72, then 121. Can I trust it enough to throw out some of these older but costly batteries? It was basically bought to recondition them if possible and if not, give me a reliable way to tell me when and what to throw away.


Quick Test attempts to determine the internal resistance of the battery, it is very sensitive to battery contact resistance. Check HKJ's review on this changer for how this feature tested. It is likely sensitive to temperature and maybe current charge state. It should in general give some indication, but maybe just analyzing the discharge capacity is a better idea to get the current capacity of the cell, even if it can no longer be used for higher current applications.


----------



## matt2

StandardBattery said:


> Quick Test attempts to determine the internal resistance of the battery, it is very sensitive to battery contact resistance. Check HKJ's review on this changer for how this feature tested. It is likely sensitive to temperature and maybe current charge state. It should in general give some indication, but maybe just analyzing the discharge capacity is a better idea to get the current capacity of the cell, even if it can no longer be used for higher current applications.



Thanks. Is there a certain % of what mah is good for its rating? I have one showing 300mah after "discharge/test" but rated at 2400mah and quick test shows 1200. So I assume it's probably not even good for a clock, is it? I just have so many old ones and I'm trying to sort them out. I made a battery box, a small cardboard box with holes drilled in it so I can keep my AA's arranged and hopefully sort by health if I can figure out a good system. Do most people recycle? I hate to throw them away but it's a small town, I don't have a clue where to take them.


----------



## StandardBattery

matt2 said:


> Thanks. Is there a certain % of what mah is good for its rating? I have one showing 300mah after "discharge/test" but rated at 2400mah and quick test shows 1200. So I assume it's probably not even good for a clock, is it? I just have so many old ones and I'm trying to sort them out. I made a battery box, a small cardboard box with holes drilled in it so I can keep my AA's arranged and hopefully sort by health if I can figure out a good system. Do most people recycle? I hate to throw them away but it's a small town, I don't have a clue where to take them.


That one seems well done . Maybe others can give more guidelines but if mine are at 50% I consider them ready for recycling as it's not worth the cost or time to maintain them as they may miss termination during charging. I use devices to determine capacity maybe more than chargers. If they don't power the device for the time I need I'll try to revive them once and still probably move them to a lower power device. Then they go for recycle next time. I only consider LSD for low drain devices otherwise they need charging too often. 

I hope most people recycle. Radio shack may still have recycle program, local fire stations often do. Ask around as many charities do it also.


----------



## Tm98

Most Home Depots or lowes has a recycling area for batteries.


----------



## Tacoboy

My BT-C3400 arrived a few days ago, so far I'm liking it.
But it's my first charger that I paid more then $10 for, so technically I have nothing to compare it to.


----------



## InHisName

I, too, charge / test all my old junk cells on it. I noticed that there seems to be an inconsistancy in what it does between successive charge / discharge cycles. One time I might discharge 1700 mAH, the next time the same cell discharges 27,567 mAH !! Obviously something has gone wrong with the 3100's methodolgy of calculations. HKJ, can you offer any explanations ? These odd discharge numbers have only occurred with the junkiest cells that I am attempting to categorize. BTW that cell above when in a low lumen flashlight, ran down in about the 90% of the hours I get from new Duraloops. So, that cell can put out up to 1700 mAH in low current demand devices. It's original mAH when I had it new & my C9000 was new, was 1977 mAH. It is a Duraloop that cycled weekly for 2 years, Then maybe 15-20 more in next 3 years. I'm guessing its at about 120 cycles of use, so far.


----------



## HKJ

InHisName said:


> HKJ, can you offer any explanations ?



I have a guess: The BT-C3100 works with pulses both during charge and discharge, these pulses are in the 2 to 3A range. If the battery is old it might have problems sustaining them and the charge may terminate a charge/discharge to early.


----------



## ShineOnYouCrazyDiamond

Hey - HKJ. There was a question in another charger recommendation thread about the 3100 vs the 3400. I had read in a review on Amazon someone saying that the 3400 was just the 3100 with the v2.1 rebranded as another model number for a particular manufacturer. Do you know anything about that?


----------



## HKJ

ShineOnYouCrazyDiamond said:


> Hey - HKJ. There was a question in another charger recommendation thread about the 3100 vs the 3400. I had read in a review on Amazon someone saying that the 3400 was just the 3100 with the v2.1 rebranded as another model number for a particular manufacturer. Do you know anything about that?



I have also heard that the 3400 is just a rebrand of the 3100 V2.1 for a specific dealer.


----------



## kreisl

The BT-C3400 is a _minimally _improved version of the BT-C3100v2.1 and for exclusive sale by the US seller who is an electronics expert and charger maker himself . One can always drop him an email and ask about these minimal differences, yet i for my part finally did lo inconcebible for xmas and gave away my very last Opus unit (it was v1.0) to a dear friend :wave:. I had't been using the Opus much for months, glad now to have cleared space in my drawer. I liked it, DC1, but it has been factually replaced by my prototype units of DC2.

It was clever enough to release the early iterations v1.0 and v2.0 to market already and gather WWW feedback for further product refinement. The v2.1 seems mature and satisfactory enough for its price point (~35$ GB promotion) and hopefully Opus continues with the BT-C3xxx development as planned. The next notable iteration of the Opus charger model will have an external voltage switch and support 3.6V/4.35V chemistries officially so i will be looking into picking up one the 2015 model.

Fact is, it easily takes 2+ yrs to develop an advanced battery charger to full maturity status. Fans of DC1, DC2 and USC really need some patience including myself


----------



## realista

ehehee, they will sell the same charger but with "official" capability to charge 3,6 and 4,35v batteries....... imho just marketing.


----------



## Tacoboy

I've been using my new BT-C3400 almost non-stop for the pass week, been working fine.


----------



## hammerjoe

We are now in 2015  and I was wondering if this is still the charger to get in the 30-40 dollar range?


----------



## hammerjoe

Am I reading correctly that this charger doesn't have a DISCHARGE/CHARGE (one time) function? It requires two steps, first put the batteries to discharge then put them to charge?

It seems that the Charge/test is the closest but it charges the unit first wasting a cycle.

I dont know alot about charger but isnt this kind of an important feature of any smart charger to have?


----------



## ChrisGarrett

hammerjoe said:


> Am I reading correctly that this charger doesn't have a DISCHARGE/CHARGE (one time) function? It requires two steps, first put the batteries to discharge then put them to charge?
> 
> It seems that the Charge/test is the closest but it charges the unit first wasting a cycle.
> 
> I dont know alot about charger but isnt this kind of an important feature of any smart charger to have?



Much like the LaCrosse chargers that discharge and then charge up in one step, we generally don't like that feature because unless we're standing right over the charger and have the ability to memorize 16 digits in sequence, we miss that number.

We want to be able to know the capacity of a given battery upon discharge.

Having a single step allows us to 'know' those numbers, regardless of whether we're off doing other things.

Chris


----------



## hammerjoe

ChrisGarrett said:


> Much like the LaCrosse chargers that discharge and then charge up in one step, we generally don't like that feature because unless we're standing right over the charger and have the ability to memorize 16 digits in sequence, we miss that number.
> 
> We want to be able to know the capacity of a given battery upon discharge.
> 
> Having a single step allows us to 'know' those numbers, regardless of whether we're off doing other things.
> 
> Chris


I apologise but you confused me with your post.
Doesnt the capacity show after the battery is charged and not after discharging?
I usually put the batteries after using them in my lacrosse and use the discharge feature which discharges the rest of the battery and charges it right after.

Is this wrong/not necessary?


----------



## ChrisGarrett

hammerjoe said:


> I apologise but you confused me with your post.
> Doesnt the capacity show after the battery is charged and not after discharging?
> I usually put the batteries after using them in my lacrosse and use the discharge feature which discharges the rest of the battery and charges it right after.
> 
> Is this wrong/not necessary?



The way you test capacity on any given battery/cell, is to charge it up fully and then discharge it at X, Y or Z current. Generally, the higher the discharge current, the lower the capacity will be for equal batteries/cells, both charged up to full.

The fact that a charger immediately goes into 'charge' mode after 'discharge,' makes it problematic to know what exactly was there in the tank, unless you get lucky.

Chris


----------



## hammerjoe

I understand what you are saying now.
The Bc9009 doesnt have that function to charge a battery and they discharge it afterwards afaik.

It has a discharge and then charge feature which I use alot and that is missing with the Opus unless I want it to do it three times with the discharge refresh function.


----------



## danielrhall

hammerjoe said:


> It has a discharge and then charge feature which I use alot and that is missing with the Opus unless I want it to do it three times with the discharge refresh function.


To determine the capacity of a cell, it has to be discharged completely from a full charge. That's what the Test function on the Opus BT-C3100 does; charge fully first, discharge fully, and then charge fully again. The capacity that is then read out is the discharge capacity. The final charge cycle isn't actually needed to determine the discharge capacity but the initial one is. The Maha MH-C9000 calls this function Refresh and Analyze Mode.


----------



## hammerjoe

How do we recondition a cell with this charger?
Why limit the cycle of the Discharge/Charge to only three? Does that guarantee the maximum recondition of a cell with no more need for extra cycles?


----------



## curlysir

Received the BT-C3400 today and initial impressions are favorable. It has 2.1 firmware. I was able to charge 4 18650 at 1000mA, (primary reason for the purchase). The fan does make some noise when it runs but where I use the charger the noise should not be a problem, It is in the same room as my computer and I generally have a TV on so I really didn't notice it, unless I was actually trying to hear the fan. I don't think this is a charger for a bedroom as the noise would be noticeable in a very quiet room.

This replaces a Nitecore D4 which is not a bad charger if you don't mind slow charging, It will only charge 4 18650 at 375mA or 2 at 750mA. I also considered buying a XTAR VP4, but it will only charge 2 18650 at 1000mA or 4 at 500mA , Do not understand why XTAR does not make a real 4 cell version of the VP2.

The BT-C3100 2.1 and the BT-C3400 appear to be the same charger. And from what I could find are just about the only 2 currently available for less then $50 that will charge 4 18650 (or others) at 1000mA.

The only minor annoyance I have (personal preference) and it applies to all Opus chargers is the backlight, I would prefer an option to turn the backlight on and off and not have it go off after so many seconds as it does now.


----------



## Tachead

curlysir said:


> Received the BT-C3400 today and initial impressions are favorable. It has 2.1 firmware. I was able to charge 4 18650 at 1000mA, (primary reason for the purchase). The fan does make some noise when it runs but where I use the charger the noise should not be a problem, It is in the same room as my computer and I generally have a TV on so I really didn't notice it, unless I was actually trying to hear the fan. I don't think this is a charger for a bedroom as the noise would be noticeable in a very quiet room.
> 
> This replaces a Nitecore D4 which is not a bad charger if you don't mind slow charging, It will only charge 4 18650 at 375mA or 2 at 750mA.* I also considered buying a XTAR VP4, but it will only charge 2 18650 at 1000mA or 4 at 500mA , Do not understand why XTAR does not make a real 4 cell version of the VP2.*
> 
> The BT-C3100 2.1 and the BT-C3400 appear to be the same charger. And from what I could find are just about the only 2 currently available for less then $50 that will charge 4 18650 (or others) at 1000mA.
> 
> The only minor annoyance I have (personal preference) and it applies to all Opus chargers is the backlight, I would prefer an option to turn the backlight on and off and not have it go off after so many seconds as it does now.



Why not just get two VP-2's? That's my plan when I get a light that uses 3-4 x 18650. I just grabbed one to start with to try it but, will order another when needed(I really like it so far). Having 2 separate chargers gives redundancy too. That way if one fails you still have the other to keep you going while you wait for repair/replacement.


----------



## curlysir

Tachead said:


> Why not just get two VP-2's? That's my plan when I get a light that uses 3-4 x 18650. I just grabbed one to start with to try it but, will order another when needed(I really like it so far). Having 2 separate chargers gives redundancy too. That way if one fails you still have the other to keep you going while you wait for repair/replacement.



Already have two VP-2's. But thanks  to this site I sometimes have the need to charge more then 4 batteries at a time. I bought the Nitecore D4 first and then purchased the VP-2's during the sales. After buying several 18650 powered flashlights, some using 4 batteries, I noticed the D4 was taking longer to charge then the VP-2 and realized the limitation of the D4. Started looking for a replacement for the D4 that would also charge NiMH and this lead to the C3100 and C3400. If XTAR every comes out with a true 4 cell version of the VP-2 I will probably get it too.


----------



## tobrien

has anyone heard about a v3.0 or something yet? I saw there's the "3400" but that's not anything really different it seems


----------



## GreatBizarro

Thanks for a thoroughly in depth review. Got one on order based on your information. The test ability alone is a great help as I am putting together some 18650 packs and can match cells.


----------



## realista

i shoot a picture of the internal switch. now it's easier to me to change it....


----------



## tobrien

realista said:


> i shoot a picture of the internal switch. now it's easier to me to change it....



nice work!!


----------



## hammerjoe

How accurate are the discharge and charge capacities displayed by the charger?

I am wondering how people are determining the real capacity of their cells. 
Do a full discharge and then charge and look at the capacity displayed by the display?
Do a full charge and then discharge and look at the discharge capacity on the display?

Or do the one of the above but calculate how long it took and multiply the time by the charge/discharge current?


----------



## tatasal

hammerjoe said:


> How accurate are the discharge and charge capacities displayed by the charger?
> 
> I am wondering how people are determining the real capacity of their cells.
> Do a full discharge and then charge and look at the capacity displayed by the display?
> Do a full charge and then discharge and look at the discharge capacity on the display?
> 
> Or do the one of the above but calculate how long it took and multiply the time by the charge/discharge current?



I have this charger. I have tested its discharge capacity readings on the same cell, a Panasonic 2900mah NCR-PF cell, fully discharged first, then fully charged by my Xtar VP2, both occasions @ 1A, and the difference in discharge readings between this charger and my hobby charger, the iCharger 106B+, was 8 mah.


----------



## hammerjoe

Where are the heating sensors located? I dont see them in any pictures of this charger.


----------



## yorab

Ok, so this one clearly has the internal switch.

Has anybody yet tested the 3.7V or 4.35V positions?

BTW, what is the difference between 4.2V and 4.35V?


----------



## HKJ

yorab said:


> Has anybody yet tested the 3.7V or 4.35V positions?



Some people has been using it.



yorab said:


> BTW, what is the difference between 4.2V and 4.35V?



0.15V  LG has some cells that need a 4.35V when charging to get maximum capacity.


----------



## yorab

Thanks HKJ.

So are the charging processes exactly the same between 3.7V, 4.2V, and 4.35V with the exception of maximum voltage? Just trying to learn so that I can make a better decision as to whether I would like to try the other (mostly unproven) voltage settings.


----------



## HKJ

yorab said:


> So are the charging processes exactly the same between 3.7V, 4.2V, and 4.35V with the exception of maximum voltage? Just trying to learn so that I can make a better decision as to whether I would like to try the other (mostly unproven) voltage settings.



I have not tested it on this charger, but it is supposed to be the same.
3.6 volt batteries behaves a little different, they have a large (0.1 to 0.3V) voltage drop when charging terminates, but the charge algorithm is the same.


----------



## hammerjoe

I was wondering for NIMH batteries only which charger works best analysing and charging NIMH's.
This BT-C3100 or the BT-C2000?


----------



## HKJ

hammerjoe said:


> I was wondering for NIMH batteries only which charger works best analysing and charging NIMH's.
> This BT-C3100 or the BT-C2000?



The functions are basically the same but the C3100 has a bit more power and can do stuff at higher current.


----------



## GreatBizarro

The cooling fan just started screaming and sounds like it about to seize up in mine. Been running it quite a bit for the last 2 weeks since I received it. I contacted the support center at gearbest and will see what they suggest.


----------



## GreatBizarro

Just got the replacement fan in yesterday and am back in business. They take care of their customers! Took a while from China to US shipping but the usual 1month.


----------



## hammerjoe

Can someone confirm what capacity is shown during the refresh mode? Is it the Charging capacity or the discharge?
Also when its over after the three passes, does it show the last capacity read (from the last charge or discharge) or the highest reading of the three passes?

The manual says it displays the charging capacity but it could be because of a translation error or something.

From what I read here and elsewhere we want the discharge amount to determine the actual battery capacity right?
The refresh mode by showing the charge capacity forces us to do another cycle by doing the Test mode to determine the real capacity of the refreshed battery.
Is this correct?


----------



## bevangg

yorab said:


> Thanks HKJ.
> 
> So are the charging processes exactly the same between 3.7V, 4.2V, and 4.35V with the exception of maximum voltage? Just trying to learn so that I can make a better decision as to whether I would like to try the other (mostly unproven) voltage settings.



I found out about this hidden switch so took the cover off and put a couple of 4.35 cells to test with the switch set in the middle ie 4.35 position. It did not seem to do anything and the charge ended at 4.2 volts. A bit of a disappointment but nothing seems to have been fried by the test. The Xstar VP2 works well and has an external switch but only cooks two at a time and does not have much functionality or capacity indication.
If the BTC3100 did have this voltage selection function it would be an almost ideal charger.


----------



## markr6

I'm tempted to spend ~$40 on this charger just to test 18650s. I don't use my flashlights very often, but that may actually be justification...how is this affecting my 18650s that sit more than they get used (but not quite "stored")


----------



## spoolin01

The v2.2 is out now, just got one. Does anyone know what the differences with the v2.1 are?

GearBest site suggests some features that are new, but it's not clear these are all new between v2.1 and v2.2 (e.g. 30 sec voltage update).


----------



## keithy

spoolin01 said:


> The v2.2 is out now, just got one. Does anyone know what the differences with the v2.1 are?
> 
> GearBest site suggests some features that are new, but it's not clear these are all new between v2.1 and v2.2 (e.g. 30 sec voltage update).



Tatasal over at BLF asked them directly about the changes. They are fairly minor: http://www.budgetlightforum.com/node/38981. 

I'm looking at picking one up as well.


----------



## ShineOnYouCrazyDiamond

I don't know if anyone has had this problem with the v2.1 charger but every once in a while I'll have a situation where the charger doesn't seem to terminate on a cell. For example I put two eFest 1100mAh 18500 cells in the charger. One charged completely and read full with ~900 or mAh dumped back in. The other 18500 cell kept charging and when I checked it at one point looked to have taken over 2000mAh and was still going. This totally freaked me out. I felt the cell and it wasn't any warmer than the fully terminated one. I pulled it off the charger and checked it with my DMM and the charge voltage was not over 4.2. I've since used the cells, as a pair, and had no issues. 

This experience (which has happened more than once) has definitely shaken my confidence in this charger. The thing is that I like the features that this charger offers. I like seeing how much mAh I've charged/discharged. I like being able to test a cells capacity. I like being able to test internal resistance under load. Etc. I just don't use it that much unless I need to charge a 26650 cell and prefer to use my XTAR charger as it seems to be more reliable and safer with charging.


----------



## Ferdinando

In my personal experience with this charger, I've noted that if the battery IR is high, the measured 
charging current is wrong (more high value than actual).
Maybe so that the charged current value is wrong.
Maybe also your cell (even if at 4.20V) still drain a certain amount of current from charger, and it don't stop to charge it.


----------



## Wiggle

markr6 said:


> I'm tempted to spend ~$40 on this charger just to test 18650s. I don't use my flashlights very often, but that may actually be justification...how is this affecting my 18650s that sit more than they get used (but not quite "stored")




Store them at about 40 percent charge in a cool area to prolong their life.


----------



## hammerjoe

My confidence is also shaken with this charger after my experience wit brand new Duracell Ion Core cells. It terminates them way too early (about half) and I cant figure why.
The cells charge easily in my old lacrosse Bc9009 and they dont get warm while charging, the quick test gives normal IR results.


----------



## spoolin01

keithy said:


> Tatasal over at BLF asked them directly about the changes. They are fairly minor: http://www.budgetlightforum.com/node/38981.
> 
> I'm looking at picking one up as well.


$35.75 now with free shipping, at everbuying.net . I picked one up from them a couple weeks back at a slightly higher price.


----------



## tatasal

spoolin01 said:


> $35.75 now with free shipping, at everbuying.net . I picked one up from them a couple weeks back at a slightly higher price.



Whoohoo...Gearbest has strike back..v2.2 at $ 35.49


----------



## markr6

*V2.2*

I just picked a V2.2 up for $35.49 today at Gearbest. I hope I like it! I'm really interested in the charge test and quick test functions for all my 18650 cells.

Not real excited for a "purplish blue" model, but as long as it doesn't catch fire I can deal with it.


----------



## markr6

*Re: V2.2*

Any v2.2 users have feedback on the Charge Test function showing capacity? Does it seem to be reliable?


----------



## hammerjoe

*Re: V2.2*

I have the 2.1 version and it works well with nimh batteries up to 2000 may. All the 2400 that I have tried so far it fails to charge them to full most of the time.

I hope 2.2 had improved on that.


----------



## Yanix

*Re: V2.2*



markr6 said:


> Any v2.2 users have feedback on the Charge Test function showing capacity? Does it seem to be reliable?



I've tested a bunch of 18650 on my bt-c3100 v2.2 and on my Liitokala lii-300 with 500mA charge / 500 mA discharge (Charge test mode on Opus and Discharge mode on lii-300). My Opus terminates at 4.18 and my Liitokala terminates at 4.23. 

To me it looks like my lii-300 is more accurate than my Opus. 


Opus
Liitokala
Sony SE US18650GR 8A (2600 mAh?) laptop pull
2427
2595
Sony SE US18650GR 8A (2600 mAh?) laptop pull
2488
2617
Sony SE US18650GR 8A (2600 mAh?) laptop pull
2464
2660
Sony SE US18650GR 8A (2600 mAh?) laptop pull
2406
2679
LG LGDB218650 (2600 mAh?) laptop pull
2423
2615
LG LGDB218650 (2600 mAh?) laptop pull
2440
2609
LG LGDB218650 (2600 mAh?) laptop pull
2400
2613
Samsung ICR18650-26H (2600 mAh) new
2674
2823
Samsung ICR18650-26H (2600 mAh) new
2644
2818


----------



## markr6

*Re: V2.2*

All I really got this for is testing capacity on 18650 cells. If I find it to be unreliable, i.e. showing something like '2500mAh' on a fairly new 3400mAh cell, I will be pretty upset.


----------



## hammerjoe

*Re: V2.2*

It looks like I am the only one that had measuring problems with a 3100 so hopefully it remains that way for you.


----------



## Gauss163

*Re: V2.2*



Yanix said:


> I've tested a bunch of 18650 on my bt-c3100 v2.2 and on my Liitokala lii-300 with 500mA charge / 500 mA discharge (Charge test mode on Opus and Discharge mode on lii-300). My Opus terminates at 4.18 and my Liitokala terminates at 4.23. To me it looks like my lii-300 is more accurate than my Opus.



Your C3100 is slightly undercharging, and your LI-300 is slightly overcharging. It makes no sense to call one "more accurate" (that would require some known-accurate capacity test(s) to compare to, e.g. in a professionally calibrated discharge rig).


----------



## markr6

*Re: V2.2*



Gauss163 said:


> Your C3100 is slightly undercharging, and your LI-300 is slightly overcharging. It makes no sense to call one "more accurate" (that would require some known-accurate capacity test(s) to compare to, e.g. in a professionally calibrated discharge rig).



That's what I was thinking. I like that my two current Xtar chargers stop around 4.19v, so I would be OK if my Opus stop at 4.18v. I should have it in a week or so.


----------



## Yanix

*Re: V2.2*



Gauss163 said:


> Your C3100 is slightly undercharging, and your LI-300 is slightly overcharging. It makes no sense to call one "more accurate" (that would require some known-accurate capacity test(s) to compare to, e.g. in a professionally calibrated discharge rig).



Yes, ideally i'd like to compare those capacities to some known-good data, but i don't have access to anything like this. On the other hand when I measure a brand-new 2600 mAh cell from reputable manufacturer and get 26xx on one device and 28xx on the other I feel comfortable saying one is more accurate than the other. Again i'm talking about my two particular devices, maybe others will have different experiences.


----------



## Gauss163

*Re: V2.2*



Yanix said:


> when I measure a brand-new 2600 mAh cell from reputable manufacturer and get 26xx on one device and 28xx on the other I feel comfortable saying one is more accurate than the other. Again i'm talking about my two particular devices, maybe others will have different experiences.



I don't see how you can make any such inference from the data you gave. Please explain the logic you used to derive your claim.


----------



## Yanix

*Re: V2.2*



Gauss163 said:


> I don't see how you can make any such inference from the data you gave. Please explain the logic you used to derive your claim.



Here you go: I got two new Samsung ICR18650-26H cells, manufacturer claims its nominal capacity is 2600 mAh, HKJ tested it under 500 mA discharge as 2616 mAh, my first device gave me 2674/2644 mAh and my second device gave me 2823/2818. To me its obvious that the first device shows measurments closer to cell manufacturer specs and independent test and hence is more accurate.


----------



## markr6

*Re: V2.2*

Thanks for the info. That gives me a little more comfort in that test function on the BT-C3100


----------



## Gauss163

*Re: V2.2*



Yanix said:


> Here you go: I got two new Samsung ICR18650-26H cells, manufacturer claims its nominal capacity is 2600 mAh, HKJ tested it under 500 mA discharge as 2616 mAh, my first device gave me 2674/2644 mAh and my second device gave me 2823/2818. To me its obvious that the first device shows measurments closer to cell manufacturer specs and independent test and hence is more accurate.


 
It seems there is a mixup somewhere. Above you wrote the opposite: "To me it looks like my lii-300 (2nd) is more accurate than my Opus (1st)".


----------



## markr6

I'm starting to wish I just paid the extra $10 to get this on Amazon (2 Day shipping) instead of 25-50 DAYS!!!! from Gearbest.


----------



## Almighty1

markr6, when did you order? I'm in San Francisco, California USA and ordered from Gearbest yesterday, June 12, 2015 for $35.70 with free shipping. Today, I already got a e-mail saying it's been shipped by Netherlands Post Surface Mail and read it can take 25-50 business days which is actually 5-10 weeks as it only counts monday-friday so hopefully it'll get here before the next version is out!


----------



## kreisl

Almighty1 said:


> does anyone know if one can charge size D batteries or not? In any case, glad to read about the SkyRC MC3000, maybe with luck, it will be out before I receive my Opus! LOL. In any case, I might have missed it but what is the largest battery capacity the MC3000 can handle as the NC2500 is 3500mAh and the Opus and MAHA C9000 are both *20,000*.





Almighty1 said:


> so hopefully it'll get here *before the next version* is out!


Hi, afaik i had posted the max capacity counter as *50,000mAh*. It's even higher :devil:, if you set the setting to OFF
Opus and D size batteries, i don't know. Maybe with an adapter. 
MC3000 and D size batteries, no problem.
Too bad that Opus 2.1 users cannot just update the firmware to 2.2 or higher.


----------



## markr6

Almighty1 said:


> markr6, when did you order? I'm in San Francisco, California USA and ordered from Gearbest yesterday, June 12, 2015 for $35.70 with free shipping. Today, I already got a e-mail saying it's been shipped by Netherlands Post Surface Mail and read it can take 25-50 business days which is actually 5-10 weeks as it only counts monday-friday so hopefully it'll get here before the next version is out!



I got the same notification May 29. It had a tracking number with a link to the NP surface mail page, but it just goes to a generic gearbest page. It also doesn't work if I go directly to the NP site. Not a big deal; it will probably arrive next week. Can't wait to test some cells!


----------



## Almighty1

kreisl said:


> Hi, afaik i had posted the max capacity counter as *50,000mAh*. It's even higher :devil:, if you set the setting to OFF
> Opus and D size batteries, i don't know. Maybe with an adapter.
> MC3000 and D size batteries, no problem.
> Too bad that Opus 2.1 users cannot just update the firmware to 2.2 or higher.



I read all posts in the thread quick so might have missed it. Wow, 50,000mAh is a new record without even going to the off setting... 

I did order 2 of the C/D adapters meant for the other AA chargers on Ebay as well. I think Opus might not just fix the software but the hardware as well so people will have the buy the new versions as it seems like their chargers just keep either getting new firmware or the model number is just changed. Is C/D batteries limited to 2 on the Opus and the MC3000 as it seems all of these are originally AA/AAA chargers except they added lithium so it can handle larger batteries.


----------



## HKJ

There is not really any reason for 50000mAh measurement capacity, a D cell is around 10000mAh, with 20000mAh you have enough margin for any reasonable future development.


----------



## Almighty1

markr6 said:


> I got the same notification May 29. It had a tracking number with a link to the NP surface mail page, but it just goes to a generic gearbest page. It also doesn't work if I go directly to the NP site. Not a big deal; it will probably arrive next week. Can't wait to test some cells!



What day did you order since after ordering from them yesterday, I did a search on them and it seems some people wait a week or two before even getting the shipment confirmation so one day seems to be pretty fast. When I clicked on the tracking number, it goes to a generic gearbest tracking page but when I goto the order on their site and click on tracking, it says not found and then there is another link which goes to some Shenzhen China shipping company. The thing is when you check their tracking FAQ, it mentions the 25-50 are business days which is 5 days per week and doesn't include weekends so it can be 5-10 weeks and I have read some people not receiving anything for 45 days which is basically the last day one can actually dispute with Paypal. Good thing with Citicards is that for disputes $75 or under, they will just issue a immediate permanent credit without doing anything so hopefully it doesn't come to that since I made sure to put it on a credit card that doesn't close the billing cycle until July 3 so I have the 60 days from then to dispute if it doesn't show up...


----------



## Almighty1

*Re: When does fan start?*



oKtosiTe said:


> Sunon isn't exactly top-of-the-line, but you could do a *lot* worse with many no-name fans.
> An option if temperature is less of an issue than fan noise is to add a resistor to run it at lower speed. This is what I did with an amplifier; it originally came with a no-name fan that died within months. It was one out of four amplifiers (80,120,240,500W at 8Ω) built with the exact same case. Because of its lower wattage and the high-end fan I replaced the old one with, a lower fan speed was perfectly fine. So now my living room is quiet once more.



Who actually makes the top of the line fans and what size is needed for this charger? I remember in the old days, it's either Panaflo (Panasonic/Matsushita) that was the quietest or Germany's Pabst but I don't know if it comes in those sizes.


----------



## Almighty1

*Re: When does fan start?*

Just a thought, from reading on forums elsewhere, the quality of the capacitors usually play a major role in the performance of the product in question, I see 6 capacitors on the back of the board, not sure if there is any on the other side of the circuit board, would replacing the capacitors which appears to be generic with quality capacitors rated at 105C from United/Nippon Chemi-Con, Panasonic, Rubycon, Nichicon actually make any difference in the performance or quality of the charge to the batteries? I noticed for things like motherboards, it does make a big difference in stability among being able to overclock, etc.


----------



## markr6

*Re: When does fan start?*

Just received mine! Looking forward to testing some 18650 cells. I only plugged it in so far to make sure it's v2.2, it is. The backlight is nice and the buttons seem not as cheap as my La Crosse BC-700.


----------



## Almighty1

*Re: When does fan start?*

Sounds good Mark, when did they ship yours and where are you located? I know mines went out last Monday according to the tracking information but not sure when it'll arrive.


----------



## markr6

*Re: When does fan start?*



Almighty1 said:


> Sounds good Mark, when did they ship yours and where are you located? I know mines went out last Monday according to the tracking information but not sure when it'll arrive.



Shipped 5/29 and received it 6/22 at Ft Wayne, IN. The "purplish blue" they called it is more like a dark gray with a hint of blue.


----------



## Almighty1

*Re: When does fan start?*



markr6 said:


> Shipped 5/29 and received it 6/22 at Ft Wayne, IN. The "purplish blue" they called it is more like a dark gray with a hint of blue.



So basically it took 24 calendar days for you, wasn't as scary as the 25-50 business days that don't count weekends on their site since that would be 5-10 weeks.  Does it basically get delivered by the US Postal Service? I wonder if the ones sold on Amazon is the same color.


----------



## billc501

*Re: When does fan start?*

Ordered mine 6/3 got it today.


----------



## markr6

*Re: When does fan start?*



Almighty1 said:


> So basically it took 24 calendar days for you, wasn't as scary as the 25-50 business days that don't count weekends on their site since that would be 5-10 weeks. Does it basically get delivered by the US Postal Service? I wonder if the ones sold on Amazon is the same color.



Yeah 16 business days, not bad for what it is. Maybe a few more days since USPS is moving on Saturdays. Now that I look at the Amazon photo closer, it appears to be the same color as mine.


----------



## markr6

*Re: When does fan start?*

I ran a CHARGE-TEST last night on four NCR18650B cells. Two (slot 1 & 3) were made March 2013 and two (slots 2 & 4) from May 2014. In general all cells had light-moderate use.

Did I "miss" the capacity reading (discharge cycle) since I went to bed and woke after the charge cycle was complete? Are these numbers displayed below the mA put INTO the cells? Actually now that I look at the display I think I answered my own question; it shows mA*h*, so I'm guessing this is the capacity figure I wanted. Right?


----------



## SilverFox

*Re: When does fan start?*

Hello Markr6,

mAh is current times time. It works both for charging and discharging. Since your display shows Charge, I would guess that it is the amount put into the cells.

If the display showed Discharge, then it would be the actual capacity.

Tom


----------



## markr6

*Re: When does fan start?*



SilverFox said:


> Hello Markr6,
> 
> mAh is current times time. It works both for charging and discharging. Since your display shows Charge, I would guess that it is the amount put into the cells.
> 
> If the display showed Discharge, then it would be the actual capacity.
> 
> Tom



That's what I was worried about. Dang it!! I could have stayed up an extra 30 minutes or so and I probably would have caught it. I think I'll run it again and hopefully catch it at work.


----------



## kreisl

*Re: When does fan start?*

i sold my BT-C3100's and i cannot recall off the top of my lil head.

what does the user manual say about the CHARGE-TEST function?


----------



## markr6

*Re: When does fan start?*



kreisl said:


> i sold my BT-C3100's and i cannot recall off the top of my lil head.
> 
> what does the user manual say about the CHARGE-TEST function?



Not much.I read it over and over last night but didn't help.

Test mode: Checks the present capacity of a rechargeable 
battery. The maximum capacity is determined by discharging 
the rechargeable battery after it was fully charged. If the 
maximum capacity is 
much lower than the rated capacity 
then it may reach the end of its lifetime

But WHEN does it display the capacity? I'm guessing after the discharge all the way up until it is finished charging? Or maybe the entire time after discharging and after the charge?


----------



## markr6

*Re: When does fan start?*

I'm not trusting the QUICK TEST function to measure resistance very helpful. Numbers are all over the place. The manual says they will vary from slot to slot and even after separate tests though. I'll also need to remember this:

Due to the construction reason, there is around 30milliohm contact resistance from the charger itself, and this resistance is calculated together with battery internal resistance. It should be deducted from the reading to get a more accurate battery resistance reading.


----------



## markr6

*Re: When does fan start?*

GOT IT! All 4 cells just finished discharging within a few minutes of each other while doing another CHARGE-TEST. So you can view the capacity anytime before the charging finishes. This looks much better:






LOVE this charger!! The fan runs pretty much all the time but it's very quiet like most laptops. Cells got slightly warm while discharging at 1000mA, but not bad at all.


----------



## hammerjoe

*Re: When does fan start?*

Charge/test will show "----" until the discharge mode is completed and then on the v2.1 would show the discharge capacity.


----------



## hammerjoe

*Re: When does fan start?*



markr6 said:


> I ran a CHARGE-TEST last night on four NCR18650B cells. Two (slot 1 & 3) were made March 2013 and two (slots 2 & 4) from May 2014. In general all cells had light-moderate use.
> 
> Did I "miss" the capacity reading (discharge cycle) since I went to bed and woke after the charge cycle was complete? Are these numbers displayed below the mA put INTO the cells? Actually now that I look at the display I think I answered my own question; it shows mA*h*, so I'm guessing this is the capacity figure I wanted. Right?




This looks like you are in Charge mode only and not CHARGE/TEST. The "test" word would display if that was the case.
When it finishes it will display FULL and the capacity of the charge.


----------



## markr6

*Re: When does fan start?*



hammerjoe said:


> This looks like you are in Charge mode only and not CHARGE/TEST. The "test" word would display if that was the case.
> When it finishes it will display FULL and the capacity of the charge.



This was the CHARGE-TEST mode, but AFTER it was done charging. It says FULL, but you can toggle thru to see the mAh for a couple seconds. In my post above, you can see the "TEST" still shows since they are not fully charged yet.

It all makes sense now. Not a big deal that the DISCHARGE figures go away since it takes hours to charge...but if you're doing it overnight like I did, you're out of luck.


----------



## markr6

*Re: When does fan start?*

Finished my second CHARGE-TEST. Great charger!! Nice consistent values all around the *3400mAh *rating on these cells too.

I did a few quick tests as well (milliohm):
74 100 76 83
74 110 75 80
81 121 78 82
79 114 77 78
77 107 77 78

Not sure what's going on with the second one at 100+. It's one of the newer cells, not used heavily or stored in extreme temps. I swapped slot 1 with slot 2 and it's showing around 90 now. Good enough estimate I guess. Like the manual suggests, simply moving them around in the cradle can alter the readings.


----------



## Almighty1

*Re: When does fan start?*

From what I read, Opus/La Crosse are supposedly the same chargers since NLee is well known, this is his guide on the different modes for the BC chargers which this is based on:
http://www.amazon.com/review/RK62EG...web-20&linkCode=ur2&camp=1789&creative=390957


----------



## tatasal

*Re: When does fan start?*



markr6 said:


> This was the CHARGE-TEST mode, but AFTER it was done charging. It says FULL, but you can toggle thru to see the mAh for a couple seconds. In my post above, you can see the "TEST" still shows since they are not fully charged yet.
> 
> It all makes sense now. Not a big deal that the DISCHARGE figures go away since it takes hours to charge...but if you're doing it overnight like I did, you're out of luck.



The figures on display can be confusing, so if I intend to get a discharge capacity of my cell, I don't use the Test mode, I just charge it using the Charge mode, rest the cell for an hour, then discharge it using the Discharge mode, after which you can see the capacity displayed is that of its discharge capacity.


----------



## markr6

*Re: When does fan start?*



tatasal said:


> The figures on display can be confusing, so if I intend to get a discharge capacity of my cell, I don't use the Test mode, I just charge it using the Charge mode, rest the cell for an hour, then discharge it using the Discharge mode, after which you can see the capacity displayed is that of its discharge capacity.



Yes I thought about this last night. That seems like the best option. I did the TEST CHARGE since I was paranoid about leaving a cell at 2.9v, but I don't think it would hurt it unless I left it like that for days or weeks. I'll definitely do this from now on to keep it simple.


----------



## tatasal

*Re: When does fan start?*



markr6 said:


> Yes I thought about this last night. That seems like the best option. I did the TEST CHARGE since I was paranoid about leaving a cell at 2.9v, but I don't think it would hurt it unless I left it like that for days or weeks. I'll definitely do this from now on to keep it simple.



Actually, the Test Mode is actually beneficial only to niMh cells, as they are akin to the Refresh mode of the C9000, and not to li-ion cells. It just hasten its early demise for every cycle of the Test/refresh mode.


----------



## markr6

*Re: When does fan start?*



tatasal said:


> Actually, the Test Mode is actually beneficial only to niMh cells, as they are akin to the Refresh mode of the C9000, and not to li-ion cells. It just hasten its early demise for every cycle of the Test/refresh mode.



That's a good point. Since these cells are still doing great after 2+ years, I'm not so worried about checking the capacity now. Seems like a once/year thing just for peace of mind.


----------



## Almighty1

*Re: When does fan start?*

While we're on the subject and I still haven't received my charger from GearBest.com yet, I am using a Maha MH-C204F charger for the last 10+ years which charges in pairs and I have some questions on which modes I should use to get the maximum capacity. 

1) I have 8 MAHA PowerEx 1550mAh NiMH AA batteries which still works but a few of them seem to go from bad to full on a battery tester in a short amount of time. Do I use the discharge/refresh on this or do I do the charge/test and the discharge to see what the capacity is first before doing the discharge/refresh as it may be just the charger not charging the batteries property since it's dual channel.

2) I have some new Radio Shack 2500mAh and GP AA NiMH that had been here for 5-6 years but it will not even get the red light on the charger to go on unless I use 2 paper clips and jumpstart the batteries by using a fully charged good battery and connecting the + to + and - to -, it will then charge but I noticed that on some of them, it will charge a few hours except when using the batteries, it seems to go from good to bad on a battery tester to bad in a short timeframe. 

3) Similar to #2 above except some batteries seems to be completely dead and can charge to full capacity in 15-20 minutes, or at least both the charger and even the battery testers seems to think that way. 

In those scenarios, which modes should I be using? or should I really do a discharge/refresh on all batteries even the Eneloop Pro XX's that are still unopened in the package from 2014 first before doing the charge/test and then the discharge? or should it be the other way around, charge/test, discharge and if the capacity isn't good, then do the discharge/refresh?


----------



## HKJ

*Re: When does fan start?*

Generally it is a good idea to do a charge/test on new batteries and when you suspect that a battery is getting bad. If it is considerable below the initial test (Below 70%), you either throw it out or move it to applications with a very low current requirement.

If the charge/test is a bit low you can try a discharge/refresh and see if the battery gets better (This will depend on why it is low in capacity).

The quick/test is a simplified method to check the status of the battery, a high value means a bad battery (High depends on what the values is on a new battery in the same size).

Batteries that charges/discharges very fast are probably ready for recycling.


----------



## Almighty1

*Re: When does fan start?*

Thanks HKJ. The batteries that charges/discharges very fast are actually batteries that I had never even used once before so it required a jumpstart to get it going and then it charges fast too but what is weird is why the chargers and the battery tester which are meant for alkaline batteries would see it as in charge capacity since it's in the green area on the tester - can batteries actually trick the battery tester http://www.amprobe.com/amprobe/usen...ters-and-analyzers-/amp-bat-100.htm?pid=73175, maybe it just takes a discharge/refresh to get it working correctly. Is quick/test the same as charge/test? I never really had many rechargeable batteries other than the 8 MAHA's and before that, was doing Eveready NiCd in 1994 and in the 1980s, GE NiCD. Seems like all NiCD's end up leaking and then have the white stuff on top within years. I remember the GE NiCD which were later Sanyo/GE all were pretty easy to get a spark as the hole was in the middle.


----------



## Rick NJ

*Re: When does fan start?*



markr6 said:


> I ran a CHARGE-TEST last night on four NCR18650B cells. Two (slot 1 & 3) were made March 2013 and two (slots 2 & 4) from May 2014. In general all cells had light-moderate use.
> 
> Did I "miss" the capacity reading (discharge cycle) since I went to bed and woke after the charge cycle was complete? Are these numbers displayed below the mA put INTO the cells? Actually now that I look at the display I think I answered my own question; it shows mA*h*, so I'm guessing this is the capacity figure I wanted. Right?



A *few things jumbo into a single reply* here:

I recently got the Opus BT-C3400 (aka BT-3100 with *v2.2* software according to some forums). It has almost identical user interface to the LcCrosse BC700 I've been using for over a year.

(1) *Missing the number because of not staying and watch - I handle that with...*

When I first got my LaCrosse BC700, I was rather unsure about the (meaning of) readings. I put a *USB cam* to work on time-lapse. *If you don't want to stay up to watch, the USB CAM is particularly useful* with the DISCHARGE-REFRESH mode when it keeps (re)cycling. You get to see the capacity-out for each cycle in your captured photos.

(2) *Observed differences (with LaCrosse) - interesting but not meaningful*

The LaCrosse BC700 (NiMH only) DISCHARGE-REFRESH mode will keep cycling until the *capacity stops increasing*. It assumes as the NiMH exercise, you regain some of the lost capacity. The BT-C3400 DISCHARGE-REFRESH mode does it for *3 cycles regardless of capacity outcome*. In the case of BC700, you actually *see the output mAH summing up as it discharges* whereas the BT-C3400 shows dashes until the discharge cycle is done. Also, the BC700 discharge at 1/2 charge current. So, charging at 700mA means discharge at 350mA.

(3) *Is the number right?*

So far, the BT-C3400 appears to work well. However, with my 18650's, the discharge capacity reported has a delta of + 10 to 20% (higher than expected) compare to my prior (pre-BT-C3400) method. My standard way of measuring mAH output is with the INA219 current-sensor. I discharge with a fixed resistor, driving/logging the INA219 with an Arduino at 1 second interval, and let Excel calculate the mAH at different stop voltage. I am not sure if I had a bug in my prior method or is the BT-C3400 wrong. Or perhaps the pulsed discharge actually increased the total-output as the cell is given a short time to recovery just a little during pulse-low. I have to check closer yet and hasn't done so. It could even be a simple measurement error and no delta exists at all. Since I am using output mAH as a relative number to sort my cells, this hasn't yet rise in priority.

Since the BT-C3400 is a pulse-charger, logging is a bit difficult. I have logging DMM, Arduino (on board ADC), external ADS1115 ADC, and INA219 current sense. None of them really function well with the pulse instead of a constant Volt or Current. I have to rework those a bit before I can use my prior tools to measure the BT-C3400 directly.

(4) *A quirk*

One quirk I noticed - I ran TEST-CHARGE on a pair of NiMH, it got to 0mA and stayed for a long while before it considered charge completed and start the discharge. I think it was probably below 0.5mA and rounding down to zero but current is still flowing. Still, looking at the *charging at 0mA* is uncomfortable.


----------



## kreisl

*Re: When does fan start?*



Rick NJ said:


> (3) *Is the number right?*
> 
> So far, the BT-C3400 appears to work well. However, with my 18650's, the discharge capacity reported has a delta of + 10 to 20% (higher than expected) compare to my prior (pre-BT-C3400) method. My standard way of measuring mAH output is with the INA219 current-sensor.



Rick, one indirect way of finding out which value, pre-BT or BT, is the correcter one is by trying to reproduce datasheets of HQ battery manufacturers as closely as possible. For example the NCR18650B has a nominal capacity of 3350mAh, or minimum capacity of 3250mAh at 25°C and 2.50V cut-off and 0.2C discharge rate, i.e. 0.2*3250mA = 650mA.

Get a new fresh NCR18650B, charged it up, discharge it with the 700mA setting down to 2.50V with the BT, and look at the result. Should be 3250-3350mAh at 25°C (warm room!). If the cut-off voltage of BT is higher, e.g. 2.90V i dunno, then you should get even less than that. And also less because 700mA is higher than 650mA.

Anything over 3400mAh is imho a clear indication that the BT shows higher mAh's than reality. How much higher?

In order to determine how much higher the BT shows mAh's, one needs to mimick its discharge program (-0.70A, 2.90V, 25°C) with an accurate reference charger-analyzer


----------



## Almighty1

*Re: When does fan start?*

I received my Opus BT-C3100 v2.2 from gearbest.com yesterday on July 3, 2015 that was shipped June 15, 2015 via Netherlands Post Surface Mail so it took 18 days. Will post after I use it a bit.


----------



## markr6

*Re: When does fan start?*

My v2.2 is still working great. I've been charging 3x18650 and 4x18650 often and the charge seems nice and consistent every time. Cool batteries and charger at 700mA and 1000mA.


----------



## Almighty1

*Re: When does fan start?*

I've been trying the discharge refresh mode on AA batteries which are MAHA 1550mAh and even brand new batteries which are Radio Shack Premium 2500mAh which was still sealed in the package for a few years and they all report 200-1000mAh in capacity using 1000mAh charge and 700mAh discharge unless there is a better way to do the reconditioning of the battery manually.


----------



## markr6

I was always too impatient to try the refresh mode on my BC700 and now this one. I usually do a charge-test and call it done. Those sure are low numbers though; sorry I can't offer any help. Maybe charge them in another charger, then just do a discharge on this one.


----------



## MidnightDistortions

*Re: When does fan start?*



Almighty1 said:


> I've been trying the discharge refresh mode on AA batteries which are MAHA 1550mAh and even brand new batteries which are Radio Shack Premium 2500mAh which was still sealed in the package for a few years and they all report 200-1000mAh in capacity using 1000mAh charge and 700mAh discharge unless there is a better way to do the reconditioning of the battery manually.



Try using a lower current charge/discharge rate and see if that helps.


----------



## PCH

My self I have the nightcore D4 but it's so slow at charging


----------



## Almighty1

I'll try a slower rate, I know the MAHA's might be at the end of life as those were my always in used batteries since the mid-90's but the Radio Shack ones are basically still new in the package that was bought in 2008/2009, I also have a GP 2100mAH industrial rechargeable battery that came with my Microsoft mouse except I never used it while using the MAHA instead.... Other than the MAHA's, both the Radio Shack and the GP requicked jump starting the battery with paper clips from another battery before the previous MAHA C201F charger will even see the battery.


----------



## markr6

I just tried charging a single 18650 at 1500mA setting. It starts charging, but when I cycle thru the display, the current is displayed as approximately 960mA-1005mA (it fluctuates). Is this possibly due to the cell being somewhat full to begin with (around 4.00v)?


----------



## HKJ

markr6 said:


> I just tried charging a single 18650 at 1500mA setting. It starts charging, but when I cycle thru the display, the current is displayed as approximately 960mA-1005mA (it fluctuates). Is this possibly due to the cell being somewhat full to begin with (around 4.00v)?




Yes, current will start to drop when voltage hits 4.2 volt and just starting to charge at 4.0 volt will get voltage up to around 4.2 volt.


----------



## markr6

Can I use this car adapter for my Opus? 12v, 3A so I'm assuming it would be OK.

http://www.ebay.com/itm/12V-3A-Car-...1000-1000H-1000HA-1000HD-1000HE-/351138229497


----------



## HKJ

markr6 said:


> Can I use this car adapter for my Opus? 12v, 3A so I'm assuming it would be OK.
> 
> http://www.ebay.com/itm/12V-3A-Car-...1000-1000H-1000HA-1000HD-1000HE-/351138229497



I wonder why it is so big, maybe there is some filtering in it. Usual this is a good thing, but it might give problems with the current spikes on the Opus.


----------



## MidnightDistortions

*Re: When does fan start?*



Almighty1 said:


> While we're on the subject and I still haven't received my charger from GearBest.com yet, I am using a Maha MH-C204F charger for the last 10+ years which charges in pairs and I have some questions on which modes I should use to get the maximum capacity.
> 
> 1) I have 8 MAHA PowerEx 1550mAh NiMH AA batteries which still works but a few of them seem to go from bad to full on a battery tester in a short amount of time. Do I use the discharge/refresh on this or do I do the charge/test and the discharge to see what the capacity is first before doing the discharge/refresh as it may be just the charger not charging the batteries property since it's dual channel.
> 
> 2) I have some new Radio Shack 2500mAh and GP AA NiMH that had been here for 5-6 years but it will not even get the red light on the charger to go on unless I use 2 paper clips and jumpstart the batteries by using a fully charged good battery and connecting the + to + and - to -, it will then charge but I noticed that on some of them, it will charge a few hours except when using the batteries, it seems to go from good to bad on a battery tester to bad in a short timeframe.
> 
> 3) Similar to #2 above except some batteries seems to be completely dead and can charge to full capacity in 15-20 minutes, or at least both the charger and even the battery testers seems to think that way.
> 
> In those scenarios, which modes should I be using? or should I really do a discharge/refresh on all batteries even the Eneloop Pro XX's that are still unopened in the package from 2014 first before doing the charge/test and then the discharge? or should it be the other way around, charge/test, discharge and if the capacity isn't good, then do the discharge/refresh?



I missed the part with the Radioshack batteries, are they the Enercells? Chances are youll need to refresh them or break them in by having them sit on the charger for 16-24 hours at around @ 50-100mA then discharge them and repeat the recharge top off depending on how much capacity you gained plus how much charge was put back into the battery, you may only need to let the cells trickle charge for 8 hours. I didnt do this with my lacrosse cells and as a result they seem to have lost permanent capacity and will only charge properly at 200 mA.


----------



## Beacon of Light

*Re: When does fan start?*

Never knew this charger was even available. Sounds great. It kind of looks like a direct copy of the infamous firestarter Lacrosse BC-900 but yet I haven't read anything mentioning the similarities which is odd as it looks like an exact copy especially the LCD display. 

Anyhow, I see people have issues with the fans failing and that they sell replacements for these units. Are the fans a standard laptop size mini fan? I think I have a box of about 12 of them somewhere.

Also if these are related to the LaCrosse chargers (I read this company previously made the Accupower chargers) then how would one feel assured the problems of the old BC-900's that melted batteries and went on runaway meltdown wouldn't happen to this charger considering these have way higher charging currents as well as voltages?

One last thing, will the compression sliders get tight enough to charge an N-cell without any sort of adapter? Thanks.


----------



## ven

*Re: When does fan start?*

They are a great charger and from gearbest not much over $30(or was a few weeks back)......bargain.

My fan is noisy,quite loud but not failed and in use daily for up to 8hrs a day! They are on v2.2 now to aparently fix some niggles and even re-named it the BTC-3400 which looks exactly the same. Think i kind of distraction for the issues of previous versions........could be wrong,just an assumption(no evidence).

Cant help on the N-cell side, quick pic for you to show gap in the bays for maybe an idea




Would say 33mm as the + sticks out about 1.5mm ish


----------



## Beacon of Light

*Re: When does fan start?*

yeah thanks for the effort on the N cell thing. I saw a review maybe the beginning of this thread, but the space is 32mm and an N cell is 30.xx mm so too short, so I will need a spacer or some sort of adapter.


----------



## ven

Xtar do spacers,these can be screwed into each other to increase the spacer size(wp6 II has them). You would probably only need one.


----------



## HKJ

ven said:


> Xtar do spacers,these can be screwed into each other to increase the spacer size(wp6 II has them). You would probably only need one.



For a short spacer you can use a coin or a nut or a lot of other metallic stuff.


----------



## ven

Good point/idea


----------



## Beacon of Light

I've read the Opus charger shipping from GearBest takes up to 20 days. I ordered on September 17th so I guess I'm still within the range. But I saw people mentioning it was shipping from The Netherlands, but my order had a picture of a package shipping from China via China Post. Does GearBest ship from both Netherlands and China?


----------



## markr6

Beacon of Light said:


> I've read the Opus charger shipping from GearBest takes up to 20 days. I ordered on September 17th so I guess I'm still within the range. But I saw people mentioning it was shipping from The Netherlands, but my order had a picture of a package shipping from China via China Post. Does GearBest ship from both Netherlands and China?



Yeah mine was probably 20 business days; I think close to a solid month IIRC. They sent it NL Surface post, but I remember seeing chinese or some other writing all over the label. Not sure what that's all about.

While I'm here, I'll say mine is still doing a great job. Still maxing out around 4.16v. Not bad, but starting to wish it was closer to 4.20v. I used to take my cells off at 4.15, but I don't really care anymore


----------



## ven

Yes from europe or china warehouse, i am sure i picked the EU option and it arrived pretty quick(week or so).

Well worth the wait either way!

Mine is still used daily from the day i received it , for ~8hrs mon-fri and all day sat/sun.............issue free............


----------



## kosPap

here are my observations of the v2.2 of this charger:

*1. The charger will stop charging old batteries.*
Obsereved with batteries with internal resistance of 150+mOhms. It happens from a certain point on during the charging process. Lowering the charge current wil restart it, to be stoped again latter.
I do not know how the charger monitors this, but i think it is agood thing.

*2. The hidden alternate chemistry switch WORKS!
*I am charging 4.35 batteries at the moment. The process is this. You access the PCB on the bottom and switch the sliding switch to the 4.35 mark.
(see HKJ's pic) Upon inserting the batteries you will get a "full" indication if they are close to 4.2Volt (like mine were). Then you initiate charging again. Charging will stop at 4.34V (per charger's screen).
I do not know how the charger will act if you load a 4.35 battery when it is less than 4.2. Did not ahve any to try. Maybe it will stop to be re-started, maybe it will not.
S far i have been trying to beat the 4.35 termination by re-initiating charging repeatedly, with no success.


----------



## Beacon of Light

Still waiting for my order from Gear Best. Ordered 9/17 and today is 10/18. I know the Gear Best shipping "estimate" says 18-25 BUSINESS days, so by the end of this next week will be the high side of that estimate. Has anyone from the US had to wait over a month for this before or am I the first?


----------



## thslw8jg

I received my charger in just under 3 weeks.


----------



## ven

I would say pretty imminent mr light, do you have tracking? could open a ticket and find out exactly when shipped and by who............just thoughts.

Would give it 4 -5 weeks from post date,usually 3-4 weeks i would say is the norm.


----------



## Beacon of Light

ven said:


> I would say pretty imminent mr light, do you have tracking? could open a ticket and find out exactly when shipped and by who............just thoughts.
> 
> Would give it 4 -5 weeks from post date,usually 3-4 weeks i would say is the norm.



I tried opening a ticket a week ago but they said it was shipped unregistered China Post so there is no tracking. I may be screwed, but I saw others on here opted for free shipping from Gear Best and still received their orders so I figured it was safe.


----------



## ven

Yes , I am yet to have an order not turn up! 

My biggest disgruntlement is buying then showing re-stock for weeks later. So it's over a month before it even ships!!! I know I may be daft but I am not daft enough to order something that's 5+ weeks wait for stock...... 
I would say given the time next week will be the week.

I at the time had the choice of EU warehouse and the price did not go up! Mine took or what it seemed to take ,around a week or so to arrive. Other items 4 weeks or so.....


----------



## MAD777

Gearbest takes forever. It took over 3 weeks for a couple of batteries. I've been waiting for a LiitoKala charger for almost 3 weeks. No sign of it yet.


----------



## ven

I find banggood the same and both have adopted similar practices of showing stock, then no stock days later and XXXX when expected back. 

Now i am more specific and only order if in no rush and already have back up...........in short if i need quick i avoid the said places.

Issues have always been resolved of past, nothing wrong there for me, just had enough now with inaccurate stock levels. Took me weeks to wait for my ti cooyoo at BG,then more weeks for delivery.........The BLF a6 is cancelled now and after reading various QC issues i am fine with it.

I have 8 cells,4 just posted now from the 25th Sep, then next 4 to go out Mon or Tue again from an order on the 25th Sep !!!!. My best is the TFV4 tank, that wont even be posted till the 31st Oct...........from an order again around the 25th Sep showing stock!!

I digress, hold tight,the charger is actually worth the wait


----------



## vk4akp

Hi, I'm wanting to buy a good Li-Ion Cell charger / analyzer. 
Is this model still the best option on the market?

Some features I would like if possible. 

- 12VDC supply (For off grid use). 
- Computer connectable for analysis & firmware updates etc either via WiFi (preferable) or Bluetooth, Ethernet, or USB. (Order of preference). 

Oh, does anyone know the website for this company?
Any info appreciated. tnx!  
.-.-.


----------



## HKJ

vk4akp said:


> Hi, I'm wanting to buy a good Li-Ion Cell charger / analyzer.
> Is this model still the best option on the market?



Yes, but the SkyRC MC3000 that is released soon will be more advanced.


----------



## akhyar

vk4akp said:


> .....
> - Computer connectable for analysis & firmware updates etc either via WiFi (preferable) or Bluetooth, Ethernet, or USB. (Order of preference
> .-.-.



Maybe you can wait for th SkyRC MC3000 that will be launched soo


----------



## vk4akp

Thanks, Yes I will definitely wait. 

The SkyRC MC3000 looks much better! 

I found a review in CandlePowerForums. Seems it's been in development for some years?

Any idea on price and where to buy? I am in .AU (.AU plug??) 

.-.-.



akhyar said:


> Maybe you can wait for the SkyRC MC3000 that will be launched soo


----------



## akhyar

Maybe you can post your questions at the MC3000 thread, but from what was mentioned by "squirrel", definitely more than 50 bucks


----------



## HKJ

vk4akp said:


> I found a review in CandlePowerForums. Seems it's been in development for some years?



Yes, it has promised a long time ago.



vk4akp said:


> Any idea on price and where to buy? I am in .AU (.AU plug??)



Their small model (NC2500) is $70, this one is much more advanced. I doubt it will be below $100
There is nowhere you can buy it yet, but search for NC2500, it will probably be in the same shops.


----------



## vk4akp

Yep, sounds the go. I definitely want one. 
As long as they are under AU$130ish + post I'm in. 

I'll jump across to the other thread. 

Thanks guys!
.-.-.


----------



## lumen aeternum

>Generally the peak charge and discharge current for LiIon are a bit high, I would have preferred constant current, instead of the pulsing.
The user interface is fairly easy to use, but it may take a some time to learn what the different modes do.

The conclusion must be that it is a good battery analyzer, but for normal charging I will still prefer a charger with non-pulsing CC/CV charging.
>

Is there a thread that discusses the pros & cons of pulse vs non pulse charging?


----------



## Beacon of Light

Well the back and forth messages between myself and GearBest have come to a puzzling conclusion. They responded today saying I can get 50% of the cost refunded. I paid in full 100% and never received the charger I ordered on 9/17/15 so now I have to settle for only getting 50% refunded to me after all this time? I can't believe I'm the first one getting screwed like this if this is their policy. I told them I want the charger I paid for and if it was lost in shipment that's not my fault. My guess is since it was mailed unregistered someone over at China customs probably got their hands on it around the end of September and it never made it out of the country. So pissed after waiting all this time and this is the outcome.


----------



## markr6

Beacon of Light said:


> Well the back and forth messages between myself and GearBest have come to a puzzling conclusion. They responded today saying I can get 50% of the cost refunded. I paid in full 100% and never received the charger I ordered on 9/17/15 so now I have to settle for only getting 50% refunded to me after all this time? I can't believe I'm the first one getting screwed like this if this is their policy. I told them I want the charger I paid for and if it was lost in shipment that's not my fault. My guess is since it was mailed unregistered someone over at China customs probably got their hands on it around the end of September and it never made it out of the country. So pissed after waiting all this time and this is the outcome.



50% that's crazy! Too bad they're about $50 on Amazon. I keep one in my cart just to try and catch a possible price break. Hasn't happened yet, but if they get cheap I'll pick up a second charger there.

I'm still using mine a lot. It's doing a great job!


----------



## akhyar

Beacon of Light said:


> Well the back and forth messages between myself and GearBest have come to a puzzling conclusion. They responded today saying I can get 50% of the cost refunded. I paid in full 100% and never received the charger I ordered on 9/17/15 so now I have to settle for only getting 50% refunded to me after all this time? I can't believe I'm the first one getting screwed like this if this is their policy. I told them I want the charger I paid for and if it was lost in shipment that's not my fault. My guess is since it was mailed unregistered someone over at China customs probably got their hands on it around the end of September and it never made it out of the country. So pissed after waiting all this time and this is the outcome.



That's the standard reply from Gearbest if your missing item was not insured or tracked.
I've also missing package from GB without tracking and I told them if they don't refund me 100%, I'll file a PayPal claim and take my chance with PayPal


----------



## Beacon of Light

akhyar said:


> That's the standard reply from Gearbest if your missing item was not insured or tracked.
> I've also missing package from GB without tracking and I told them if they don't refund me 100%, I'll file a PayPal claim and take my chance with PayPal



Yeah, I'm done screwing around with GB and just contacted Paypal and they should get my money refunded. I just have to wait 10 days now.


----------



## adventurema

*This is my first entry into the world of rechargeable batteries. I just ordered several packs of AA and AAA Eneloops. Now I'm in need of a charger. I don't think I will go much beyond the AA/AAA sizes, maybe a few 18650's. I'm willing to spend a little more in robust a charger/analyzer, but not full featured like the SkyRC.*

*I'm considering the La Crosse BC-1000, Maha MH-C9000 and the Opus BT-C3100 v2.2. However, after 3 days of reading posts and reviews, I'm in a state of paralysis from the overwhelming information posted on these chargers.*

*Would appreciate any help in determining if the Opus is still considered to be the best all-around charger/analyzer for my situation, or what your pick would be.*
*Thanks for your help!*


----------



## ven

I cant say best , but i have been using mine daily since bought,charging mainly 18650 cells and occasional AA/AAA loops. Does everything i need and cant fault it for what i paid, personally i can recommend the v2.2 as an all round charger

To put it another way, if it went missing ,i would order another the same day without thought.............


----------



## akhyar

ven said:


> To put it another way, if it went missing ,i would order another the same day without thought.............



+1.
same here ven


----------



## adventurema

Thanks for your feedback ven and akhyar! I've ordered the Opus charger and my Eneloops just arrived.


----------



## Beacon of Light

Well I just got my refund from Paypal for the order from Gear Best. Now that I am starting over again from scratch, I can't see how to order one from GB that will guarantee a tracking number this time so I can cover my tracks. All I see available is the same "free shipping" I had last time that is untrackable. Any help, I'd really like to get this charger sometimes this year...


----------



## tripplec

*Don't order from Banggood.* I ordered a Stainless penlight and it stopped working a few months later. Sorry, no warranty and didn't care. I never had trouble with eBAY sellings from China etc. If there is a problem they do their best to correct it. You just have to wait for shipping a while some arrive faster than others. But nothing lost yet and always arrive.


----------



## chewy78

Beacon of Light , I got my Opus BT-C3400 v2.2 from Rdana on eBay if that helps. That person is a US seller in the states. It cost a little more than 32-35 dollars but you should get good service with a tracking number.


----------



## Gauss163

chewy78 said:


> Beacon of Light , I got my Opus BT-C3400 v2.2 from Rdana on eBay if that helps. That person is a US seller in the states. It cost a little more than 32-35 dollars nut you should get good service with a tracking number.



He's also got a sale on the (same?) BT-C3100 v2.2 for $37.78. Also other US eBay sellers offer it around $36.


----------



## Beacon of Light

chewy78 said:


> Beacon of Light , I got my Opus BT-C3400 v2.2 from Rdana on eBay if that helps. That person is a US seller in the states. It cost a little more than 32-35 dollars nut you should get good service with a tracking number.



Well based on price I think I'd stay with GB but just not sure if their Priority Direct Mail / America Direct Express (3-7 days) includes the tracking info. I know the Flat Rate doesn't unless you pay extra separately. When I read their shipping rates it doesn't say untrackable so should I assume it includes tracking? I could do the Flat Rate shipping and over $40 the tracking says $0.00 or free (Im ordering 2 of the Opus chargers) but I'll be damned to wait 10-25 business days all over again.

I tried using the online chat but it says no agents available. Do they only do online chat during M-F?


----------



## markr6

Bouncing around $38-41 on Amazon right now. 2 day free shipping with Prime.


----------



## Prepped

My BT-C3100 v2.2 just arrived from Gearbest. Seems well built, and will be more than adequate for my needs.


----------



## THE HOGG

Can someone tell me if this charger will charge more than one C size battery at a time? I too have read enough posts to make me cross eyed. I think this seems like the best charger for me but want to make sure on the C issue as I had a Nitecore charger and it would only fit one at a time. I use C's in my hunting cameras so it is important to me to not have to spend days on end trying to charge 12 of them. I will use it for C's and 16340 batteries, am I making the right choice?


----------



## HKJ

THE HOGG said:


> Can someone tell me if this charger will charge more than one C size battery at a time?



It will take two.


----------



## THE HOGG

HKJ said:


> It will take two.



Thank you.


----------



## usrnam

I see the BT-C3100 V2.2 is on sale for $33._92_ (US Plug) includes free shipping to US and other countries. There is also a plug EU and UK plug version.

For less than $2.00 I'm able to add either tracking or choose an alternate shipping

Priority Direct Mail & America Direct Express 3 - 7 business days 



http://www.gearbest.com/chargers/pp_173012.html?vip=94353


----------



## usrnam

I saw an article online with pics of how a person built a 4 x D cell adapter for the Opus CT-3100. The person using it and says it works just fine to charge 4 x D cells.


----------



## chewy78

THE HOGG said:


> Can someone tell me if this charger will charge more than one C size battery at a time? I too have read enough posts to make me cross eyed. I think this seems like the best charger for me but want to make sure on the C issue as I had a Nitecore charger and it would only fit one at a time. I use C's in my hunting cameras so it is important to me to not have to spend days on end trying to charge 12 of them. I will use it for C's and 16340 batteries, am I making the right choice?


 i can squeeze 3 c cells on mine.


----------



## chewy78

usrnam said:


> I saw an article online with pics of how a person built a 4 x D cell adapter for the Opus CT-3100. The person using it and says it works just fine to charge 4 x D cells.



i believe that is on BLF.


----------



## ShineOnYouCrazyDiamond

Here's a question for everyone who uses the charger to test internal cell impedance. Do you find the testing to be accurate and repeatable? I do not.

I can take the same cell and put it in the four slots for four reading and get four completely different results. Then I can take the same battery and do a bunch of readings in the same slot and still get multiple different results. I realize the readings are somewhat based on how good a contact you have and any small resistance points will make a difference but to get reading anywhere between 50 mOhms to 100 mOhms for the same cell seems like way to large a spread.


----------



## markr6

ShineOnYouCrazyDiamond said:


> Here's a question for everyone who uses the charger to test internal cell impedance. Do you find the testing to be accurate and repeatable?



Absolutely not. I can get anything from 40-100 on a brand new, cell with a known low IR. I believe selfbuilt mentioned the same things you did in his review about how the contact surface affects the reading.

I like it as an estimate, but not as an actual reading. For example, I had an Eagletac 3400mAh cell in my car for over a year charged to 4.10v or so with almost no use. After that time, it held voltage really well, but the IR test showed 200milliohm! Compare that to the exact same cell kept indoors, reading around 90milliohm.


----------



## ShineOnYouCrazyDiamond

Interesting thing is that internal impedance won't really show you how well a cell can hold it's voltage. You can have a brand new cell with high impedance that will hold voltage just fine. It's under load, where the internal impedance becomes a factor to be calculated in the over all circuit, where it becomes a factor affecting the voltage drop on the cell based on current load. It's more a measure of the cells ability to hold it's voltage under increasing current load. 

What I would like to be able to reliably measure is the internal impedance of a cell when it's new and track that over the period of a few years to know when to retire the cell for higher current applications. For example: if I have an 18650 that it rated for 20A high current that I use in my vape gear I'd like to be able to check when it's a good time to replace it with a new one. At that point I can retire the cell from vaping, which can easily pull 10-15 Amps, to flashlight usage where I know it will more likely see 2-3Amp max loads. 

That's one of the features that lead me to purchase the BT-C3100. Definitely a let down. 

It is good for doing current rundown capacity tests but with only a 1Amp max discharge rate I don't think it's really putting much stress on the newer high current 18650 cells. I could definitely get better results with my RC hobby charger. Guess I'll end up building a good battery tray setup for that.


----------



## ChrisGarrett

I just got a new Opus BT-3400 v. 2.2 from rdana on Ebay and I've noticed that when I discharge my 4 Samsung 25Rs which are in good health and then go to charge them back up at 1A, the charger will reboot after about 10-15 minutes and default to a 500mA x 4 charging rate. 

I can charge them up at 700mA from empty and things charge smoothly. Also, once the cells get some energy and approach that 3.6v mark, the charger can handle all 4 of them at 1A and proceeds accordingly.

It seems that when they're empty, the 3A wall wart starts choking a bit and can't keep up.

NiMH batteries that are at 1.27v work fine on 1A for 4 of them. 2 26650s that are empty, charge up at 1.5A just fine, it's only when charging 4 empty 18650s (a set for my Supfire M6) that I run into a problem, at least until there CC/CV phase starts decreasing during the CC part.

I'll contact rdana and ask him if he's seen this problem before, but I don't have another 3A/4A wall wart to swap in to see if it's indeed the WW that is the problem.

Everything else works well.

Thanks, Chris


----------



## gyzmo2002

ChrisGarrett said:


> I just got a new Opus BT-3400 v. 2.2 from rdana on Ebay and I've noticed that when I discharge my 4 Samsung 25Rs which are in good health and then go to charge them back up at 1A, the charger will reboot after about 10-15 minutes and default to a 500mA x 4 charging rate.
> 
> I can charge them up at 700mA from empty and things charge smoothly. Also, once the cells get some energy and approach that 3.6v mark, the charger can handle all 4 of them at 1A and proceeds accordingly.
> 
> It seems that when they're empty, the 3A wall wart starts choking a bit and can't keep up.
> 
> NiMH batteries that are at 1.27v work fine on 1A for 4 of them. 2 26650s that are empty, charge up at 1.5A just fine, it's only when charging 4 empty 18650s (a set for my Supfire M6) that I run into a problem, at least until there CC/CV phase starts decreasing during the CC part.
> 
> I'll contact rdana and ask him if he's seen this problem before, but I don't have another 3A/4A wall wart to swap in to see if it's indeed the WW that is the problem.
> 
> Everything else works well.
> 
> Thanks, Chris



Mine worked well for about 3 months and the same problem as yours happened. I changed de power supply to a better one and no problem until that.

https://www.candlepowerforums.com/threads/408288


----------



## ChrisGarrett

gyzmo2002 said:


> Mine worked well for about 3 months and the same problem as yours happened. I changed de power supply to a better one and no problem until that.
> 
> https://www.candlepowerforums.com/threads/408288



Thanks and I remember that thread now.

What wall wart did you buy? Is the new one rated at 3A, or are there bigger ones out there?

I'm thinking that a 4A WW would work, but in your linked thread, it seems that they are hard to find.

At least it seems that my first guess is correct and that it's the power supply and not the charger.

Chris


----------



## gyzmo2002

Another 3A that I had but you can remove the cord. It is the same as a laptop power supply. It was probably connected to a hard disk before but not sure.

A 3A is supposed to be enough but the problem is probably the quality of the power supply that come with the charger is borderline and cannot give the 3A required under load.


----------



## ChrisGarrett

gyzmo2002 said:


> Another 3A that I had but you can remove the cord. It is the same as a laptop power supply. It was probably connected to a hard disk before but not sure.
> 
> A 3A is supposed to be enough but the problem is probably the quality of the power supply that come with the charger is borderline and cannot give the 3A required under load.



I emailed Robert (rdana) describing the problem and he replied that the wall wart is defective and he'll be sending a new one out to me ASAP.

So, for now, I'll hold off on buying the Dell DA-1, or something else and wait to see if this works.

Thanks for the help.

Chris


----------



## gyzmo2002

ChrisGarrett said:


> I emailed Robert (rdana) describing the problem and he replied that the wall wart is defective and he'll be sending a new one out to me ASAP.
> 
> So, for now, I'll hold off on buying the Dell DA-1, or something else and wait to see if this works.
> 
> Thanks for the help.
> 
> Chris



You are welcome.🙂


----------



## Sledgestone

What would be the best way to tell capacity on my cells with the 2.2v? 

Should I do a charge test which measures discharge capacity? Or simply discharge from what ever voltage the battery is at and then charge it to see charge capacity?

When I do a charge test on my ncr18650b 3400 mah they show a capacity just under 3600 mah. And when I simply charge them from empty I get around 3400-3480 mah.


----------



## light-wolff

Sledgestone said:


> When I do a charge test on my ncr18650b 3400 mah they show a capacity just under 3600 mah. And when I simply charge them from empty I get around 3400-3480 mah.


Both figures are too high to be true for an NCR18650B.
Li-Ion charge and discharge capacity is practically the same - if properly measured.


----------



## Sledgestone

I know. But I get virtually the same result every time..

Is anyone else getting these high figures?

Trying on a set of Tenergy 2600 mah now.


----------



## gyzmo2002

Sledgestone said:


> When I do a charge test on my ncr18650b 3400 mah they show a capacity just under 3600 mah. And when I simply charge them from empty I get around 3400-3480 mah.



The opus charges at 4.22v instead of 4.20v. Around 200mah more filled than 4.20v. That could explain why it gives a higher capacity than the cell rated. 

At this moment, I am trying the same test in my mc3000 at 4.22v. I did it yesterday but at 4.20v and the result was higher in my opus than in my mc3000.

Nb: in the opus, the charge test C>D>C is naming refresh C>D>C in the mc3000.

I have the opus v2.2


----------



## Sledgestone

According to my multimeter the batteries comes off the opus at 4.18. So that shouldn't be the case with mine?


----------



## gyzmo2002

Sledgestone said:


> According to my multimeter the batteries comes off the opus at 4.18. So that shouldn't be the case with mine?



Right after the end, 4.20v on the lcd and 4.22v on my Fluke for 2600mah 18650b rebranded cells. (Slot 1-2)

With another set but 3400mah "no brand" cell (ncr18650b protected), 4.20v on the lcd and 4.22v with my Fluke on slot 3 and 4.20V on slot 4.

Slot 4 has probably a more used cell.

These cells have about 10 cycles. I should do the same test with brand new cells. 



My mc3000 conttinue the test I started before...


----------



## gyzmo2002

Update:

2 18650 cells tested with my Opus BT-C3100 v2.2 in the charge test from 4.22v-2.80v-4.22v at 1A charge and discharge:

Cell1 capacity: 1984mah discharge
Cell2 capacity: 1909mah discharge

Same cell in my MC3000 from 4.22v-2.80v-4.22v, termination 0.05A:

Cell1 capacity: 1775mah discharge
Cell2 capacity: 1744mah discharge

Why the measured capacity in the Opus is higher than the capacity listed for the cell. I was always thinking that is because it charges to 4.22 instead of 4.20 but I was wrong according the results I just have with the mc3000.

When I received my ncr18650b, the capacity measured was always between 3550 and 3625mah. It is higher than the capacity listed for these cells.

The capacity measured with the mc3000 seems to be more accurate but I don't know why the opus give a higher capacity than the cell specs.


----------



## Sledgestone

I tried discharge and charge manually with both 2600 mah Tenergy and Keeppower 3400 mah (ncr18650b).

The results were much closer to specs this time.

2 x Tenergy 2600 showed around 2500 mah
Keeppower 3400 showed 3284 mah
Panasonic ncr18650b showed 3254 mah

Will try my other Panasonic ncr18650b again tomorrow and see if I still get around 3500-3600 mah. These are brand new btw, don't know if that makes any difference? Maybe they're on steroids


----------



## Sledgestone

gyzmo2002//

Have you tested the capacity of your ncr18650b with the mc3000?


----------



## gyzmo2002

Sledgestone said:


> gyzmo2002//
> 
> Have you tested the capacity of your ncr18650b with the mc3000?



No. The only time I test the capacity, it is when I receive new cells. I took a pictures of all batch I receive with the results and with the production date of the cells. I did some test since I have the mc3000 (5 days ago) but on cheap cells that I have. 

I have a brand new set of ncr18650b protected that was only use for the capacity test and stored since then at 3.70v. Production date sept first 2015. I could retest them in my mc3000 if you want with the same charge C>D>C test as I did with the Opus.

In the Opus at that time:
1-3610mah
2-3544mah
3-3585mah
4-3553mah

And in the mc3000:

I will give the charged capacity also with the mc3000.

To follow....test starts right now.


----------



## Sledgestone

That would be very helpful! Because those are pretty much the same numbers that I got. So that way I would have a better clue on my cells capacity.


----------



## gyzmo2002

Sledgestone said:


> That would be very helpful! Because those are pretty much the same numbers that I got. So that way I would have a better clue on my cells capacity.



But we won't know why the Opus give us values higher than the specs for the cell. Hope somebody will have the answer.


----------



## RI Chevy

The chargers are not perfect and not extremely accurate. Just use the cells and enjoy the light. Don't worry so much about the readings you are getting from the charger. I am sure the money you spent on the charger was put toward the "charging" aspect, and not that much money was placed on the gauges to give you extremely accurate readouts. Just check your voltage at the end of the charge with a good quality DMM. 
These types of chargers are gimmicky in my opinion.


----------



## gyzmo2002

RI Chevy said:


> The chargers are not perfect and not extremely accurate. Just use the cells and enjoy the light. Don't worry so much about the readings you are getting from the charger. I am sure the money you spent on the charger was put toward the "charging" aspect, and not that much money was placed on the gauges to give you extremely accurate readouts. Just check your voltage at the end of the charge with a good quality DMM.
> These types of chargers are gimmicky in my opinion.



I do it for learning. I don't like the auto mode on gadget. Trying to find answers is the best way to learn.


----------



## RI Chevy

OK. Just giving you a realistic answer to your question.


----------



## gyzmo2002

RI Chevy said:


> OK. Just giving you a realistic answer to your question.



No offense[emoji6]. I am trying to reproduce the same results with the mc3000. This charger is fully configurable in advanced mode. In that way, I learn parameters that charger uses to do that job. My opus do a good job but I want to figure how it does this job. 

In the case above, why it gives higher values than the cell spec. If I had the parameters the opus uses, it will be easy.
With the same parameters in the mc3000, If I have always higher capacity measures with the opus, it will be the accurancy of this charger. For now, I think it is. If yes, for about how much?


----------



## G. Scott H.

gyzmo, have you taken votage readings on any IMR cells fresh off this charger?


----------



## gyzmo2002

G. Scott H. said:


> gyzmo, have you taken votage readings on any IMR cells fresh off this charger?



No, I don't have IMR cells. I only use NCR for now. I have a set of LG MJ1, and LG HG2 if you want to.


----------



## gyzmo2002

gyzmo2002 said:


> No. The only time I test the capacity, it is when I receive new cells. I took a pictures of all batch I receive with the results and with the production date of the cells. I did some test since I have the mc3000 (5 days ago) but on cheap cells that I have.
> 
> I have a brand new set of ncr18650b protected that was only use for the capacity test and stored since then at 3.70v. Production date sept first 2015. I could retest them in my mc3000 if you want with the same charge C>D>C test as I did with the Opus.
> 
> In the Opus at that time:
> 1-3610mah
> 2-3544mah
> 3-3585mah
> 4-3553mah
> 
> And in the mc3000:
> 
> I will give the charged capacity also with the mc3000.
> 
> To follow....test starts right now.



For the follow up:

The specs of the cells tested:


http://s19.postimg.org/t4q259cqr/image.png





A refresh C>D>C: To be more accurate, I should have done this test from 4.20V to 2.50V with terminaison 65ma and 0.2C(670ma) accordind to the specs of the ncr18650b. 

I did it from 4.22v-2.80v with a terminaison 50ma at 1A charge-discharge.

I wanted to compare the results of the Opus 3100 that are too high than the rated capacity of the cell.

Charged capacity:
http://s11.postimg.org/ojjl9c9wz/image.png





Discharged capacity:
http://s18.postimg.org/wfzif8f89/image.jpg





Near the same results between the charged and the discharged capacity.

I am starting another test with 1 ncr18650b that I removed the PCB to discharged it to 2.50v and charged to 4.20v, terminaison 70ma(65ma), 0.2C(670ma). The max capacity rated for this cell is 3350mah at 25celsius. This cell has about 10 cycles. I try to be more accurate as possible. I should have removed the PCB from a cell I have tested above but I don't want to broke my set of 4. This test is for testing the accurancy of the mc3000.

The Opus gives a higher capacity as the cell listed(max3350mah)The Mc3000 seems to be more accurate. The differences between the Opus and the Mc3000 is about +-400mah/cell.

If you have any questions, feel free to ask. I will do my best to answer you.


----------



## gyzmo2002

For the other test above with mc3000 for 1 ncr18650b from 4.20>2.50>4.20v with parameter listed above (datasheet)

Charged capacity: 3224mah






Discharged capacity: 3252mah

http://s19.postimg.org/5079n551f/image.jpg







With the max capacity rated for this cell (3350mah), the mc3000 is really close and probably target. The cell tested was about 10 cycle of use. 

Now, I will do the test in the Opus. I will do it at 700ma in the charge test C>D>C. But don't forget, the Opus charge to 4.22 and discharge to 2.80 and we cannot change it.


----------



## gyzmo2002

Results for the Opus:

http://s19.postimg.org/63rdz3poj/image.jpg





Discharged capacity measured: 3502mah instead of 3252mah with the mc3000. The capacity measured with the Opus is too high than the cell specs.


----------



## ChrisGarrett

gyzmo2002 said:


> Results for the Opus:
> 
> http://s19.postimg.org/63rdz3poj/image.jpg
> 
> Discharged capacity measured: 3502mah instead of 3252mah with the mc3000. The capacity measured with the Opus is too high than the cell specs.



I haven't toyed with my 3400 v. 2.2 for very long, but it's seemingly measuring discharge capacity in a reasonable manner--nothing abnormally high, as you're describing.

Last night, I did two 3 year old Sanyo UR14500Ps and got ~730mAh at a 500mA charge and discharge rate. I also did a two year old Redilast 17670 and got about 18xx mAh, which is reasonable, since I didn't charge it up to 4.30v. Charge/discharge on that one was 700mA, so about .33C.

Maybe something's wrong with your Opus?

I could go on, but nothing has struck as being out of the ordinary, unlike my Xtar VC4, which has sometimes missed termination and pumped in a lot more than normal (but remember the Maha C9000 on Break In) with NiMH batteries.

Chris


----------



## gyzmo2002

ChrisGarrett said:


> I haven't toyed with my 3400 v. 2.2 for very long, but it's seemingly measuring discharge capacity in a reasonable manner--nothing abnormally high, as you're describing.
> 
> Last night, I did two 3 year old Sanyo UR14500Ps and got ~730mAh at a 500mA charge and discharge rate. I also did a two year old Redilast 17670 and got about 18xx mAh, which is reasonable, since I didn't charge it up to 4.30v. Charge/discharge on that one was 700mA, so about .33C.
> 
> Maybe something's wrong with your Opus?
> 
> I could go on, but nothing has struck as being out of the ordinary, unlike my Xtar VC4, which has sometimes missed termination and pumped in a lot more than normal (but remember the Maha C9000 on Break In) with NiMH batteries.
> 
> Chris



I have the same results as Sledgestone above. That'a why I did the test. Since I had the mc3000 that could be configurated correctly, I have something to compare. We cannot change parameters in the Opus, just charge-discharge rate. It charges to 4.22V (DMM) and discharge to 2.80v. To be accurate, you need to do the test with the ncr18650B from 4.20-2.50v with the specs written above.

All results I have seen for the ncr18650b with the opus, are always higher than the max capacity rating for the cell. The max capacity for this cell at 25C is 3350mah.


----------



## gyzmo2002

If the Opus was configurable and could decharge to 2.50v, what will be the result?

3800-3900mah? When I received my new battery, all my test are between 3500-3625mah. After that I left a comment to the seller and the comments left from the others are always good capacity cells, original with some results. Some post pictures to prove it and from the ones with the opus, they are always in the same range as mine. For myself, the results are clear.


----------



## RI Chevy

They could give the ULTRAFIRE 4000 mAh cells a run for the money.


----------



## gyzmo2002

RI Chevy said:


> They could give the ULTRAFIRE 4000 mAh cells a run for the money.



I will never try an Ultrabullshit in my MC3000 lol[emoji13]


----------



## gyzmo2002

RI Chevy said:


> The chargers are not perfect and not extremely accurate. Just use the cells and enjoy the light. Don't worry so much about the readings you are getting from the charger. I am sure the money you spent on the charger was put toward the "charging" aspect, and not that much money was placed on the gauges to give you extremely accurate readouts. Just check your voltage at the end of the charge with a good quality DMM.
> These types of chargers are gimmicky in my opinion.



You were right but I wanted to know more and proof it with this test. I always have higner results with the Opus but the capacity test was done only to know if the cells I have bought, had the capacity listed. With a higher one than listed, it was ok for me. If they were under, I had returned the cells to the sellers. It was funny to measured capacity with the ultrafire 4200mah that I had received with my first cheap china brand headlight (5000lumens lol). I knew nothing about cells 5 months ago. I began with a D4 but wanted to measured capacity. I bought the Opus and I like it very much. With the MC3000, you learn a lot. It is easy to play with. I will keep my Opus as my second charger. 

It would be great to do the same test as I did with the Likotta or another good charger to compare results with the Opus. The MC 3000 is fully configurable so, more chance to be on target with the cells spec. 

If someone could do the C>D>C with another brand of charger with ncr18650b, it will be nice to post them to compare.


----------



## gyzmo2002

Sledgestone said:


> What would be the best way to tell capacity on my cells with the 2.2v?
> 
> Should I do a charge test which measures discharge capacity? Or simply discharge from what ever voltage the battery is at and then charge it to see charge capacity?
> 
> When I do a charge test on my ncr18650b 3400 mah they show a capacity just under 3600 mah. And when I simply charge them from empty I get around 3400-3480 mah.



If you want me to do the test for a charge capacity C> alone and a discharge capacity D> alone instead the C>D>C above, just tell me. I have tried it with the Opus before and the discharge capacity was different than the charge capacity and lower than the disharged capacity of the C>D>C(named charge test in the Opus)

I do not remember if it was the charge or discharge capacity that was the highest but remember that they were higher than the cell's rating.


----------



## gyzmo2002

Some other tests with the Opus with Evva 3500, LG HG2 3000, Eneloop Pro AAA, Eneloop AAA, Eneloop Pro AA, LG MJ1 3500.
All these cells were new at that time.

[img=http://s19.postimg.org/90snnzglb/image.jpg]

[img=http://s19.postimg.org/9b067bv7j/image.jpg]

[img=http://s19.postimg.org/gcy3tiytb/image.jpg]

[img=http://s19.postimg.org/8mrbodwhr/image.jpg]

[img=http://s19.postimg.org/uprjruitb/image.jpg]

[img=http://s19.postimg.org/ppu3jwd6n/image.jpg]

If you want to compare with yours. Charge test C>D>C at 1A for the 18650, probably 800ma for Enelopp Pro AA and prob. 400ma for the AAA.


----------



## G. Scott H.

gyzmo2002 said:


> No, I don't have IMR cells. I only use NCR for now. I have a set of LG MJ1, and LG HG2 if you want to.



Do INR cells (MJ1, etc.) have a similar internal resistance to IMR? If so, then yes, I'd be interested. I've heard that some chargers can overcharge IMR. I haven't experienced this myself, since I've only used Nitecore "i" and "d" series chargers, but if your Opus is charging ICRs up to 4.22V, I was wondering if it might overcharge an IMR. Thanks.


----------



## gyzmo2002

I'm not familiar with this type of cell. I don't want to give you a wrong answer. You can take a look at this link. You will probably find the answer because he has already tested IMR in the Opus. 

http://lygte-info.dk/review/Review Charger Opus BT-C3100 Software V2 UK.html


----------



## gyzmo2002

Delete


----------



## ChrisGarrett

G. Scott H. said:


> Do INR cells (MJ1, etc.) have a similar internal resistance to IMR? If so, then yes, I'd be interested. I've heard that some chargers can overcharge IMR. I haven't experienced this myself, since I've only used Nitecore "i" and "d" series chargers, but if your Opus is charging ICRs up to 4.22V, I was wondering if it might overcharge an IMR. Thanks.



4.22v is in spec for lithium ion ICR/IMR/INR type chemistries, it's actually 4.20v (+/- .05v,) so even 4.25 is OK. There were some early reports of the NiteCore terminating above 4.25v and that wasn't good, but my i4 v.2 actually charges to 4.20v with most every healthy cell, unlike some of my Xtar chargers which hit 4.18v-4.19v as a rule (actually better for cells to undercharge them vs. overcharging them.)

I don't know of any reason why lower resistance cells or IMRs (many modern hybrids have low I.R.s out of the box,) would have a problem.

If you have a decent DMM, you can check your cells hot off the charger and see. I still do this 4 years into my li-ion journey.

I just want to know, like Moulder.

Chris


----------



## lemo

Hi. Sorry if this is a daft question.. Why would you want to manually change the charge current? Is it just about slow vs fast charge?

Thanks.


----------



## ven

lemo said:


> Hi. Sorry if this is a daft question.. Why would you want to manually change the charge current? Is it just about slow vs fast charge?
> 
> Thanks.




Various cells require various rates, a 14500 would require a lower rate than a 26650 as one example(0.25a/0.5a and 2a as one).

Depending on the 18650, there can be variations, charging a 2600mah ICR to a 3500mah cell has a different rating(C).

IMR and INR cells, can take higher charge and discharge rates.


----------



## lemo

Thx ven. Small world, I used to live in Chorlton and want to move back there.

I have been leaving my opus on default 500mA. Is this ok for AA, AAA, 14500, 18650 or do I need to start learning about charge rates for different cells?


----------



## ven

lemo said:


> Thx ven. Small world, I used to live in Chorlton and want to move back there.
> 
> I have been leaving my opus on default 500mA. Is this ok for AA, AAA, 14500, 18650 or do I need to start learning about charge rates for different cells?



It is!
I use 500ma for AAA, 1a for AA, 14500 varies from 0.25 to 0.5a. 18650 varies from 1a(most used) to 1.5a for my IMR/INR cells.

Yes basically, you can charge the AA and 18650 at 1a rate which will be considerably quicker if time is an issue. No detrimental effect, or to me unnoticeable from the old days of lower rate chargers.


----------



## lemo

Good info. Thanks again bud.


----------



## ven

Welcome, it used to kill me waiting on the i4 with 4 bays going, iirc about 0.35a rate and felt the best part of a day with 3400mah cells :laughing:


----------



## markr6

ven said:


> Welcome, it used to kill me waiting on the i4 with 4 bays going, iirc about 0.35a rate and felt the best part of a day with 3400mah cells :laughing:



Wow, .35a is like a trickle charge on 18650s. Especially the new ones.


----------



## ven

Yes iirc as been a while..........ok years! its 0.75a for 2 cells on the correct 2 bays, then 0.375a on all 4..............good old days.

Having spare cells is key anyway, but still its no good waiting 5+hrs for a charge.........


----------



## xzel87

just want to chip in, my opus shows my 2 NCR 18650B discharge capacity at 3600+ mah as well...doesn't really matter, still good cells and capacity is at least 3400 mah. I tested a Blue Ultrafire 3000mah cell before and discharge at 1A only have me 300+ mah.


----------



## novasquid

regarding using the charger in a car, i guess i found the answer to my own question here.


----------



## TinderBox (UK)

Are the BT-C3100 version`s without the OPUS logo on the front, fake or clones?

John.


----------



## HKJ

TinderBox (UK) said:


> Are the BT-C3100 version`s without the OPUS logo on the front, fake or clones?



Opus is a OEM supplier, this means they sells the charger with different names on. You can also see that in my reviews of their chargers: Many of them is without names, even the box is without brand name.
I.e. a missing Opus logo do not suggest a fake or clone, you will have to look for other details to see that.


----------



## TinderBox (UK)

Thanks Henrik, It good to know.

Is the full manual only 4 pages as that is all i can find.

My BT-C3100 v2.2 i just ordered just shipped i paid £21 

John.


----------



## Joe Kidd

Yep, it's just four pages. It's more informative that the example I found online.
I could email a pdf of pages 2 & 3 if you like. The other two pages have little info.


----------



## novasquid

my opus' fan started screeching a day or two after i got it. i unscrewed the backside to get to the fan, but don't see a way to remove the fan. do i also need to unscrew the pcb in order to remove the fan?


----------



## TinderBox (UK)

Just received my FLOUREON branded BT-C3100 v2.2 with UK power adaptor from ebay for £21 delivered.

The slots are a bit stiff, also it does not give any indication that a process is complete, I did a discharge on an nimh aa and the only way i knew it was complete was the discharging current had dropped to 0ma, is this the same for charge.

changes between v2.1 and v2.2

1. press “display“button for 5s can turn on back light permanently. Press another 5s to resume normal 30s time out off function.
2. Refresh mode show “discharge” capacity instead of “charge” capacity.

John.


----------



## gyzmo2002

TinderBox (UK) said:


> Just received my FLOUREON branded BT-C3100 v2.2 with UK power adaptor from ebay for £21 delivered.
> 
> The slots are a bit stiff, also it does not give any indication that a process is complete, I did a discharge on an nimh aa and the only way i knew it was complete was the discharging current had dropped to 0ma, is this the same for charge.
> 
> John.



After charge completed, you will see FULL. Samething with a charge test (C>D>C) ou disharge test D>C. You will see FULL after the last charge.


----------



## ven

Work a little bit of nyogel in the spring/slide John, frees the slots up a bit.


----------



## TinderBox (UK)

Thanks guy`s

I was comparing a downloaded manual, to the one i received with my v2.2 charge, the manual i downloaded says it trickles after discharger, and mine says it does not trickle after discharge this must be one of the changes.

John.


----------



## gyzmo2002

TinderBox (UK) said:


> Thanks guy`s
> 
> I was comparing a downloaded manual, to the one i received with my v2.2 charge, the manual i downloaded says it trickles after discharger, and mine says it does not trickle after discharge this must be one of the changes.
> 
> John.



My post above is for Li-ion. I am trying a charge with nimh to see if it is the same.


----------



## gyzmo2002

It is the same with nimh. FULL on the display after the charge but with a trickle charge of 30ma.


----------



## TinderBox (UK)

Has anybody got version v2.2 of the manual in pdf that i can download.

Also how do i do a standard capacity check on say a standard Eneloop AA

Thanks

John.


----------



## gyzmo2002

TinderBox (UK) said:


> Has anybody got version v2.2 of the manual in pdf that i can download.
> 
> Also how do i do a standard capacity check on say a standard Eneloop AA
> 
> Thanks
> 
> John.



A charge test. The charger will charge , discharge and charge again. It will give you the discharged capacity and keep it to the end of the last charge.


----------



## TinderBox (UK)

Yeah, but a standard discharge rate is 0.2C, how do i set the charge to say 1000ma and discharge rate 400ma

John.



gyzmo2002 said:


> A charge test. The charger will charge , discharge and charge again. It will give you the discharged capacity and keep it to the end of the last charge.


----------



## gyzmo2002

TinderBox (UK) said:


> Yeah, but a standard discharge rate is 0.2C, how do i set the charge to say 1000ma and discharge rate 400ma
> 
> John.



When inserting the battery, you will see 500ma flashing. Click CURRENT and you will change it. If it doesn't flash, that's mean you take too much time to change it. 

You cannot have a different charge and discharge. They are at the same rate.


----------



## TinderBox (UK)

That`s a shame and a waste of time on the charge side, on my LaCrosse BC-900 it charges at double the discharge rate, so discharge 500ma gets charge 1000ma

Thanks

John.


----------



## gyzmo2002

TinderBox (UK) said:


> That`s a shame and a waste of time on the charge side, on my LaCrosse BC-900 it charges at double the discharge rate, so discharge 500ma gets charge 1000ma
> 
> Thanks
> 
> John.



With the MC3000, you can do all the settings you want. I no longer use my opus or my D4. In the near future, I think that you're going to have one instead to have 2-3 different charger. [emoji6]


----------



## TinderBox (UK)

The MC3000 is way outside of my price range, I will just have to learn to wait till the C3100 is finishes in it own slow time.

John.


----------



## ChrisGarrett

TinderBox (UK) said:


> The MC3000 is way outside of my price range, I will just have to learn to wait till the C3100 is finishes in it own slow time.
> 
> John.



'Slow' is relative.

If your life revolves around batteries being charged up at 2A, instead of 1A, then you're doing things wrong...ie: not having a spare set.

There are great reasons to buy the MC3Zillion, but for me, a faster charging rate isn't one of them.

I think that I used the 2A rate only once in 4+ years on my Maha C9000 and I've fiddled with the 2A rate on my BT-3400 once, on one of my Efest IMR 26650s, just to say I did it and to feel the rush.

I'm still not down off the mountain.

Chris


----------



## TinderBox (UK)

My fan sounds like a vhs video tape rewinding at full speed, i keep expecting the clunk of the tape stopping.

John.


----------



## Joe Kidd

Fans must vary. Mine is just a whisper. I can't hear it 30ft away.


----------



## ven

TinderBox (UK) said:


> My fan sounds like a vhs video tape rewinding at full speed, i keep expecting the clunk of the tape stopping.
> 
> John.




That quiet ! :laughing:

If i had a pound for every "whats that noise?" from visitors i would have £128 of them by now........


----------



## TinderBox (UK)

Replacement fans are cheap enough.

http://www.gearbest.com/diy-parts-a...currency=GBP&gclid=CNrNqt3NqssCFSbkwgodQy8G-g

John.


----------



## ven

TinderBox (UK) said:


> Replacement fans are cheap enough.
> 
> http://www.gearbest.com/diy-parts-a...currency=GBP&gclid=CNrNqt3NqssCFSbkwgodQy8G-g
> 
> John.




Nice find John!! ordered even though i am used to the noise :laughing: Kind of a personality and usually causes a raised eyebrow or two! 

Will forget all about it and in a few weeks i will get a small package and think " what the........ is this?"


----------



## novasquid

is there a trick to removing the fan to put in a replacement?


----------



## TinderBox (UK)

I just ordered one myself at this price it`s worth having a spare, just store it in the charger box.

John.



ven said:


> Nice find John!! ordered even though i am used to the noise :laughing: Kind of a personality and usually causes a raised eyebrow or two!
> 
> Will forget all about it and in a few weeks i will get a small package and think " what the........ is this?"


----------



## novasquid

novasquid said:


> is there a trick to removing the fan to put in a replacement?


since no one else replied I went digging through the net and found a helpful video. in case anyone else is in my shoe wondering how the fan is removed, fast fwd to 3 minutes: https://www.youtube.com/embed/tuBtXKm7eaA


----------



## ven

Nice find novasquid!


----------



## kosPap

some long term use observations.
1. the spring are too weak for RCR123 batteries
2. The fan induces intereference to my radio receiver


----------



## ChrisGarrett

kosPap said:


> some long term use observations.
> 1. the spring are too weak for RCR123 batteries
> 2. The fan induces intereference to my radio receiver



I was playing with mine last night and you're right about 16340s. Just barely enough tension to make an acceptable contact and I've had slot 4 just stop charging. I try and let the sliders snap into place against the rear of the cells, but they did botch that aspect, IMO.

I listen to a TecSun PL390 a lot out on my patio and lights, power banks and chargers do create RFI and I can hear it through the speakers at times.

Chris


----------



## gunga

Is there a recommended vendor for this charger?


----------



## novasquid

may be hit or miss, but gearbest has it for $33us and it took 2 weeks to ship to the us.


----------



## gunga

Sigh. Yeah. Trying to avoid Gearbest. I've actually had decent success ordering there but it is a bit of a lottery at times.


----------



## ChrisGarrett

gunga said:


> Is there a recommended vendor for this charger?



Robert Dana on Ebay (rdana) sells his Opus BT-3400 v. 2.2, which is the 3100 v. 2.2 labeled for his customers.

<$50 gets you the 3400 and a 12v car adapter.

Great service and I bought my Maha C9000, LaCrosse BC-700 and assorted adapters and NiMH batteries from him over the past 4+ years.

He's in Sacramento, CA and ships to Canada.

http://www.ebay.com/itm/BT-C3400-Ba...442603?hash=item4d305647ab:g:ewkAAOSwqu9VIej8

Chris


----------



## TinderBox (UK)

Hi Chris i thought the Opus BT-3400 was v2.1 only, is there an v2.2 version now?

John.


----------



## ChrisGarrett

TinderBox (UK) said:


> Hi Chris i thought the Opus BT-3400 was v2.1 only, is there an v2.2 version now?
> 
> John.



Yep, mine's a v. 2.2 and I can keep the backlit display on or toggle it to go off after X amount of seconds.

I also drilled a hole in the bottom of mine, so I can access the slider switch to toggle between 3.20v, 4.20v and 4.35v charging, so it's similar to my Xtar VP2 in that regard. 

I think that the fan has been tweaked a bit, but I'm not sure on that.

Mine is whisper quiet for now. It's not a perfect charger and I think that mine reads perhaps 5% high, as I said above and perhaps it's not as great a charger on NiMH, as my C9000 is, but it's pretty nifty.

I got the 12v car adapter with mine, which bumps the price up to just below $50 shipped.

Chris


----------



## markr6

Chris, what is it reading high? mAh? Voltage while charging, or everything?

I have the 2.2 and the fan is very quiet, I would say on par with a cheap-mid price range laptop.


----------



## ChrisGarrett

markr6 said:


> Chris, what is it reading high? mAh? Voltage while charging, or everything?
> 
> I have the 2.2 and the fan is very quiet, I would say on par with a cheap-mid price range laptop.



Well, this is just my observation, but when I first got it, I discharged my older cells, like my LG D1s (3000mAh 4.35v) and my LG E1s (3200mAh 4.35v) on it, after charging them up on my VP2 (before I drilled the hole) and at a 1A discharge, I was right on the money at 3000mAh and 3200mAh. These cells are a couple of years old and I guess I expected there to be some capacity loss and not being practically 'dead on.'

The other night, I charged/discharged four Eneloop green AAAs that are at least four years old and got: 841mAh, 828mAh, 819mAh and 848mAh on the Opus, at around 300mA discharge and then repeated the process on my Maha getting 765mAh, 770mAh, 749mAh and 768mAh.

On the Maha, IR is reading about 1.59v for the 4, so they've seen some action.

Just little things like that. I know that slot 1 on the Maha does seem to undercharge the battery a bit, or at least consistently displays a lower capacity, but not always.

Little quirks like that, but I'm no EE, so maybe I'm wrong?

Also, I'm noticing that even with fresh li-ions, when I remove the cells and measure, they're 4.17v-4.18v, so much like some of my Xtar chargers, they're 'undercharged' a bit, which is a good thing, ultimately, like Martha would say

Chris


----------



## TinderBox (UK)

Has anybody bought the D cell adaptor, I saw one on Amazon are there different quality version, has anybody tried them.

http://www.amazon.com/dp/B00CR6TAJ2/?tag=cpf0b6-20

John.


----------



## ChrisGarrett

TinderBox (UK) said:


> Has anybody bought the D cell adaptor, I saw one on Amazon are there different quality version, has anybody tried them.
> 
> http://www.amazon.com/dp/B00CR6TAJ2/?tag=cpf0b6-20
> 
> John.



They look similar to rdana's adapters here:

http://www.ebay.com/itm/2-Pack-C-D-...053017?hash=item4ac95f6899:g:UWcAAOxyW7tRgxRS

For that price, I may just pick up two and buy some Tenergy Premium D batteries and try it out. There can be a fitment issue with some Maha C9000s, but it looks like they're good on the 3100/3400s.

<$7, it's not much of a gamble for me.

Chris

ETA: I just bought two of them, so we'll see. Now I need some batteries, lol.


----------



## TinderBox (UK)

I found them here for the UK buyers, 2 pack for £3.79/$5.41

http://www.ebay.co.uk/itm/2-Pack-D-...rge-Test-D-Cells-in-BT-C2000-Y8-/391186860522

John.


----------



## ChrisGarrett

TinderBox (UK) said:


> I found them here for the UK buyers, 2 pack for £3.79/$5.41
> 
> http://www.ebay.co.uk/itm/2-Pack-D-...rge-Test-D-Cells-in-BT-C2000-Y8-/391186860522
> 
> John.



You beat me you *******!

Lock your doors tonight.

For less than a six pack of cheap beer, they're worth it to me.

I have an old 80s era GE Ni-Cad moron charger and wasn't looking forward to using it.

Good score.

Chris


----------



## ven

I have a couple John that i dont use anymore(not got my tk50 now), pm me your add and will post em to you


----------



## TinderBox (UK)

Hi.

Thanks Ven but i ordered a couple yesterday, you generosity is much appreciated. :bow:

John.



ven said:


> I have a couple John that i dont use anymore(not got my tk50 now), pm me your add and will post em to you


----------



## ven

Ok John

They do the job fine, can feel a tad loose side to side ,but work so no real issue


----------



## N7JGN

Does this charger allow you to get capacity readout immediately after inserting battery? Or do you have to do a full discharge and recharge. I want a charger that will read capacity right off the bat in mAh.. So if I insert a brand new 2500 mAh it will tell me what it is.. If not this charger, what charger/analyzer will? Newbie here..
Thanks in advance..
Doug


----------



## HKJ

N7JGN said:


> Does this charger allow you to get capacity readout immediately after inserting battery?



That is not possible on any charger, the only time you can do that is for batteries that has a build in chip to check their charge condition.


----------



## tripplec

N7JGN said:


> Does this charger allow you to get capacity readout immediately after inserting battery? Or do you have to do a full discharge and recharge. I want a charger that will read capacity right off the bat in mAh.. So if I insert a brand new 2500 mAh it will tell me what it is.. If not this charger, what charger/analyzer will? Newbie here..
> Thanks in advance..
> Doug



My Soshine H4 does for LiIon batteries and somewhat for NiMh their current voltage withing a few seconds after insertion. It also adjust as it charges. I like that giving me an idea how low I ran the batteries. There is virtually no discussion on this charger but I bought it anyway and happy I did. I charge my 18650's at 1000mA and each slot can be configured for a different charging current.


----------



## TinderBox (UK)

I have the H4 as well but it`s only a charger not a battery tester, Does it take charging inefficiency into account as it`s charging capacity results seem very close to my discharge capacity tests of the same battery on my battery charger/testers.

John.



tripplec said:


> My Soshine H4 does for LiIon batteries and somewhat for NiMh their current voltage withing a few seconds after insertion. It also adjust as it charges. I like that giving me an idea how low I ran the batteries. There is virtually no discussion on this charger but I bought it anyway and happy I did. I charge my 18650's at 1000mA and each slot can be configured for a different charging current.


----------



## tripplec

I know its not a tester. But its good to hear someone else here actually using one. The charging info is useful in my opinion and works for me. I have an IQ-328 and a Nitecore I4 but the IQ-328 is the worst of them all. I use the IQ-328 to analyze my Eneloops if I am curious about capacity but don't use it for for charging anymore.


----------



## TinderBox (UK)

The H4 is an great, standard nimh and li-ion charger, and i was amazed on how light it is, I just wish it was 5volt micro-usb powered.

John.


----------



## TinderBox (UK)

Hi.

What process does TEST (present capacity test according to the manual) as it seems to discharge and then charge and then give the capacity, should it not charger then discharge and do a full charge and then give the capacity.

John.


----------



## HKJ

TinderBox (UK) said:


> Hi.
> 
> What process does TEST (present capacity test according to the manual) as it seems to discharge and then charge and then give the capacity, should it not charger then discharge and do a full charge and then give the capacity.
> 
> John.




Here is a chart from the review:






It includes charge, discharge and charge.


----------



## TinderBox (UK)

Thanks Henrik, I was getting some low capacity results on a set of battery`s i will run the test again.

John.



HKJ said:


> Here is a chart from the review:
> 
> 
> 
> 
> 
> It includes charge, discharge and charge.


----------



## novasquid

ChrisGarrett said:


> I just got a new Opus BT-3400 v. 2.2 from rdana on Ebay and I've noticed that when I discharge my 4 Samsung 25Rs which are in good health and then go to charge them back up at 1A, the charger will reboot after about 10-15 minutes and default to a 500mA x 4 charging rate.





gyzmo2002 said:


> A 3A is supposed to be enough but the problem is probably the quality of the power supply that come with the charger is borderline and cannot give the 3A required under load.





ChrisGarrett said:


> I emailed Robert (rdana) describing the problem and he replied that the wall wart is defective and he'll be sending a new one out to me ASAP.
> So, for now, I'll hold off on buying the Dell DA-1, or something else and wait to see if this works.
> 
> Thanks for the help.
> 
> Chris



i'm using a laptop power brick that's rated at 12v 3a in place of the opus power supply, and had the same thing happen to me when i tried charging 4 18650s at 1a. a few minutes into the charge and the charger rebooted. are you guys still having the same issue or did the change in power brick help resolve it?


----------



## markr6

I've been running my v2.2 hard for months now. No issues at all; 18650, AA, sometimes a mix of both. Hopefully I won't need to switch to another power supply.


----------



## ven

Me too, regular have bays 1+4 at 1.5a or all 4 on 1a.................several times a day..............every day. Been faultless....................famous last words!


----------



## novasquid

i have 4 18650s i pulled from a laptop battery that are waiting to be recharged, so i'll try it again but with the original opus power cord this time and see how it goes.


----------



## novasquid

I haven't had this problem reappear using the oem opus charger so I guess it was my laptop charger that wasn't up to the task.


----------



## novasquid

I was discharging some new eneloop pros and mistakenly shut off power to the opus, but noticed the display showed it was still being powered. is that from the batteries being discharged?


----------



## HKJ

novasquid said:


> I was discharging some new eneloop pros and mistakenly shut off power to the opus, but noticed the display showed it was still being powered. is that from the batteries being discharged?



I have not tested that, but it is most likely the capacitors in the charger and power supply that maintains the power for a few seconds. I would expect the battery voltage to be too low to power the charger.


----------



## tripplec

Quick question as there are various Firmware for this charger as well as some other.

Is the Firmware user upgradable? Or are you stuck with the once shipped to you. I am not sure where its marked/indicated.


----------



## HKJ

tripplec said:


> Quick question as there are various Firmware for this charger as well as some other.
> 
> Is the Firmware user upgradable? Or are you stuck with the once shipped to you. I am not sure where its marked/indicated.



It is not user upgradable, you are stuck with the one you get. It is show on the display during power on.
This firmware "fun" was some time ago, I would expect all chargers in shops to be the new version now.


----------



## TinderBox (UK)

As far as i know you are stuck with the firmware you get, it may be possible to upgrade but i guess you would have to buy some expensive equipment.

It would be nice if we could. :mecry:I hope i am proven to be wrong.

John.



tripplec said:


> Quick question as there are various Firmware for this charger as well as some other.
> 
> Is the Firmware user upgradable? Or are you stuck with the once shipped to you. I am not sure where its marked/indicated.


----------



## tripplec

TinderBox (UK) said:


> As far as i know you are stuck with the firmware you get, it may be possible to upgrade but i guess you would have to buy some expensive equipment.
> 
> It would be nice if we could. :mecry:I hope i am proven to be wrong.
> 
> John.



Precisely what I was hoping for in a higher end unit. If there are bugs (and there are in the few currently reviewed). Fixes for this and the Sky charger a few threads away are of no help to current owners. Some online sellers may not ship the latest expected version either. Then the smart people would have to what a long time until its verified as fixed and highly recommended. No sales until then.

Hmmm

Thanks TinderBox, I just thought I'd ask.


----------



## TinderBox (UK)

I have the Opus BT-C3100 v2.2 myself and just bought the SkyRC MC3000 a few days ago and the BT-C3100 has not been used since.

The SkyRC MC3000 is the only charger i know that you can update the firmware at the moment, and it needs it as it has quite a few bugs as it`s a work in progress and is for the more advanced user even though it has an dumb mode, The BT-C3100 is the best charger for the price and is still more complicated than the average charger but is great value for money and is my best buy.

John.



tripplec said:


> Precisely what I was hoping for in a higher end unit. If there are bugs (and there are in the few currently reviewed). Fixes for this and the Sky charger a few threads away are of no help to current owners. Some online sellers may not ship the latest expected version either. Then the smart people would have to what a long time until its verified as fixed and highly recommended. No sales until then.
> 
> Hmmm
> 
> Thanks TinderBox, I just thought I'd ask.


----------



## novasquid

i have the v2.2 of this charger and i'm having the worst luck with it. very first one was sent back because of the grinding fan, but now i've gone through 3 replacements because they ALL terminate charging early on AA ni-mh (eneloop pros and ikea laddas). they all terminate at around 1.41volts, which comes out to about 2100mah of capacity versus the expected 2400+. ironically, the one with the bad fan was the only one that terminated properly, and now i wish i had that one back. 

i can't believe all 20 of my AA batteries are defective, so it must be the charger, right? maybe they did a firmware change on the v2.2 recently?


----------



## TinderBox (UK)

what charge rate are you using?

also how are you determining the capacity, with an 0.2c discharge?


----------



## mcnair55

Mine is working ok and much quicker than my Nitecore.


----------



## novasquid

TinderBox (UK) said:


> what charge rate are you using?
> 
> also how are you determining the capacity, with an 0.2c discharge?



200ma charge rate, and 200ma discharge rate. i've done it both manually (charge, then discharge) and charge-test method. also tried 500ma charge and 200ma discharge, with same results. i haven't tried higher charge rates like 1A, but if it can't do 200 and 500ma properly, then it's still broken even if 1A works fine.

one real life test i did was take a known fully charged set of AAs, put them in my TN4A and burn it on high until they're fully drained. that's 2hours, 36 minutes of time and as expected. then charge the batteries at 200ma until charger says "full" then do the same burn on the TN4A again on high, and this time only get 1:30 to 2:00 hours of time.


----------



## HKJ

novasquid said:


> i haven't tried higher charge rates like 1A, but if it can't do 200 and 500ma properly, then it's still broken even if 1A works fine.



No, anything below 0.3C is a bonus, 0.5C is safer. With 2400mAh batteries that means 800mA is absolute minimum and 1200mA is safer.

Usual the problem will be missed termination with low charge current, i.e. I am not sure a higher current will solve your problem.

You can read a bit about charging here: http://lygte-info.dk/info/batteryChargingNiMH UK.html


----------



## novasquid

HKJ said:


> No, anything below 0.3C is a bonus, 0.5C is safer. With 2400mAh batteries that means 800mA is absolute minimum and 1200mA is safer.
> 
> Usual the problem will be missed termination with low charge current, i.e. I am not sure a higher current will solve your problem.
> 
> You can read a bit about charging here: http://lygte-info.dk/info/batteryChargingNiMH UK.html




thanks for the link. i'll give 1A charge a try, but you think all 3 of the chargers are defective?


----------



## HKJ

novasquid said:


> thanks for the link. i'll give 1A charge a try, but you think all 3 of the chargers are defective?



No, it is unlikely. 
Opus is using some very smart algorithms to terminate correctly, maybe they have tweaked them a bit too much in the current version of the charger (The software number may not always be updated when the software is updated).


----------



## novasquid

HKJ said:


> No, it is unlikely.
> Opus is using some very smart algorithms to terminate correctly, maybe they have tweaked them a bit too much in the current version of the charger (The software number may not always be updated when the software is updated).



thanks for replying, i was just wondering what you meant when you wrote earlier, "_I am not sure a higher current will solve your problem."_ because it sounds like you were saying all 3 chargers were defective. _
_


----------



## ven

I have never tried my AA loops on anything bellow 1a, imho 0.5a is even too low, i am sure 1a will give you a better termination voltage


----------



## mcnair55

ven said:


> I have never tried my AA loops on anything bellow 1a, imho 0.5a is even too low, i am sure 1a will give you a better termination voltage



So using the default setting on loops is no good Ven ?


----------



## markr6

1A and Eneloops goes together like PB&J. Always works, not too hard on the cell, fast enough for me. I've found 500mA to be the worst on other chargers...didn't know when to quit. So I never tried it on the Opus.


----------



## novasquid

so looks like my 3 chargers are working fine then. anybody want an Opus v2.2 for cheap?


----------



## mcnair55

markr6 said:


> 1A and Eneloops goes together like PB&J. Always works, not too hard on the cell, fast enough for me. I've found 500mA to be the worst on other chargers...didn't know when to quit. So I never tried it on the Opus.



Note taken AA Eneloops in future at 1A charge...What about my AAA ?


----------



## markr6

mcnair55 said:


> Note taken AA Eneloops in future at 1A charge...What about my AAA ?



I don't use AAA much at all, but when I do I charge at 500mA.


----------



## ven

Yes as above mr mcnair, 1a for AA and 0.5 for AAA loops, thats what i use
In a nut shell, these are the rates i use........

10180 i use 0.2a
10440 i use 0.3a
14500 and 16340 you can use 0.3a or 0.5a(latter i use at 0.5a)
18650 1a(i use 1.5a for my IMR/INR cells when 2 or less, when charging 4x 18650's, i use the 1a as highest available for the 4 bays.
26650's i use 2a

AA loops 1a
AAA loops 0.3/0.5/0.7 even, i tend to use 0.5a


----------



## TinderBox (UK)

As others have said 200ma is too low, I normally charge at 0.5C so 2000mah cell gets charged at 1000ma, you can discharge at anything you like, but for standard industry capacity test i use 0.2C so that`s 400ma for an 2000mah cell.

I have just discharged 4 Eneloop 2000mah cells on my BT-C3100 and am now charging them at 1000ma, I will read the final voltage off the charger and then do an 0.2C discharge to determine the capacity and i will report back.

EDIT: It look like i had my charger set on test, so the cells charged to 1.51v according to the display and are now discharging at 700ma a little higher than the 0.2C of 400ma 

*RESULTS: 1984mah 1926mah 1903mah 1916ma not too bad for old cells 10 Year old "06-06L2" discharged at 700ma
*
John.


----------



## RI Chevy

I can only charge at 750 mAh max with my BC700. I have not noticed anything out of the ordinary with my Duraloops or Eneloops. They hold a charge well, and always seem to be fully charged.


----------



## TinderBox (UK)

My 4x Eneloop AA 2000mah charging at 1000ma are terminating at approx 1.51/1.52v on my BT-C3100

John.


----------



## ven

TinderBox (UK) said:


> My 4x Eneloop AA 2000mah charging at 1000ma are terminating at approx 1.51/1.52v on my BT-C3100
> 
> John.



About the same, they settle down after a bit and usually get around 1.47v after a few hours off the top of my head....................dont check again as may drop a bit more after a day!


----------



## TinderBox (UK)

I usually wait an hour or so for the battery to cool down and the voltage drop to stabilize a bit before i check the voltage.

*RESULTS: 1984mah 1926mah 1903mah 1916ma not too bad for 10 Year old cells "06-06L2" discharged at 700ma*

John.



ven said:


> About the same, they settle down after a bit and usually get around 1.47v after a few hours off the top of my head....................dont check again as may drop a bit more after a day!


----------



## MrWongBurger

Will the trickle charge when the battery is done damage eneloops? Im thinking about picking up this charger. The 2.2 one though


----------



## ChrisGarrett

MrWongBurger said:


> Will the trickle charge when the battery is done damage eneloops? Im thinking about picking up this charger. The 2.2 one though



I have the 3400 v. 2.2 and I believe that the consensus is is that trickle charging LSD (low self discharge) batteries like the Eneloops probably isn't the best thing for them. HSD batteries have a higher self discharge, so they can stand it.

My Maha C9000 does 'trickle' charge, but it's more of a final 2 hour stage, so built into the equation, so to speak. Batteries are at approximately 90% when the charger displays 'DONE' and the final two hours 'tops' them off.

Chris


----------



## MrWongBurger

Im guessing i should pass on this charger?


----------



## ChrisGarrett

MrWongBurger said:


> Im guessing i should pass on this charger?



Just do leave them on the charger for a month.

I got mine in January and it's a very well regarded charger and I have a bunch of good chargers.

Chris


----------



## Skeeterg

I have the 3100 v2.2 and the fan started making noise shortly after I got it. All I had handy was jb-80 so I sprayed some in the fan,and it took a couple of uses before the noise quit,and it's been running pretty quiet.


----------



## MrWongBurger

Yeah but is it good for LSD cells? thats what i would be using it for.


----------



## ChrisGarrett

MrWongBurger said:


> Yeah but is it good for LSD cells? thats what i would be using it for.



Of course it is. There are other good NiMH chargers, like my Maha C9000, but I don't feel cheated charging my NiMH batteries on my Opus BT-3400.

If you don't care to charge up lithium ion cells either now, or down the road, get the Maha C9000, would be my advice. They're about the same price from rdana on Ebay, who sells both, as well as others.

You'd have to leave your batteries on the 3400 for perhaps days, to potentially cause a problem, so don't do that.

Chris


----------



## MrWongBurger

Do any of them not trickle charge? Id rather have a charger that doesn't do that.


----------



## seery

They are now shipping with v3.1.

_April 14 2016: Now shipping BT-C3400 V3.1_

_What is the difference between bt-c3400 v2.2 and bt-c3400 v3.1? 

V3.1 changes the discharge algorithm to comply with industry best practice for discharge of Li-ion cells._


----------



## novasquid

who is "they"?


----------



## seery

A few sellers on Amazon and eBay have just made updates to their ads saying they are now shipping v3.1.


----------



## novasquid

thanks, i see it now on amazon, specifically the seller "DC Workshop." i wonder what that means, "industry best practice for discharge of Li-ion cells."


----------



## Gauss163

Can you please give a link to the Amazon page that says the improvement is ""industry best practice for discharge of Li-ion cells." Google search does not find it there.


----------



## seery

Gauss163 said:


> Can you please give a link to the Amazon page that says the improvement is ""industry best practice for discharge of Li-ion cells." Google search does not find it there.



Answered by DC Workshop.

http://www.amazon.com/forum/-/TxR57J4FANYGTR/-/ref=ask_dp_lsw_al_hza?asin=B00NR77SL2


----------



## ChrisGarrett

seery said:


> Answered by DC Workshop.
> 
> http://www.amazon.com/forum/-/TxR57J4FANYGTR/-/ref=ask_dp_lsw_al_hza?asin=B00NR77SL2



DC Workshop is Robert Dana and he's a pretty good guy. I've bought a lot of stuff from him over the past 4 years and he was kind and promptly sent me a couple of new wall warts when the OEM one crapped out on me.

He has the 3400 specifically branded for his customers.

Chris


----------



## seery

I asked DC Workshop "What does the newest version v3.1 offer over the older v2.2?". This is their response. 

"It is basically a change in the discharge for Li-ion cells. You will see the discharge for Li-ion cells terminate at 3.1V instead of 2.8V. This brings the charger in line with industry best practice for discharge. Most Li-ion cell data sheets specify 2.8V as minimum voltage for discharge. Best practice is to terminate discharge at 3.0V Because of the way this charger uses PWM for the discharge current it is better to use 3.1V. 

In the past some low quality cells would trip the internal protect circuit, especially at high discharge currents. That was not so much a charger problem as it is a cell quality problem but the charger gets blamed. That situation is much improved now. The discharge and capacity measurement are now closer to industry best practice instead of just general Li-ion cell data sheet specifications. In fact the change has little affect in the measurements. The protocols for NiMH/NiCd cells are not changed."


----------



## HKJ

seery said:


> It is basically a change in the discharge for Li-ion cells. You will see the discharge for Li-ion cells terminate at 3.1V instead of 2.8V. This brings the charger in line with industry best practice for discharge. Most Li-ion cell data sheets specify 2.8V as minimum voltage for discharge. Best practice is to terminate discharge at 3.0V Because of the way this charger uses PWM for the discharge current it is better to use 3.1V.



Funny explanation.
The 3.0 volt is probably related to power banks, where they often terminate at 3.0 volt, this way they can handle all types of LiIon batteries.
The 3.1 volt is probably because they measure voltage with the current off and due to that it will be higher.

But this also mean it will show too low capacity for most modern cells with 2.5 volt termination, they do have capacity below 3 volt, result will also be worse than my tests where I stop at 2.8 volt.


----------



## TinderBox (UK)

So will people who know be buying v2.2 of the charger instead of v3.1 so they can get a more accurate capacity results on li-ion.

John.


----------



## novasquid

i asked him if the 3100 model is still at v2.2, and only the 3400 model is at v3.1, and he said yes, as far as he knows only the 3400 is at v3.1.


----------



## Milw light

My 3400 is doing well, although I too feel its undercharging a little bit. Mine is the 2.2 & I got the 12v adaptor that I will try out this weekend.


----------



## Gauss163

TinderBox (UK) said:


> So will people who know be buying v2.2 of the charger instead of v3.1 so they can get a more accurate capacity results on li-ion.



Depends on what you mean by "accurate". The newer version will yield lower capacities closer to what the user will actually obtain in most devices, whereas the older version will yield higher capacities, closer to the chemical capacity (and closer to the datasheet-specified nominal capacity for new cells).

For most users the former value is probably more useful than the latter, since it corresponds more closely to the _usable _capacity in most (non-test) devices. But this change may be annoying to some (power) users who desire the capability to compare to datasheet specs.


----------



## vadimax

Do those version issues apply to the BT-C100?


----------



## TinderBox (UK)

Better off asking here.

http://www.candlepowerforums.com/vb...-Review-of-Charger-Opus-BT-C100-early-version

John.



vadimax said:


> Do those version issues apply to the BT-C100?


----------



## RVD98072

I recently purchased this charger/discharger to test a bunch of 18650 cells that I got from old laptop batteries.

I am trying to do a charge test to see how much capacity i have in each cell.

However, whenever I do a discharge, it only discharges down to about 3.5-3.6v/cell up? and after that it stops (current is 0mA). I expect this to discharge down to around 2.8-3.0v or so. I am discharging at a rate of 500mA.

Is there some kind of setting or something like that that I need to set up?

How does the charger know that I have an 18650 vs another battery? Does it detect it from the size when inserted into the holder?


----------



## HKJ

RVD98072 said:


> I recently purchased this charger/discharger to test a bunch of 18650 cells that I got from old laptop batteries.
> 
> I am trying to do a charge test to see how much capacity i have in each cell.
> 
> However, whenever I do a discharge, it only discharges down to about 3.5-3.6v/cell up? and after that it stops (current is 0mA). I expect this to discharge down to around 2.8-3.0v or so. I am discharging at a rate of 500mA.
> 
> Is there some kind of setting or something like that that I need to set up?
> 
> How does the charger know that I have an 18650 vs another battery? Does it detect it from the size when inserted into the holder?




Could it be that you are measuring the voltage after the discharge has stopped?

http://lygte-info.dk/info/BatteryLowVoltage UK.html


----------



## vadimax

Have received BT-C100 today. Could not notice any firmware version indication, but in "Charge-Test" mode it does not display any mAh during charge curve. As far as I know that means 2.2 release (2.1 had capacity indication in both directions).

26650 under test is charged to 4.205V. I guess this is OK.


----------



## TinderBox (UK)

The Opus BT-C100 is in the link below, unless you want comment from BT-C3100 owners.

http://www.candlepowerforums.com/vb/showthread.php?418394-Test-Review-of-Charger-Opus-BT-C100

John.



vadimax said:


> Have received BT-C100 today. Could not notice any firmware version indication, but in "Charge-Test" mode it does not display any mAh during charge curve. As far as I know that means 2.2 release (2.1 had capacity indication in both directions).
> 
> 26650 under test is charged to 4.205V. I guess this is OK.


----------



## Gauss163

HKJ said:


> But this also mean it will show too low capacity for most modern cells with 2.5 volt termination, they do have capacity below 3 volt, result will also be worse than my tests where I stop at 2.8 volt.



Probably, but not necessarily. It could yield more or less capacity than standard CC/CV. It's hard to predict in general how a pulsed discharge will interact with high-internal resistance in unhealthy cells (the case that the Opus fix is attempting to address). In some cases pulsing will result in less effective IR (so more capacity) because the longer-time scale components of IR don't have the time to fully ramp (as they do in CC) - something that will be familiar to anyone who has noticed the much longer times required for high IR cells to rebound to steady-state after load changes.


----------



## TinderBox (UK)

Just tried my v2.2 with an nihm AA and it shows the capacity during charge and discharge, but as you know the charging capacity will be off by around 20%

John.



vadimax said:


> Have received BT-C100 today. Could not notice any firmware version indication, but in "Charge-Test" mode it does not display any mAh during charge curve. As far as I know that means 2.2 release (2.1 had capacity indication in both directions).
> 
> 26650 under test is charged to 4.205V. I guess this is OK.


----------



## vadimax

TinderBox (UK) said:


> Just tried my v2.2 with an nihm AA and it shows the capacity during charge and discharge, but as you know the charging capacity will be off by around 20%
> 
> John.



Sorry, you've missed minor point: the difference between 2.1 and 2.2 indication is noticeable only in "Charge-Test" mode. Others are identical.


----------



## balloonshark

Currently I'm using the Maha MH-C9000 for my eneloops and a hobby charger for my Li-ions. I'm considering getting the Opus charger to go along with my Maha MH-C9000. What if any charger in the same price range should I be considering over the Opus BT-C3400? Or would it be better to grab cheaper separate AA/AAA and Li-ion chargers? If so I'm very open to suggestions.


----------



## ChrisGarrett

balloonshark said:


> Currently I'm using the Maha MH-C9000 for my eneloops and a hobby charger for my Li-ions. I'm considering getting the Opus charger to go along with my Maha MH-C9000. What if any charger in the same price range should I be considering over the Opus BT-C3400? Or would it be better to grab cheaper separate AA/AAA and Li-ion chargers? If so I'm very open to suggestions.



If you want some analyzing functionality in your li-ion charger, like you have with your Maha C-9000, the Opus 3400 v. 2.2 (I'd stick with this version vs. the newer v. 3.3, as it discharges to a lower voltage) is a good charger that will also do NiMH batteries, 4.35v cells and the 3.2v LiFePo4 chemistry (if you drill a hole in the bottom.) It's a 12v charger and will work with a car adapter, or 12v solar, like your Maha.

If you want to save a few bucks and don't care about 4 bays, or the discharge/analyzing features, the Xtar VP2 is a pretty flexible and efficient 12v charger.

There are others from Nitecore--D4/D2 that get good marks, but I have both of the above (among others) and they work fine.

Chris


----------



## balloonshark

ChrisGarrett said:


> If you want some analyzing functionality in your li-ion charger, like you have with your Maha C-9000, the Opus 3400 v. 2.2 (I'd stick with this version vs. the newer v. 3.3, as it discharges to a lower voltage) is a good charger that will also do NiMH batteries, 4.35v cells and the 3.2v LiFePo4 chemistry (if you drill a hole in the bottom.) It's a 12v charger and will work with a car adapter, or 12v solar, like your Maha.
> 
> If you want to save a few bucks and don't care about 4 bays, or the discharge/analyzing features, the Xtar VP2 is a pretty flexible and efficient 12v charger.
> 
> There are others from Nitecore--D4/D2 that get good marks, but I have both of the above (among others) and they work fine.


Thanks for your quick reply and suggestions. It looks like the C3400 is the best out of what you mentioned. The Nitecore D4 looks nice but it's not as flexible from skimming over a review. It also doesn't charge at 1A which I prefer.


----------



## ChrisGarrett

balloonshark said:


> Thanks for your quick reply and suggestions. It looks like the C3400 is the best out of what you mentioned. The Nitecore D4 looks nice but it's not as flexible from skimming over a review. It also doesn't charge at 1A which I prefer.



I've got a NC i4 v.2 (2014) charger and it's fine. I mostly got it because I had a credit and there was a little Xtar vs. NiteCore war going on here. Mine actually charges to 4.20v and while a bit slow with 4 cells inside, I can't complain.

We're in the golden age for batteries, cells and chargers. When I came here in the beginning of 2012, the Pila charger and 3100 NCR-As were the kings of the hill, lol. The Big 3 were AW, Redilast and CalliesKustom.

Times...they are a changin'.

Chris


----------



## markr6

ChrisGarrett said:


> I've got a NC i4 v.2 (2014) charger and it's fine. I mostly got when I had a credit and there was a little Xtar vs. NiteCore war going on here. Mine actually charges to 4.20v and while a bit slow with 4 cells inside, I can't complain.
> 
> We're in the golden age for batteries, cells and chargers. When I came here in the beginning of 2012, the Pila charger and 3100 NCR-As were the kings of the hill, lol. The Big 3 were AW, Redilast and CalliesKustom.
> 
> Times...they are a changin'.
> 
> Chris



Woah, Pila!!! That sure fell off the face of the Earth.


----------



## SilverFox

Hello Markr6,

Just a minute now... I still have and use a Pila charger.  

Tom


----------



## TinderBox (UK)

Does anybody have a link to an pdf of the v2.2 manual, my v2.2 C3100 came with an v2.1 manual and there are differences and all i can find online are old versons.

Thanks

John.


----------



## TinderBox (UK)

A quick tip, After i place identical cells in the charger, I run an quick test (this only take a few seconds), this check the internal resistance of the cells, the results should be close but if one cell is way off, remove the cell and replace, and redo the quick test, bad connection seems to give high resistance result, I do a quick test especially if i an using the D cell adaptors, If you still get high resistance on 1 cell try it in another slot, if you still get a HR then the cell is most likely bad and should be recycled.

John.


----------



## markr6

TinderBox (UK) said:


> A quick tip, After i place identical cells in the charger, I run an quick test (this only take a few seconds), this check the internal resistance of the cells, the results should be close but if one cell is way off, remove the cell and replace, and redo the quick test, bad connection seems to give high resistance result, I do a quick test especially if i an using the D cell adaptors, If you still get high resistance on 1 cell try it in another slot, if you still get a HR then the cell is most likely bad and should be recycled.
> 
> John.



Yeah I think selfbuilt mentioned that in one of his reviews. You can move/spin/wiggle the cell and get a different number every time. Good for a dirty estimate only. I'll usually get something anywhere from 70-100 on a 1 year old 18650.


----------



## hoanle

seery said:


> I asked DC Workshop "What does the newest version v3.1 offer over the older v2.2?". This is their response.
> 
> "It is basically a change in the discharge for Li-ion cells. You will see the discharge for Li-ion cells terminate at 3.1V instead of 2.8V. This brings the charger in line with industry best practice for discharge. Most Li-ion cell data sheets specify 2.8V as minimum voltage for discharge. Best practice is to terminate discharge at 3.0V Because of the way this charger uses PWM for the discharge current it is better to use 3.1V.
> 
> In the past some low quality cells would trip the internal protect circuit, especially at high discharge currents. That was not so much a charger problem as it is a cell quality problem but the charger gets blamed. That situation is much improved now. The discharge and capacity measurement are now closer to industry best practice instead of just general Li-ion cell data sheet specifications. In fact the change has little affect in the measurements. The protocols for NiMH/NiCd cells are not changed."



Thank you


----------



## novasquid

i'm sure i'm not the only one to ask or think about it, but i picked up some AA to D battery adapters and was wondering if there would be any issues to using it to charge up AA batteries in the opus? each D battery adapter holds 2 AA batteries, so using 4 D adapters, one could charge 8 AA batteries at a time. i'm sure it's not a good idea to do that, but i'm just not smart enough to know why it's a bad idea. 

AA to D battery adapters:
https://www.amazon.com/gp/product/B0094DH1E2/?tag=cpf0b6-20


----------



## TinderBox (UK)

D cells will not fit in the C3100, I had to buy an couple of D cell adaptor`s even then i think only slot 1 and 4 can be used.

I have charged 3AA to D adaptors in my C3100, but as i said above you have to buy an D cell adaptor.

The links below is just an examples you can buy them in lots of places for cheaper

[url]http://www.ebay.co.uk/itm/Parallel-AA-Battery-Adapter-Holder-1-5V-Case-Box-Converter-3-AA-to-1-D-Size-/222015850604?hash=item33b12d086c:g:QfgAAOSwzhVWtK45
[/URL]
Make sure you get parallel adapters, not serial ones or you will end up with double or triple the voltage






http://www.ebay.co.uk/itm/2-Pack-D-...BT-C2000-G8-/111925346788?hash=item1a0f4541e4

John.


----------



## novasquid

you're right, i didn't even test fit them to see if they would fit. and they don't fit at all. from reading other places, it looks like it's doable if it did fit, only restriction is that the charger has to be able to charge double the mAh.


----------



## TinderBox (UK)

If you use all 4 slots the maximum charge rate is 1000ma, a bit slow for D cells, But if you only use slots 1 and 4, you can charge up to 2000ma.

EDIT: If you get the D cell adaptors, to make sure you have a good connection when charging with you C3100, Do a "quick test", it only takes seconds and will show you the resistance of the cell and also show if you have a poor connection before you start to charge.

John.



novasquid said:


> you're right, i didn't even test fit them to see if they would fit. and they don't fit at all. from reading other places, it looks like it's doable if it did fit, only restriction is that the charger has to be able to charge double the mAh.


----------



## markr6

Still looking around for other chargers just out of curiosity. Nothing seems to beat this one for me.


----------



## ven

markr6 said:


> Still looking around for other chargers just out of curiosity. Nothing seems to beat this one for me.



There is more tec, more money to Mark, but still for me this offers best bang for buck............


----------



## kreisl

i whole heatedly aglee


----------



## ComputerTime

Hi, 

I looking for BT-C3400 v2.2, but I only found BT-3100 v2.2. Are they the same version? 

Regards.


----------



## TinderBox (UK)

They are the same.

John.



ComputerTime said:


> Hi,
> 
> I looking for BT-C3400 v2.2, but I only found BT-3100 v2.2. Are they the same version?
> 
> Regards.


----------



## ComputerTime

Thanks. Time to do more shopping.


----------



## TinderBox (UK)

Is there a version V2.2 of the manual in pdf format that i can download, my paper manual has v2.1 written on it.

Thanks

John.


----------



## Fuhgetaboudit

I see that on ebay a fellow is selling *Opus BT-C3400 V. 3.1* now. So where can one go to see just what the truth is here? Is there an Opus website that states what versions these Chargers are currently at?

http://www.ebay.com/itm/BT-C3400-V3...9206&clkid=8323246181028584054&_qi=RTM2247628


----------



## ven

IMHO save $10-$20 and get the v2.2 .............just a little change afaik with the firmware, does not discharge the cell as much(cant remember the figures but someone will). 2 sides to this, you wont get a full MAH capacity with the 3.1, but it is not as hard on the cell.........again imo it wont make much difference or noticeable difference in life anyway. Might prevent some protected cells tripping , not that i have read any issues of that.


----------



## TinderBox (UK)

Hi.

I bought 2x Olight RCR123A 650 mAh 3.7V

I charged them in my Opus c3100 v2.2 at 500ma, NO Problems

But as i try to discharge them at the lowest 200ma the display goes from showing the voltage to NULL within a second.

I am now discharging them in my SkyRC MC3000 without a problem.

So what is wrong with my C3100 v2.2 ??????????????????

Thanks

John.


----------



## HKJ

TinderBox (UK) said:


> So what is wrong with my C3100 v2.2 ??????????????????



Nothing wrong, but it is probably the PWM current regulation and a fast and sensitive over current protection on the cell.


----------



## TinderBox (UK)

HKJ said:


> Nothing wrong, but it is probably the PWM current regulation and a fast and sensitive over current protection on the cell.



Thanks Henrik, 

Good job i have my MC3000.

John.


----------



## ven

Better late than never and to save my lazy a55 going upstairs every time i want the 4.35 setting on the vp2, i decided to make a hole for the switch. Super easy, 4 screws, marked on case where to drill. Now to add, it was perfectly neat(drill hole) but too small and dont want to be sticking something small in to move switch. So a few holes and used drill to open up. No small file at hand and tbh i dont care as its covered anyway when sat down on base. Whilst there i swapped out the existing fan for the spare, a 10s job all in. Just slides out after unplugging. Old fan felt fine and smooth to spin, so not sure yet if the new fan will make a difference in the noise or not.

Its fugly, but i can easily switch


----------



## kosPap

I have done the same, and I woill suggest a safety measure (I practice)
Cover the hole with a piece of blue masking tape or somethign like it.
When you sett he charger at 4.35, place the tape near the screen as a reminder.
After charging ALWAYS return the switch at 4.2V and cover with the tape.


----------



## Climb14er

Getting my BT-C3400 v3.1 charger later on... replacing my plug in and run Pila IBC charger.

What charge and discharge settings do you recommend, safe and approx 3 hour, give or take, for Panasonic Sanyo 18650 GA 3500 unprotected cells and Panasonic Sanyo Orbtronic 18650 3500 protected cells?

I've got some 2900 and 3100 Orbtronic 18650 protected cells also... just trying to get an idea what others are using.


----------



## ven

1a rate is fine, could use 1.5a if you wanted without any issue(can use up to 3.5a if available, but will take a few cycles off the cells life).

Up to 1a discharge is fine also, if you want a little more gentle discharge then 0.5a.

If i am charging more than 2 cells, i use the 1a rate regardless of 18650, be it high drain or ICR. 

14500/16340 and 18350 i use 0.5a
18650 1a/1.5a
26650 2a


----------



## Climb14er

ven said:


> 1a rate is fine, could use 1.5a if you wanted without any issue(can use up to 3.5a if available, but will take a few cycles off the cells life).
> 
> Up to 1a discharge is fine also, if you want a little more gentle discharge then 0.5a.
> 
> If i am charging more than 2 cells, i use the 1a rate regardless of 18650, be it high drain or ICR.
> 
> 14500/16340 and 18350 i use 0.5a
> 18650 1a/1.5a
> 26650 2a



Excellent! Was thinking 1a on the charge and half that on the discharge.


----------



## ven

That will be fine and a little more gentle on the cell over 1a discharge. However it would be fine using either, it is a slow process so be warned..........Think on the second discharge I gave in, changed to charge and called it a day....literally :laughing:


----------



## lojden

Ordered "V2.2" from gearbest for $30, hope it is good


----------



## markr6

lojden said:


> Ordered "V2.2" from gearbest for $30, hope it is good



Awesome how the best (IMO) charger of this class is one of the least expensive. Still using mine exclusively. Sure wish it would have come along before I purchased all the others!


----------



## ven

lojden said:


> Ordered "V2.2" from gearbest for $30, hope it is good





Yes it is good, as with Mark nothing so far has come close for the money. I keep pondering the new xtar dragon, it costs 3 times as much and offers less charge rate options. Dont care for the probes really, novelty will wear off soon with them hanging around untidy. When my cell/s dont hold charge or last as long, i know resistance is built up too much and recycle time. No voltage read out when charging is not good for my needs either.............so right now, the v2.2 is still the charger for me, on day to day usage. Although it does a little too much singing and dancing for my needs, the skyRC mc3000 seems a more flexible option in the higher price category.


----------



## Coolfx

Hi,

I recently got 2 BT-c3100 v2.2 to test capacity or my powerwall project and I found the readings a bit weird.
I didn't noticed it first testing 2800-3000 mAh battery, given capacity of 1500 to 2800 seemed good, but I retested some old Samsung 26H I previously tested with a copy Imax b6 months ago (a lot were 2400-2500 on Imax) and now I got 2600-2700 at 1amp with these BT-C3100, more than the rated capacity of theses old cells.
I'm a bit confused about the readings of theses chargers, I checked the discharge current with my multimeter and got 0.78-0.9Amp fluctuating for 0.999-1Amp given at the charger screen. 
Can I assume the charger discharge below the rating it's supposed but think he's in the range and give a false capacity ?
I haven't found anyone with this concern with v2.2.


----------



## Gauss163

@Coolfx Double check to make sure that your AC adapter has sufficient power. This was the source of similar problems in earlier versions.


----------



## Coolfx

I use the 3Amp provided adapter, EU version. It seems the problem with power adapters was during the charging, discharging isn't supposed to require a lot of current from AC.


----------



## Gauss163

Yes, the earlier problems were with charging, which I thought was your case but double-checking I see yours has to do with discharging. Possibly some discrepancy may be due to different termination voltages but I would not expect that much. How were you measuring the current? Possibly your meter might not yield accurate results for pulsed loads.


----------



## UnknownVT

Coolfx said:


> I recently got 2 BT-c3100 v2.2 to test capacity or my powerwall project and I found the readings a bit weird.
> I didn't noticed it first testing 2800-3000 mAh battery, given capacity of 1500 to 2800 seemed good, but I retested some old Samsung 26H I previously tested with a copy Imax b6 months ago (a lot were 2400-2500 on Imax) and now I got 2600-2700 at 1amp with these BT-C3100, more than the rated capacity of theses old cells.
> I'm a bit confused about the readings of theses chargers, I checked the discharge current with my multimeter and got 0.78-0.9Amp fluctuating for 0.999-1Amp given at the charger screen.
> Can I assume the charger discharge below the rating it's supposed but think he's in the range and give a false capacity ?
> I haven't found anyone with this concern with v2.2.


I don't know how relevant this may be - 
1) mine is a v2.1 and
2) way back in Sept/2014 - 
I had one slot that gave significantly erroneous discharge readings, where the measurements were more than double the actual capacity when measured in another slot.

Please see Posts #55 and #59 (links) reported in this thread.


----------



## Coolfx

Gauss163 said:


> How were you measuring the current? Possibly your meter might not yield accurate results for pulsed loads.


Maybe my meter isn't accurate with pulse loads,I used my usual meter with 20Amp DC current capacity.


----------



## Coolfx

UnknownVT said:


> I don't know how relevant this may be -
> 1) mine is a v2.1 and
> 2) way back in Sept/2014 -
> I had one slot that gave significantly erroneous discharge readings, where the measurements were more than double the actual capacity when measured in another slot.
> 
> Please see Posts #55 and #59 (links) reported in this thread.



Thx for your feedback, did you find a way to solve the problem on this channel ?
1)Readings seems consistant between channels and units here, it's more like both chargers are badly calibrated.
2)I don't really trust the capacity given by my old Imax b6 copy as it's cheap chinese stuff but I appear more realistic with 2400-2500 (and maybe too enthusiast ?) for a at least 5 years old 2600mAh battery.
3)According to the mesured discharge current (86% min of displayed 1Amp) and the given capacity of 2700+ it should be a real 2300+mAh which seems possible for theses cells. If someone have an idea to check the capacity let me know.
4) I also have a Skilhunt M4D charger, I will try to charge some cells discharged on the BT-C3100 and compare charge/discharge capacity.


----------



## UnknownVT

Coolfx said:


> Thx for your feedback, did you find a way to solve the problem on this channel ?



No, never resolved. Got partial refund - so I have an Opus BT-C3100 V2.1 with 3 good channels (slot #1 one of the higher current ones is bad and I marked and just don't use it)

Since then I bought another (v2.1) when the price dropped.

My suggestion - if you are not satisfied with the charger - return for replacement or refund.


----------



## bltkmt

I have had this charger for a few months and love it so far. Have been slowly churning through my Eneloops, analyzing and charging them. I love being able to charge both battery chemistries without issue. Great tool!


----------



## er84

I bought this charger some days ago.

He is so great and seem to work find.

But when i plug the back power of charger i got some electrical sparks.

Should i be worried about that ?


----------



## Bdm82

er84 said:


> I bought this charger some days ago.
> 
> He is so great and seem to work find.
> 
> But when i plug the back power of charger i got some electrical sparks.
> 
> Should i be worried about that ?


Can happen with dc adapters. 
I find it best to plug the cord into the charger first, then the cord into the wall.
Great charger, though.


----------



## er84

Yes i will do it like this, seem more safe.

I also read its normal, its about the capacitor instant charging.


----------



## seanspotatobusiness

HKJ said:


> ...for normal charging I will still prefer a charger with non-pulsing CC/CV charging.



Does anyone know why HKJ prefers non-pulsing CC/CV charging? What's wrong with pulsing?


----------



## HKJ

seanspotatobusiness said:


> Does anyone know why HKJ prefers non-pulsing CC/CV charging? What's wrong with pulsing?



With smaller cells, you may charge with 10 times rated current in the pulses.
When the charge is nearly finished a pulsing charger will often charge with voltage above 4.2V.

Both are minor details, that is avoided with a non-pulsing charger.


----------



## Capolini

I like mine very much. I exchanged my original 2.2 for the one below which gives a slightly higher charge[0.02v] and is more accurate w/ capacity test!

*HKJ Tested:2884Mah for FT version


**DISCHARGE/CAPACITY RESULTS

Device: NEW Opus BT-C3100 2.2

Battery:Samsung INR18650 30Q- FT-3000mAh

Purchased:November 27th,2016

Discharged @ 1amp

Cycles:5
*






*Four slot average:2925mAh-HKJ-2884mAh-My Opus results are 1.5% higher than HKJ.
___________________________________________________________________________________________________________________
*
*DISCHARGE/CAPACITY RESULTS

Device: NEW Opus BT-C3100 2.2

Battery:Samsung INR18650 30Q-BT-3000mAh

Purchased:March 27,2017

Discharged @ 1amp

Cycles:1-Brand new-First cycle for this capacity test.
*





*Four Slot Average:2910mAh. Although it is a BT and Not a FT which is the only one HKJ tested, it is 0.9% higher than HKJ[2884mAh].*:thumbsup:
*______________________________________________________________________________________________________________________

**As you can see they are very close. The OLDER[4+Months] FT 30Q have a Four slot average of 2925mAh and the BT'S have a Four slot average of 2910mAh*


----------



## SoCalTiger

HKJ said:


> With smaller cells, you may charge with 10 times rated current in the pulses.
> When the charge is nearly finished a pulsing charger will often charge with voltage above 4.2V.
> 
> Both are minor details, that is avoided with a non-pulsing charger.



What is the practical impact of this? More wear/degradation of the cell over time I assume? Is there any impact to cell safety over time or just cell life? Or maybe no practically measurable difference at all?

It looks like the pulses are at a little over 2A - about 2.25A. So, for a 2Ah+ cell, no problem. But I can see how it can be problem for a smaller cell that is say, only 600mAh. The pulses are at ~4C in that scenario.


----------



## hatman

Has anyone compared the Opus 1000 with the 3400 for charging ability and speed?


----------



## The-J-Man

gyzmo2002 said:


> Results for the Opus:
> 
> Discharged capacity measured: 3502mah instead of 3252mah with the mc3000. The capacity measured with the Opus is too high than the cell specs.



In then process of testing hundreds of 18650s here and the results really are a bit high. Ive had several that the 3100 v2.2 says it's discharged 2200-2250 from a 2000 cell. 

Considering this inaccuracy seems normal I'm trying to find out as accurately as possible what percentage on top it seems to be. From my results I'm inclined on say about 15%. 
As you have the mc3000 would you mind running a few more tests so we could maybe establish an average percentage that I can take off the results from the 3100 so I know what my cells are so I can categorise them?

cheers mate


----------



## The-J-Man

People are saying the opus charges to 4.22v, mine definitely stops at 4.2, what gives?


----------



## Arizona_Mike

Mine stops a 4.2v as well. Might just be a tolerance issue. Most cells are specified +/-0.05v on he charge voltage.

Mike


----------



## ChrisGarrett

The-J-Man said:


> People are saying the opus charges to 4.22v, mine definitely stops at 4.2, what gives?



Chargers are all different.

I have some that charge to only 4.14v-4.15v (Xtar MP1S), some that charge over at (4.22v-4.23v (two Liitokala 100s) and finally, some that are just right--4.20v (Xtar XP1).


There's tolerance stacking even within the same model line there could be variances and then throw in the condition of the cells and batteries and things can be 'not always exact', shall we say? 

I even have two Liitokala 202s that I got at the same time and but for the extra bay, the 202s are identical in my eyes to the 100s, but both 202s consistently undercharge to the tune of ~4.18v, for all four bays! Even on the 4.35v setting for my LG D1s/E1s.

My Opus BT-3400 v. 2.2 seems to terminate right at 4.20v for the times that I've sat there and watched, with healthy cells coming off at 4.19v-4.20v and then settling down a bit after that, which is normal.

Spec for most cells is 4.20v (+/- .05v), so 4.15v-4.25v and the health/condition of the cells will matter a lot. That means where the charge curve stops and not where the cell is 24 hours later.

It used to be that the NiteCore i4 v.2 charger would exceed spec for many users posting here, to the point that some might not have been that kosher to use, but mine has been a perfect child...go figure?

Get a decent DMM, get a fresh battery for it and check this stuff initially, at least, so you know what's up.

Chris


----------



## The-J-Man

I just got myself a second one and the Voltage reading are terribly wrong. A 4.20v cell reads at 4.13v. My first charger reads it at 4.21v. 

Is it possible to calibrate these chargers, or is my unit just defective?


----------



## HKJ

The-J-Man said:


> I just got myself a second one and the Voltage reading are terribly wrong. A 4.20v cell reads at 4.13v. My first charger reads it at 4.21v.
> 
> Is it possible to calibrate these chargers, or is my unit just defective?



When people say this I always wonder what equipment the use to check the charger. The meter has to measure the voltage in the 0.2 second the charger turns the current off (My preferred meter for this is a Keithley DMM7510, but it is a bit expensive).

With that said the precision on these charger is not that good, but I believe somebody said it has a very rough calibration (Something with a solder bridge).


----------



## The-J-Man

HKJ said:


> When people say this I always wonder what equipment the use to check the charger. The meter has to measure the voltage in the 0.2 second the charger turns the current off (My preferred meter for this is a Keithley DMM7510, but it is a bit expensive).
> 
> With that said the precision on these charger is not that good, but I believe somebody said it has a very rough calibration (Something with a solder bridge).



I got some 40€ multimeter from amazon that had a 5star rating, its been just as accurate as some super fancy one I have at work. 
My first c3100 is a tiny bit high compared to the meter but the second is quite a but low. 

so there might be a chance to adjust how its calibrated?

I put some cells in it now to charge them, they are reading 0.02lower then my meter so im ok with that, lets see what they charge up to...


----------



## Nev

Mine was showing 4.2v when it was really 4.16v fully charged ,I did a bit of research on this forum & came across a thread that discussed desoldering the J1 solder blob , I did it and now it's only 0.01v off , it now shows 4.2v & my multimeter says 4.21v.


----------



## Capolini

Nev said:


> Mine was showing 4.2v when it was really 4.16v fully charged ,I did a bit of research on this forum & came across a thread that discussed desoldering the J1 solder blob , I did it and now it's only 0.01v off , it now shows 4.2v & my multimeter says 4.21v.




That is interesting.

My first one showed 4.20v. The DMM read 4.15v. I exchanged it for that and other reasons!

My new one reads 4.21v. DMM reads 4.18v. Plus its capacity results are much more accurate to specs. No complaints w/ this one.


----------



## Nev

I tried to find the thread so I could post a link to it ,but I can't find it ,I was only reading it 2 days ago.
I've got pictures of the circuit board where the J1 bridge is but I can't post pictures on this forum for some reason, I had to use a magnifying loop to spot it as it's very small.


----------



## Capolini

Nev said:


> I tried to find the thread so I could post a link to it ,but I can't find it ,I was only reading it 2 days ago.
> I've got pictures of the circuit board where the J1 bridge is but I can't post pictures on this forum for some reason, I had to use a magnifying loop to spot it as it's very small.



You have to use a Host to post pictures on here. I use postimage.org. It is simple and works much better and faster than photobucket which I used prior to Post image.


----------



## Nev

[/URL][/IMG]
j1 as it came



[/URL][/IMG]
this is after it's been de soldered.


----------



## Nev

[/URL][/IMG]


----------



## The-J-Man

Wow thats a tiny solder bridge!! how did you manage to fix that


----------



## Nev

With a 10x magnifying loup


----------



## Arizona_Mike

I'm going to double check my voltages but I think they are right on based on self discharge testing I've done on laptop cells. I never noticed a difference between the Opus and my multimeter.

I thought I'd read somewhere that the version 3.? only discharge tests to 3-something volts! 2.8 is plenty conservative in my opinion.

Mike


----------



## oneof

Hallo all, first time post here and longtime lurking.

Got a opus BT c3100 v2.2 and I am going through my old battery's....... Now a have the following set where something strange is going on....at least I think it is strange.....

4x 2600 GP Nimh

First time did a charge test

1379 mAh 1342 mAh. 1297 mAh 1389 mAh

Then I did a discharge refresh
In the same following

2602 mAh 2598 mAh 1703 mAh 2627 mAh

Now I could thing that the 3th battery is bad..but when it was doing it cycle in the charger it went up to 2624 so did it do a bad last charge.? Or is the battery bad? 

Any info would be highly appreciated

Thanks


----------



## tripplec

I would not be concerned with that cell if it came up. You could do a few more cycles on it and see if stays up to capacity. If you are using the cells in pairs etc match it with one thats similar but for general use the capacity is much higher than the typical eneloop LSD.


----------



## The-J-Man

Changed the internal switch to 4.35v setting but when I put in a cell that at 4.2v it says full. Tried with all 3 of my c3100 V2.2 and it didnt work on any of them. 
Any one know why?

the cells are ICR18650-30A /B


----------



## ChrisGarrett

The-J-Man said:


> Changed the internal switch to 4.35v setting but when I put in a cell that at 4.2v it says full. Tried with all 3 of my c3100 V2.2 and it didnt work on any of them.
> Any one know why?
> 
> the cells are ICR18650-30A /B



Run them down to 4.00v, or less and then start over, seeing what you see.

I think people reported a starting cutoff voltage where it wouldn't charge up further, than where it was.

Chris


----------



## tripplec

Sounds like a software bug to me then. Any battery previous charged and unused even after a few hours place in another chargere EG my I4 will charge topping as the last LED is flashing and eventually finishing with all lights on. Same goes for my SH4 the other way around.


----------



## ven

ChrisGarrett said:


> Run them down to 4.00v, or less and then start over, seeing what you see.
> 
> I think people reported a starting cutoff voltage where it wouldn't charge up further, than where it was.
> 
> Chris



+1

Might get away with 4.1v as I have, but yes it won't top back up to 4.35v if the cell is near 4.2v. Been using mine regular for 4.35v cells of late now I know !


----------



## The-J-Man

ChrisGarrett said:


> Run them down to 4.00v, or less and then start over, seeing what you see.
> 
> I think people reported a starting cutoff voltage where it wouldn't charge up further, than where it was.
> 
> Chris



Thanks!! popped some cells in that were at a lower voltage and they charged to 4.35 just fine!


----------



## markr6

On my 3100 v2.2, I noticed when running a Test on 4 18650s, it went: 1000mA charge, discharge (didn't check rate), then *500mA* for the final charge. I could have sworn it was 1000mA on the second charge other times I used this.

Update: never mind I just figured it out! When scrolling thru the screens I noticed all four bays say "418 mAh", which is impossible since they all started their second charging at different times. The charger obviously reset itself, maybe from getting too warm? Now that I think of it, I heard the fan get quiet and restart a couple times so I'm guessing it got too warm and restarted with the default 500mA. Same as if the power went out.


----------



## fmc1

Markr6


What you are seeing is also a classic symptom of an underrated or faulty power supply. It craps out exactly at the highest load point.


I had the same problem with my BT-C3100 V2.1. I was lucky because I was able to salvage a 12V 4A power supply from the trash. I had to change the output connector from a 5.5x2.5 to a 5.5x2.1 but it was no big deal. The reset issues all went away with the 4A power supply. 


You could also stager the loading of each slot. That’s what I did at first before I got the new PS. Put in one battery wait 15 min put in the next and so on. This way the transition from discharge to charge is at different times. This method helped but it was not a total cure.


Hopefully you have a supply from another device you can test with.


----------



## Gauss163

fmc1 said:


> What you are seeing is also a classic symptom of an underrated or faulty power supply. It craps out exactly at the highest load point [...]



Yes, this was discussed at length on BLF starting around here. Many users fixed this by purchasing a $10 new high-quality 66W LITEON SMPS that I recommended.


----------



## kosPap

anyone knows how the charger handles deeply discharged batteries?

I just tried a 18650 showing 1.27V and the charger started charging as usual.


----------



## tatasal

kosPap said:


> anyone knows how the charger handles deeply discharged batteries?
> 
> I just tried a 18650 showing 1.27V and the charger started charging as usual.



It's a smart charger. If you choose a charging rate which is too high for the cell to safely accept it, the charger will automatically lower the charging rate to a safe level until the cell recovers and the charger then goes back up to the chosen charging rate.

For example, choosing a charging rate of 1A will not be followed by the charger until it senses that the cell can safely accept such rate. It will automatically hover between .1A to .3A... just click till the Display shows MA..you will see the charging rate as it progresses.


----------



## Gauss163

kosPap said:


> anyone knows how the charger handles deeply discharged batteries?



Most Li-ion chargers (likely including the BT-C3100) incorporate a precharge phase that attempts to safely recover cells that have been overdischarged. Typically cells are precharged at a very low rate (e.g. C/10), which helps to recover the crucial SEI passivating layer (which may have dissolved after long storage in a deeply-discharged state). Precharge usually terminates around 3V, at which time the normal CC/CV charge starts. If the precharge doesn't reach 3V in some configured time (e.g. half-hour) then an error is signaled (possible internal short, or other major failure). See this post for more on precharging.

Above the charge rate C/10 means Capacity over 10, so if they are 2500mAh Capacity then C/10 = 2500/10 = 250mA.


----------



## kosPap

thanks Gauss.
I thought most intelligent chargers did not allow recharging of an overdischarged cell. So it came as a surpise the Opus did.


----------



## Gauss163

kosPap said:


> thanks Gauss.
> I thought most intelligent chargers did not allow recharging of an overdischarged cell. So it came as a surpise the Opus did.



It depends upon the depth of overdischarge. I don't recall the limits for the Opus, but if iirc they were mentioned in some of the earlier threads (and, of course, they can be determined by testing).


----------



## TinderBox (UK)

With firmware V2.2 it discharges 3.7v li-ion to 2.8 volts and firmware V3.1 discharges to 3.1 volts, It`s been a while since i used my C3100 V2.2 so i might be wrong.

John.


----------



## joelbnyc

This thread is giving me second thoughts on the Opus BT-C3100 V2.2 I just ordered...

Is this charger any use for measuring capacity? If not, can anyone recommend a capacity-measuring device or charger that is precise, accurate, and relatively user-friendly? Maybe the XTar VP4?


----------



## ven

The v2.2 is fine joel, if anything you get a more accurate reading. Most manufacturers state their MAH from min 2.5 or 2.7v, the v2.2 takes it down to 2.8v. The reason i believe they increased the voltage to 3.1v was due to issues with poor quality cells and PCB tripping.


----------



## tatasal

joelbnyc said:


> This thread is giving me second thoughts on the Opus BT-C3100 V2.2 I just ordered...
> 
> Is this charger any use for measuring capacity? If not, can anyone recommend a capacity-measuring device or charger that is precise, accurate, and relatively user-friendly? Maybe the XTar VP4?



The VP4 is just a 'straight-up' charger. It does not have the analyzing function like the Opus. 

I have the Opus too and you can't go wrong with it. Very user-friendly! (and I have other analyzing chargers too like the SkyRC MC3000, etc. for that matter)

In the VP4, the channels are not independent of each other, unlike the Opus (different modes, rates, etc. can be set ALL at the same time regardless of battery chemistry).


----------



## joelbnyc

Thanks ven and tatasal.

Since ordering the Opus, it dawned on me, though, that recording discharge curves on PC and comparing them to HKJ's would be best tool to distinguish fake/genuine cells...

I am now considering a SkyRC M3000 for this. But maybe this is overkill just to try to determine whether 8x button top 30Q's are real, although it would have uses down the road.

And maybe I'd really need at minimum a CBA like this even to attempt to replicate HKJ's discharge curves? http://www.westmountainradio.com/product_info.php?products_id=cba4


----------



## tatasal

joelbnyc said:


> Thanks ven and tatasal.
> 
> Since ordering the Opus, it dawned on me, though, that recording discharge curves on PC and comparing them to HKJ's would be best tool to distinguish fake/genuine cells...
> 
> I am now considering a SkyRC M3000 for this. But maybe this is overkill just to try to determine whether 8x button top 30Q's are real, although it would have uses down the road.
> 
> And maybe I'd really need at minimum a CBA like this even to attempt to replicate HKJ's discharge curves? http://www.westmountainradio.com/product_info.php?products_id=cba4



The CBA is a pure analyzer, it will only do discharge tests, does not even charge. If you are fine with it, then it will serve its purpose.

You mentioned about distinguishing fake/genuine cells...well, a simple discharge test on the Opus will easily tell you one. The MC3000 is just too much over-kill, (and hyped) for all intents and purposes, much more with the CBA.

My iCharger hobby charger can also provide PC-interface for graphing purposes via Logview, and it's supplied with a cable.


----------



## joelbnyc

tatasal said:


> The CBA is a pure analyzer, it will only do discharge tests, does not even charge.  If you are fine with it, then it will serve its purpose..



Yes I realize it's not a charger. Prob more useful if one has a whole bunch of cells for hobby/biz/resale purposes. For my budget/uses I'll prob just wait until liionwholesale/mtn gets the button top 30Q's/VTC6's back in stock.



tatasal said:


> You mentioned about distinguishing fake/genuine cells...well, a simple discharge test on the Opus will easily tell you one.



I guess you're right, if it is accurate/precise- I could plot the Voltage vs mAh discharged on a graph by hand or in a spreadsheet, at a few points during the discharge, to see roughly how they compare to HKJ's tests of the genuine article?







Although I imagine a computerized graph using SkyRC M3000 would be easier. I looked at the ichargers too. But, if I can create a graph like this for $90 with the SkyRC...


----------



## arjay_18

Hi, been trying to decide between this charger and the maha C9000. Can anyone suggest which one to get? Is this charger "safer" and have more functions than the maha?


----------



## tatasal

arjay_18 said:


> Hi, been trying to decide between this charger and the maha C9000. Can anyone suggest which one to get? Is this charger "safer" and have more functions than the maha?



Well. the Maha is purely nimh analyzing charger only, but the Opus do can li-ion too.


----------



## SKV89

How does the Opus BT-c3100 v2.2 compare to the Xtar Dragon VP4 Plus? I just ordered the Opus but having second thoughts now after reading this. I'm not sure if pulse charging is good for the batteries.

Can anyone recommend me the best/safest charger?


----------



## tatasal

SKV89 said:


> How does the Opus BT-c3100 v2.2 compare to the Xtar Dragon VP4 Plus? I just ordered the Opus but having second thoughts now after reading this. I'm not sure if pulse charging is good for the batteries.
> 
> Can anyone recommend me the best/safest charger?



The Xtar is not an analyzing charger. It can only charge, and once a charging rate is chosen, it applies to all bays at once. The Opus on the other hand has 4 purely-independent channels.

With regards to pulse charging, I have yet to read any definitive end-user observation on whether a cell charged in another way (CC/CV) will actually last longer (lifetime-wise), or the other way around. There are also studies saying that pulse charging is actually better on cells.

http://www.sciencedirect.com/science/article/pii/S0378775301008205

https://smartech.gatech.edu/handle/1853/56262


----------



## Gauss163

tatasal said:


> The Xtar is not an analyzing charger. It can only charge [...]



But, since Li-ion typically has charge (coulombic) efficiency > 99%, you don't really need an analyzing (dis)charger to test capacity, since if your charger reports 3000mAh for a full charge then you know that the capacity is between 99% - 100% of that, i.e. between 2970 - 3000mAh (and that 1% error range is less than the typical 5% error range of the charger components / calibration). But that won't work so well for less charge efficient chemistries such as NiMh.


----------



## sbj

tatasal said:


> The Xtar is not an analyzing charger. It can only charge,...


 This statement is wrong. The VP4 Plus is still an analyzing charger. It can measure the internal resistance, discharge and indicate the discharge capacity.

http://lygte-info.dk/review/Review Charger Xtar VP4 Plus Dragon UK.html


----------



## tatasal

sbj said:


> This statement is wrong. The VP4 Plus is still an analyzing charger. It can measure the internal resistance, discharge and indicate the discharge capacity.
> 
> http://lygte-info.dk/review/Review Charger Xtar VP4 Plus Dragon UK.html



Sorry, I had in my mind the VP4 model (not the VP4 Plus), which does not have this feature.

http://lygte-info.dk/review/Review Charger Xtar VP4 UK.html


----------



## sbj

Can happen. The name is very similar.


----------



## stigma45

Hello,
I need help choosing between XTAR DRAGON VP4 Plus and OPUS BT-C3100 v2.2.
I'm mostly interested in charging batteries, everything else is a bonus.
I read that OPUS has problems with power supply unit.


----------



## lumen aeternum

I'd also like an analyzing charger, just to fool around with. Opus vs Dragon seems to have the highest wordcount.

Mainly I want to charge AAA NiMH without them getting hot -- I bought a couple dozen Tenergy last fall, and in my NiteCore Intellicharger i4 one of a pair will often be hotter, or both pretty hot.


----------



## ChrisGarrett

lumen aeternum said:


> I'd also like an analyzing charger, just to fool around with. Opus vs Dragon seems to have the highest wordcount.
> 
> Mainly I want to charge AAA NiMH without them getting hot -- I bought a couple dozen Tenergy last fall, and in my NiteCore Intellicharger i4 one of a pair will often be hotter, or both pretty hot.



The Xtar Dragon will offer more features than the Opus BT-3100 v. 2.2, but consult HKJ’s test for the precise pros and cons.

I have ~12 Xtar chargers, but not the Dragon, so I’m an Xtar fanboy. I’ve had the Opus BT-3400 v. 2.2 for 4 years and it’s pretty much the same as 3100 v. 2.2, but with a beefier fan and a display that can be toggled on/off. You can even drill a hole in the bottom of the case and access a slider switch for 3.8/4.35v cells!

Chris


----------



## John D

Hi: This is my first post.

I just purchased an Ambient climate c3000 battery charger (identical to the opus bt-c3100 v2.2.)
When using the charge-test mode, after the first charge, the capacity only shows four dashes. While this might be ok, the reason I'm questioning it is twofold:

1- In HKJ's review (post #1), he says display shows 1882mAH at 2.08. My charger shows -- --
I copied the info below from the first post but the image isn't showing for some reason.



Start HKJ copied text:
"CHARGE TEST NiMH batteries, used to measure capacity






This function charger, discharges and charges again and is used to measure the capacity of cells.
Display shows: 1892mAh 2:08" end HKJ copied text


2- When using the discharge- refresh mode, during the discharge portion, accumulated mAh is displayed as a progressing number. However, during the discharge phase of the test mode, only -- -- is displayed under accumulated mAh. 
Just wondering if my charger is working as it should?

Thank you


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## twist3r

Hello

I'm close to buying one discharger (and I'm torn between Liitokala 500 and v2.2 of Opus 3100). I read HKJ's review about Opus 3100 v2.1 (and I also read review about Liitokala 500). But... I coudn't find his review of Opus 3100 v*2.2* at his website. I guess thats because there is no review (done by him) about that software version of Opus 3100 (v2.2).

Can someone tell me (personally I would like if HKJ finds time to answer) what has changed from v2.1 to v2.2 and is that version of discharger 'better' than v2.1 or did it introduced some 'bad things' (compared to v2.1).


I would go for Liitokala 500 (because is cheaper) as my first (ever) smart charger/discharger, BUT... the fact that it doesn't measure internal resistance correctly, kinda stops me from that, and force me to re-think.

This is a topic about Opus BT-C3100, so I guess owners of it (even newer v2.2 ) would suggest me Opus over Liitokala, but... can I go wrong with Liitokala? I mean, how bad it can be becaues it can't measure IR correctly? That would mean that it can't measure capacity correctly, right? (sorry for noobish questions).

btw. I also heard that IF I decide to go with Opus v2.2 that I should buy one which has patent ID at the back? Why is that?

Thanks in advance for your answers guys.

p.s. currently Opus v2.2 at AE is $31.08 (witch includes shipping with tracking #) compared to $16.28 for Liitokala 500 (witch comes with free shipping that includes tracking #). Thats the cheapest prices I found from reliable sellers, so for a price of Opus I can almost buy 2x Liitokala. Is the Opus that much 'better' or should I go with Liitokala? Sorry for this offtopic question.


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## CNR

Man, i was looking to replace my old i4 charger and thought UMS4 or SC4 would be great, but after reading the reviews the time sharing and inconsistent IR readings put me off, it seems the BT-C3100 V2.2 is way better in all except of the pulse charging that worries me. 
I just need a fast (at least 1A x 4 18650s) charger that is safe for the batteries and with consistent (even if not very accurate) IR and mAh readings. Being able to discharge and measure capacity is a bonus, i can get the C3100 for 45€ with shipping, is there a charger like this without pulse charging ?


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## xzel87

CNR said:


> Man, i was looking to replace my old i4 charger and thought UMS4 or SC4 would be great, but after reading the reviews the time sharing and inconsistent IR readings put me off, it seems the BT-C3100 V2.2 is way better in all except of the pulse charging that worries me.
> I just need a fast (at least 1A x 4 18650s) charger that is safe for the batteries and with consistent (even if not very accurate) IR and mAh readings. Being able to discharge and measure capacity is a bonus, i can get the C3100 for 45€ with shipping, is there a charger like this without pulse charging ?






twist3r said:


> Hello





twist3r said:


> I'm close to buying one discharger (and I'm torn between Liitokala 500 and v2.2 of Opus 3100). I read HKJ's review about Opus 3100 v2.1 (and I also read review about Liitokala 500). But... I coudn't find his review of Opus 3100 v*2.2* at his website. I guess thats because there is no review (done by him) about that software version of Opus 3100 (v2.2).
> 
> Can someone tell me (personally I would like if HKJ finds time to answer) what has changed from v2.1 to v2.2 and is that version of discharger 'better' than v2.1 or did it introduced some 'bad things' (compared to v2.1).
> 
> 
> I would go for Liitokala 500 (because is cheaper) as my first (ever) smart charger/discharger, BUT... the fact that it doesn't measure internal resistance correctly, kinda stops me from that, and force me to re-think.
> 
> This is a topic about Opus BT-C3100, so I guess owners of it (even newer v2.2 ) would suggest me Opus over Liitokala, but... can I go wrong with Liitokala? I mean, how bad it can be becaues it can't measure IR correctly? That would mean that it can't measure capacity correctly, right? (sorry for noobish questions).
> 
> btw. I also heard that IF I decide to go with Opus v2.2 that I should buy one which has patent ID at the back? Why is that?
> 
> Thanks in advance for your answers guys.
> 
> p.s. currently Opus v2.2 at AE is $31.08 (witch includes shipping with tracking #) compared to $16.28 for Liitokala 500 (witch comes with free shipping that includes tracking #). Thats the cheapest prices I found from reliable sellers, so for a price of Opus I can almost buy 2x Liitokala. Is the Opus that much 'better' or should I go with Liitokala? Sorry for this offtopic question.





I have been using the v2.1 version going on 7 years now and my batteries are fine. I have 4 9 year old 2000mah eneloops and they are still fine despite being charged at 1A x 4 and 2Ax2. All my other Li-Ion cells are also fine with no obvious deterioration (I top up my stored batteries every month), those in cycle gets charged when low.

v2.2 should be the same if not better, the only modification I would recommend is to get a 6A power adaptor (2.5mm x 5mm barrel plug, please reconfirm though I may have remembered wrong), buy some spare fans (it gets loud after some time, maybe can be relubed but I already had spares so I didn't bother relubing the fan bearings). I also cut out the slots at the back to allow more airflow through the unit. If you can't be bothered doing all that bear in mind that I was using it stock up till 2020, then I got the 6A adaptor and the mods.

PS: There's a tiny switch at the back of the unit to switch li-ion charging between lifepo (3.2V), regular Li-Ion (4.2V) and 4.35V.....I made a cut out on mine to easily access the switch as I have a bunch of 4.35V cells.


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## ChrisGarrett

I’ve got both the BT-3400 v. 2.2 and the latest 3.1 and they’ve both been great chargers.

Chris


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## markr6

Solid. Still using mine pretty hard. The only time I use a different charger (C801D) is when I need to do more than 4 cells at a time.


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