# Test/Review of Analyzing Charger Powerex MH-C9000



## HKJ (Jun 20, 2014)

[size=+3]Charger Powerex MH-C9000[/size]















This charger it not a new charger, but has been on the market for many years. It has been the reference NiMH analyzing charger for many people.








 



I got the charger in a cardboard box.






The box contains the charger, a power supply (US plug, but universal voltage) and a instruction sheet.
The instruction sheet does a good job on explaining the charger.






The power supply is connected to the back of the charger with a standard barrel connector. I requires 12 volt 2A.






The user interface is four buttons and the display. It is only active when there is one or more batteries in the charger and then the background light on the display is on (I like this).






When powering the charger up all elements on the display is turned on while the numbers count from "00.00" to "99.99".









When putting a battery in the charger the "MODE" text will start flashing and the desired mode can be selected with arrow up and arrow down and confirmed with ENTER, then the current is selected, again with arrow up/down and ENTER. Depending on mode there can be from one to 3 selections. If no selection is made the charger will automatic start a charge cycle with 1A after some seconds.
The modes are:

CHARGE: Normal charger, it is possible to select from 0.2A to 2A in 0.1A steps, default value is 1A.
REFRESH ANALYZE: Charge, discharge, charge, both charge and discharge can be selected.
BREAK-IN: Charge, discharge, charge in a slow cycle, the battery capacity is specifyed from 0.5Ah to 20Ah in 0.1Ah steps.
DISCHG: Discharge the battery, rate is selected from 0.1A to 1A in 0.1A steps.
CYCLE: Charge, discharge a number of times, both charge, discharge and cycles are specified.

The slot button is used to select what slot to view on the display. When pressed the next slot will be selected and the display will show "mAh", after a short time it will show "ma", "min", "volt" and optional "cyl", then change to the next slot and repeat.
Usual the most interesting value to check is mAh and the slot button will select that for each slot in turn.






It is possible to tilt the charger for better cooling and better view of the display from a low position.













The charger has separate positions for AA and AAA batteries and a thermo sensor for each battery.

















The charger is not supplied with any adapters to handle C and D cells, but it can handle up to 20Ah batteries, i.e. it will work with adapters.



[size=+2]Measurements[/size]



Discharges with 0.8mA when not connected to power 
Charge will restart charging after power loss or battery insertion. 
Display light is on as long as there is a battery in the charger.
Voltage readout matches my DMM within 0.01V using "min" on the DMM, to catch the voltage when current is off. 
Except for discharge mode, all other modes will apply trickle charge when finished.
The charger will start, even if the battery voltage is 0 volt.


[size=+1]CHARGE: NiMH charge[/size]

Normal charge of a battery, the current can be select from 0.2A to 2A in 0.1A steps.
When finished the display will show the charged capacity, excluding top-off charge. This value can be below or above the actual battery capacity (NiMH batteries are usual charged with more mAh than they are rated for).






The charger uses about 2 hours to charge the battery, then it terminates on voltage and uses another two hours to top the battery, before it switches to a trickle charge. The charger will report done after the first two hours.














The 3 other slots works the same way. Notice that the temperature curve is mostly missing the typically "end of charge" increase, it only looks like there is one or two dots increase at the end of the top off charge. This makes me wonder if the batteries are completely filled or if there could be slightly more mAh in them.






Not much difference when doing a 200mA charge.










The XX and AAA eneloop does also look the same, except for the charge time.






Four batteries with 2A charge for each battery, this does generate some heat, but it looks like the termination is still done on voltage.






M1: 48,9°C, M2: 56,8°C, M3: 54,3°C, M4: 47,1°C, HS1: 69,3°C
It is no surprise that some chargers uses a fan. This charger has no fan and do get rather warm when charging.






The current from the power supply is also pulsing, with an average current of about 1.5A.






The charger uses pwm to adjust the charge current, each pulse is charging with 2A.






For 1A charge this means 50% duty cycle. The duty cycle is not exactly 50%, but slightly below, this means that the charge current is slightly below 1A.






And at 2A the duty cycle is below 100% and this makes the current slight below 2A.






Is the 2A charge pulse current due to a specific battery voltage or is it fixed. I uses a shorted battery and tried measuring the current again. It did not change, but was still 2A. This means the charger is using some sort of "constant current" circuit, not just a resistor for the charge current. This helps to limit the maximum current pulses. This is a good way to limit maximum current in pulses.






The top off charge looks like normal charging, but the pulses is shorter, the average current is about 0.1A and is applied for about 2 hours, i.e. about 200mAh.






Trickle charge uses the same 2A pulses, but they are even shorter.






Here I have zoomed in on a single trickle charge pulse. It is about 0.005 second long with 2A current and occur every other second, this gives an average of 5mA (The datasheet for the charger says 10mA). A nice low trickle current.






If a battery is put into the charger or it is powered on with batteries in it, it will start charging after some time.
It starts by applying a 10 second high current pulse (This is always the case when charging is started), probably to check for alkaline batteries. If it registers to high voltage after that pulse the display will show "HIGH" and the charge will terminate.



[size=+1]REFRESH ANALYZE: NiMH single cycle[/size]

This mode will charge the battery, then discharge and finally charge again. Both the charge and discharge rate can be selected.
When finished the display will show the discharged capacity.






As can be seen the charge cycles includes the top off charge and there is a rest after the discharge.



[size=+1]BREAK-IN: NiMH Slow cycle[/size]

Break-in will first charge the battery for 16 hours with 0.1C, then discharge the battery with 0.2C (This will take about 5 hours) and finally charge again with 0.1C for 16 hours. The capacity of the battery is selected from 0.5Ah to 20Ah in 0.1Ah steps. When finished the display will show discharged capacity. 
This method over charges the battery, before measuring capacity, this means it will always get the highest possible value. 
This method is used by IEC for measuring battery capacity.






This is a slow procedure, taking about 39 hours. In this case here I started with a full battery, but it does still get the full 16 hour charge. It can be seen on the temperature curve when the battery is full.



[size=+1]DISCHG:: NiMH discharge[/size]

Discharge will drain the battery, while measuring how much capacity was left in the battery. The discharge rate must be specified between 0.1A and 1A in 0.1A steps.
For measuring the full capacity of a battery the "REFRESH ANALYZE" mode will often be more useful, because it includes charging.






A 0.1A discharge does not generate any heat. The discharge was supposed to terminate at 0.9 volt, but terminates somewhere between 1.0 and 1.1 volt.






A single battery at 0.5A is also fairly cool when discharged.






But four batteries at 1A will generate some heat.






M1: 49,5°C, M2: 47,8°C, M3: 41,2°C, M4: 41,7°C, HS1: 67,6°C
Running discharge at full current on all four channels will heat the two center batteries significantly.






Discharge is also controlled with pwm, here is the lowest discharge current.






And the highest discharge current.


[size=+1]CYCLE: NiMH cycles[/size]

The cycle function will do repeatedly charge and discharge cycles. When finished a final charge is applied.
Both charge, discharge and number of cycles must be specified. The cycles can be between 1 and 12.
It is possible to read the capacity of all the discharges when finished: Use the arrow keys to select cycle and wait a moment before the discharge capacity is shown.






In the above curve I did two cycles (i.e. two dischargers). Charge current at 1A and discharge current at 0.5A. The charger adds top-off charge and a pause after each discharge.



[size=+1]Alternate test[/size]

I wanted to compare the different capacity analysis methods, all the test below is done with the same eneloop AA battery and in the sequence they are listed. Between each line there is a couple of hours rest with trickle charge.






The "break in" function charges 3200mAh into the battery.
The "top-off" charges about 200mAh extra into the battery.
It looks like ordinary charge + top-off will nearly fill the battery.




[size=+2]Conclusion[/size]

The charger does not use -dv/dt termination, but constant voltage with a top off charge and has the temperature sensor as backup. With the top off charge it looks like the charger just fills the batteries.
The function in the charger works very well and looks like they are designed for practical usage (i.e. they always shows the discharge capacity, not the charge capacity).
The user interface on this charger is easy for normal charging of AA batteries (Just put the batteries in the charger, everything else is automatic), but for doing something more special it can require a lot of key presses for each battery.

The charger is very good for analyzing batteries, but for normal charging the batteries might not always be filled.



[size=+2]Notes[/size]


The charger was supplied by Danaco for review.

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


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## TEEJ (Jun 20, 2014)

Very nice job!


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## Dubois (Jun 21, 2014)

Great to see this old charger being properly tested and reviewed at last. Thanks for this.


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## Ratton (Jun 21, 2014)

Thanks for the review! I have been putting off getting an AA charger, but this looks like the right on.:twothumbs


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## lowks (Jun 21, 2014)

Now waiting for HKJ to get to LaCrosse ...


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## HKJ (Jun 21, 2014)

lowks said:


> Now waiting for HKJ to get to LaCrosse ...



I have tested the 1020, but the review is not published yet. I do not know when I will publish the review.


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## SilverFox (Jun 21, 2014)

Hello HKJ,

Excellent review.

The C9000 is capable of -dV termination, but the voltage limit is usually hit prior to the -dV signal. I have seen the -dV termination on new cells on the first charge and on older cells that have problems. Other than that the voltage limit is hit prior to the full charge needed to trigger the -dV signal.

With new cells (other then Eneloop cells) I use the Break In to go through 2 charge cycles and that is usually enough for the cell to behave properly during additional charge cycles.

Tom


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## lowks (Jun 23, 2014)

HKJ said:


> I have tested the 1020, but the review is not published yet. I do not know when I will publish the review.


 How was the result yayy or nay ?


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## HKJ (Jun 23, 2014)

lowks said:


> How was the result yayy or nay ?



You will have to wait for the review, it is seldom possible to give a y/n answer, usual there are a couple of grays in it.


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## Mr Floppy (Jun 24, 2014)

> It starts by applying a 10 second high current pulse (This is always the case when charging is started)



Wow, it always seemed a lot quicker than that. Usually I wait until I get that voltage reading before inserting the next battery but it never seems to be that long. What happens if the voltage is high, does the it still apply the full 10 seconds?


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## HKJ (Jun 25, 2014)

Mr Floppy said:


> What happens if the voltage is high, does the it still apply the full 10 seconds?



I did not test that, but I expect it will break immediately when the voltage is high.


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## 18650 (Jun 29, 2014)

Nice review.

Can you comment on the AAA charging slots?

The AAA slots on my C9000 are extremely flaky. Any slight bump or movement of the charger causes random slots to go out as if no battery were present. I have to physical move the battery slightly to get it to register again with the charger acting as if I inserted a fresh battery.

The AA slots work flawlessly on mine save for the magic of SLOT 1.


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## HKJ (Jun 29, 2014)

18650 said:


> The AAA slots on my C9000 are extremely flaky. Any slight bump or movement of the charger causes random slots to go out as if no battery were present. I have to physical move the battery slightly to get it to register again with the charger acting as if I inserted a fresh battery.



I have never noticed any problem with the AAA slots (I have been using a C9000 for some years).


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## Viking (Jun 29, 2014)

18650 said:


> Nice review.
> 
> Can you comment on the AAA charging slots?
> 
> The AAA slots on my C9000 are extremely flaky. Any slight bump or movement of the charger causes random slots to go out as if no battery were present.




I have never experienced anything like that. But must admit my charger usually is placed at a stable surface.

I have therefore inserted 4 AAA in the all the slots , and while charging moved the charger quite violently around from place to place.
I have also placed it on the floor while jumping right next to it. Nothing happens , my charger keeps charging on all four slots.

My unit was produced in February 2012. However I know maha has upgraded the contacts sometime before my unit was produced.
When was your unit produced ? ( serial number ).


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## 18650 (Jun 30, 2014)

Viking said:


> I have never experienced anything like that. But must admit my charger usually is placed at a stable surface. I have therefore inserted 4 AAA in the all the slots , and while charging moved the charger quite violently around from place to place. I have also placed it on the floor while jumping right next to it. Nothing happens , my charger keeps charging on all four slots. My unit was produced in February 2012. However I know maha has upgraded the contacts sometime before my unit was produced. When was your unit produced ? ( serial number ).


 Is the number that begins with "0K" on the back the serial?

Unfortunately for me I only discovered this oddity recently because I never used it to charge AAA cells (too many button presses req'd so I used a Sanyo rapid charger instead).

If it were only violent movements that caused problems it wouldn't be an issue at all.

However something as simple as placing one cell and punching in the 400mA is enough to disrupt the charging of any random AAA already placed and set. It pretty much makes the C9000 useless for my AAA's.


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## HKJ (Jun 30, 2014)

18650 said:


> However something as simple as placing one cell and punching in the 400mA is enough to disrupt the charging of any random AAA already placed and set. It pretty much makes the C9000 useless for my AAA's.



Maybe you are not placing the cells correctly?


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## Viking (Jun 30, 2014)

18650 said:


> Is the number that begins with "0K" on the back the serial?



Yes "0K" makes it a 2011 unit. But if it is that sensitive I don't think the earlier designed contacts can be the reason.


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## 18650 (Jun 30, 2014)

HKJ said:


> Maybe you are not placing the cells correctly?


 What other way is there to place the cells? It's right against the bottom of each slot with button top against the lower two nipples and the inner silver contact pressing against the bottom of the cell.


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## HKJ (Jun 30, 2014)

18650 said:


> What other way is there to place the cells? It's right against the bottom of each slot with button top against the lower two nipples and the inner silver contact pressing against the bottom of the cell.



Try if you can press the front of the battery further down. On mine I can get contact without pressing fully down and then you do not need to touch the charger much to break connection to the battery.


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## jeffosborne (Jun 30, 2014)

AA cells get inserted top end first.
AAA cells go in bottom end first.

Jeff


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## SilverFox (Jun 30, 2014)

I had some connection issues with the AAA contacts so I took the unit apart and "adjusted" the contacts to eliminate the problem. After that I have had no problems unless the AAA cell has shrink wrap that wraps over the bottom radius of the cell.

My chargers are some of the first ones built. I don't know if this has changed with newer versions.

Tom


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## [email protected] (Jul 1, 2014)

*Question regarding Comparatisons and Raw Data Collected ?*

HKJ, 
Thank you very much for ALL your analysis work. I value it greatly because you execute it objectively and very analytically....kudos and thanks! 

*A. *After your review of the Lacrosse BC1000/1020 is published, I would be very interested in your *opinion* and the* pros/cons* comparing the *Maha C9000*, *LaCrosse BC1000/1020*, and the latest competitor *Opus BT-C2000 ver 2.1*. 

*Would you please provide one?*

*B.* I have performed a lot of data analysis using Excel and *would like to offer my services to our humble community*. If your testing equipment/software collects raw data and saves it I would be interested in using Excel to perform some comparative metrics. Sometimes comparative analysis leads to some rather interesting discussions that individual analysis may not. We never know unless we try. Just let me know sir.

Regards,
CS


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## [email protected] (Jul 7, 2014)

*Re: Question regarding Comparatisons and Raw Data Collected ?*

HKJ, 
Thank you very much for ALL your analysis work. I value it greatly because you execute it objectively and very analytically....kudos and thanks! 

*A.* I see your posted review of the La Cross BC-1020. Interesting they advertise improved performance with current LX processor but it looks like a bit of a failure especially when compared to offerings by competitors Maha and Opus.


*Offer still stands:
B.* I have performed a lot of data analysis using Excel and *would like to offer my services to our humble community*. If your testing equipment/software collects raw data and saves it I would be interested in using Excel to perform some comparative metrics. Sometimes comparative analysis leads to some rather interesting discussions that individual analysis may not. We never know unless we try. Just let me know sir.

Regards,
CS

[/QUOTE]


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## HKJ (Jul 7, 2014)

*Re: Question regarding Comparatisons and Raw Data Collected ?*



[email protected] said:


> *A.* I see your posted review of the La Cross BC-1020. Interesting they advertise improved performance with current LX processor but it looks like a bit of a failure especially when compared to offerings by competitors Maha and Opus.



I do not know if the new processor fails, but the software on the processor could be better on some points.


*


[email protected] said:



Offer still stands:

Click to expand...

*


[email protected] said:


> I have performed a lot of data analysis using Excel and *would like to offer my services to our humble community*. If your testing equipment/software collects raw data and saves it I would be interested in using Excel to perform some comparative metrics. Sometimes comparative analysis leads to some rather interesting discussions that individual analysis may not. We never know unless we try. Just let me know sir.



I do not believe that comparing raw data would be useful. What would be useful is a table comparing some of the metrics of the different chargers. This is stuff like, supported batteries, usb output, charge time for one battery, charge time for full load of batteries, charge algorithm, and a couple of other parameters.
My hope was to make it in a spreadsheet and then use my scripting to make it into a couple of web tables. My first try with this is the led driver table: http://lygte-info.dk/info/indexLedDrivers UK.html


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## WDG (Jul 7, 2014)

jeffosborne said:


> ...AAA cells go in bottom end first.




Somewhat depending upon when it was made. I use four of these units, bought in pairs, (in 2007, IIRC.) The older pair (0G0C01) prefer top end first, while the newer pair (0G0D01) work better bottom end in first, else the cells may pop out. 


There are a couple other differences that indicate that the "D" version was a fairly significant update. For example, the displays in the "D" version have much dimmer backlighting (following complaints of backlighting being too bright,) and they rate cells lower during BREAK-IN than the "C" versions (possibly more accurately.)


I have been extremely pleased with these chargers. My only wish is that they were all of the same version.




18650 said:


> ...I never used it to charge AAA cells (too many button presses req'd...




I assume you know that you can press & hold to change the charging, discharging, and other rates, instead of requiring individual button presses? It will continue stepping up or down until the button is released.


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## 18650 (Jul 7, 2014)

Yes I have been putting in cells bottom first and all the way in. I'd hate to have to open it to fix the faulty slots.


WDG said:


> I assume you know that you can press & hold to change the charging, discharging, and other rates, instead of requiring individual button presses? It will continue stepping up or down until the button is released.


 The alternative is to place cells into slots on my Sanyo charger and plug that into the wall. It charges at 400mA automatically. It's not worth the effort to use the C9000 for AAA for anything other than analysis.


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## Zef (Jul 7, 2014)

How long does a "refresh analyze" cycle take for a 2000mah AA eneloop? I'm time poor. Leaving on a trip in 30hrs and hoping to revive some old batteries. Also, at the end of a "refresh analyze" cycle are the batteries charged or do I need to do that as well?


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## HKJ (Jul 7, 2014)

Zef said:


> How long does a "refresh analyze" cycle take for a 2000mah AA eneloop? I'm time poor. Leaving on a trip in 30hrs and hoping to revive some old batteries. Also, at the end of a "refresh analyze" cycle are the batteries charged or do I need to do that as well?



If you look an the review above, you will see a curve that uses about 650 minutes, i.e. 11 hours:






The function will both charge before and after the discharge.


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## Viking (Jul 8, 2014)

Hi Zef

Refresh & analyze mode is a good way to sort the best batteries for your trip. However if you don't have the time to get through all your cells , you can use the ICV feature at startup ( It takes less than 15 seconds ) .
That funktion tells you how much internal resistance the individual cell has. The value is between 1.4-2.10. The higher the value the higher internal resistance.

You can also combine the two functions , by first do an initial ICV check for all the cells in stock to sort out the poorest. And then focus on the rest ( or best ) for the Refresh & analyze mode.

keep in mind ICV is only shown once at the display ( just before charging begins ). If the voltage value shown is below 1.4 it is not the ICV value , in that case just take the cell out and try again.

PS

All the cells should be in same state of charge before measuring and comparing ICV.


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## Zef (Jul 8, 2014)

Thank you very much for the detailed responses. I now have an accurate plan of attack. Cheers!


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## samgab (Oct 8, 2014)

Fantastic review as always, thanks HKJ. I missed this one when it first came out, but I'd been looking forward to seeing your test/review of this charger.
It seems, as I already knew, that this charger is very gentle on cells, keeping the temps nice and low when charging, and with its low max voltage termination followed by 2 hour trickle, it gently *almost* fills the cell, erring slightly on the side of undercharging rather than overcharging, which is what I'd prefer as it's kinder on the cells in the long term. The amount that it ends up undercharging is only a few mAh's, and doesn't really matter in the real life scheme of things, as anyone who is properly prepared carries at least one spare set when they have a mission critical need for the flashlight etc. And a few mAh's isn't going to make much difference to the single cycle runtime, but it can make a large difference to the long term longevity of the cells.


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## Turak (Oct 13, 2014)

whoops, sorry ignore


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## Tapis (Oct 20, 2014)

Thanks for the review. After reading all the positive comments about this charger, I have decided to buy it to replace the mediocre charger I use for my eneloops. I cannot order from Amazon. Does any of these CPFmarketplace dealers carry it? I checked a few and wasn't successful.


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## WDG (Oct 21, 2014)

I purchased mine from Thomas Distributing. I usually buy from them when I can, as I've always had great service from them. (It looks like they've got it on sale, right now.)


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## Tapis (Oct 21, 2014)

Thanks WDG, but shipping to East Europe (where I am presently) was a bit costly. Enerdan is Powerex distributor in Germany and their price and shipping rate are very reasonnable, so I ended up buying from them.


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## BillSWPA (Oct 23, 2014)

Thanks for the review. This thread coming up again is timely for me, since I am learning that merely recharging my cells might not be quite enough in all cases.


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## MidnightDistortions (Nov 2, 2014)

Great review . This charger is definitely a better analyzer than the LaCrosse one i have, but so far i have been able to use older NiMHs thanks to the LaCrosse charger. I plan to get a Powerex charger in the near future . The only problem that i read about this charger is the backlight won't shut off when in use don't know if that's still true or not.


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## StandardBattery (Nov 2, 2014)

I don't know if they have made any updates to this charger in a long time, but it's still a pretty good charger. I don't know why the light is a big issue for many. The Sky MC-3000 might come out next year sometime or the UltraSmart (w/LCD) might appear in the next few months that will probably set higher standards. The automatic data-logging to SD Card of the UltraSmart charger is pretty cool, and could create a nice history of cell performance over a long time period with regular use. The Opus BT-3100 and BT-2400 both seem like pretty good chargers although some here are reporting issues with their BT-3100 v2.1 chargers. I started testing mine more fully, and so far so good. Sounds like there might be quality control issues and depending on how you purchase returns could be a big hassle with long delays. The MH-9000 is proven and it's quirks are known. NiMh cells are pretty reasonable these days so just a basically good charger with proper process can go a long way and the right process with the not so good charger can be pretty effective also. The reviews can be very helpful in establishing a good process.


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## MidnightDistortions (Nov 2, 2014)

The backlight is a pretty good feature to have but it doesn't need to stay illuminated for very long unless you were staring at it during the time your charging/maintaining the batteries. It's difficult for some who sleep in the same room they have their charger in with the light staying on. Even then i am used to using a penlight when looking at the charger info.


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## Tapis (Nov 2, 2014)

@ MidnightDistortions - One can cut a small piece of cardboard and cover the screen. Problem solved.


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## Derek Dean (Nov 3, 2014)

Yes, Tapis, that's exactly what I've done (cut a small piece of cardboard to cover the lit panel), but it really would have been a nice touch to either have the screen go off after 20 seconds, or have a switch to turn it off manually. In any case, a minor issue for such a fine charger.


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## MidnightDistortions (Nov 3, 2014)

Yeah that's a good idea and it is a minor issue. The charger is still well designed.


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## racinjason (Nov 5, 2014)

I certainly like mine. Backlight isn't too bad. I've had mine for 2-3 years, never a problem.


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## racinjason (Nov 5, 2014)

It's a great charger. Never any problems.


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## SubLGT (Nov 27, 2014)

SilverFox said:


> I had some connection issues with the AAA contacts so I took the unit apart and "adjusted" the contacts to eliminate the problem. After that I have had no problems unless the AAA cell has shrink wrap that wraps over the bottom radius of the cell.
> 
> My chargers are some of the first ones built. I don't know if this has changed with newer versions.
> 
> Tom



I also had connection problems with AAA batteries from my early production C9000, and finally disassembled the charger and reshaped the negative contacts to contact the battery closer to the center of the battery base. I also bent the positive contacts for the AA batteries, because I was beginning to experience occasional problems with AA batteries not making full contact when they were inserted.


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## SubLGT (Nov 30, 2014)

Derek Dean said:


> Yes, Tapis, that's exactly what I've done (cut a small piece of cardboard to cover the lit panel), but it really would have been a nice touch to either have the screen go off after 20 seconds, or have a switch to turn it off manually. In any case, a minor issue for such a fine charger.



Cardboard? Tsk tsk.  I'm sure you could find something much more interesting in one of your Lee or Rosco filter swatch books.


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## Derek Dean (Dec 3, 2014)

SubLGT said:


> Cardboard? Tsk tsk.  I'm sure you could find something much more interesting in one of your Lee or Rosco filter swatch books.



Now why didn't I think of that? It turns out a LEE Filter Swatch fits perfectly over the LCD, and a deep blue one is actually quite lovely. Thanks for the suggestion, SubLGT!


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## mauricio (Dec 10, 2014)

Great review, thanks!!!:twothumbs


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## jonnyfgroove (Dec 10, 2014)

Viking said:


> However if you don't have the time to get through all your cells , you can use the ICV feature at startup ( It takes less than 15 seconds ) .
> That funktion tells you how much internal resistance the individual cell has. The value is between 1.4-2.10. The higher the value the higher internal resistance.



I've had this charger for years and I never realized it had this function.Thanks for the info.

And Thanks to HKJ for all his amazing reviews! :rock:


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## Grijon (Dec 23, 2014)

Excellent review, thank you HKJ! I have one of these on the way!


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## MidnightDistortions (Feb 3, 2015)

18650 said:


> Nice review.
> 
> Can you comment on the AAA charging slots?
> 
> ...





SilverFox said:


> I had some connection issues with the AAA contacts so I took the unit apart and "adjusted" the contacts to eliminate the problem. After that I have had no problems unless the AAA cell has shrink wrap that wraps over the bottom radius of the cell.
> 
> My chargers are some of the first ones built. I don't know if this has changed with newer versions.
> 
> Tom



I had this problem at first when i was testing my AAA Eneloop Pros. I remedied this by pushing the negative end on a slant holding that part of the battery in place while pressing down on the positive end. If you see the negative terminal pushed in and the little 2 indents in the middle of the positive terminal it should be in there correctly.

Now i seem to have the problem with some AAA batteries where the charger seems to detect the battery, start it's process and then reboots as if i took the cell out and put it back in again, what could be causing this? I know the battery is inserted correctly.


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## SilverFox (Feb 3, 2015)

Hello MidnightDistortions,

There are 2 main causes. One is that the cell is losing contact. The other is that the cell is crap.

Tom


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## MidnightDistortions (Feb 3, 2015)

SilverFox said:


> Hello MidnightDistortions,
> 
> There are 2 main causes. One is that the cell is losing contact. The other is that the cell is crap.
> 
> Tom



Thanks, pretty sure along with the cells being crap (though i think they need to be properly broken in) i also checked the length of them with another cell and they are slightly shorter. They'll only discharge properly at 100mA but take forever to charge at 200mA, so i was attempting to try break-in or cycle them a bit to see if they could be optimized. Guess i'll have to resort to using a dumb charger to see if they can be helped at all.


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## WDG (Feb 4, 2015)

MidnightDistortions said:


> ...Now i seem to have the problem with some AAA batteries where the charger seems to detect the battery, start it's process and then reboots as if i took the cell out and put it back in again...



I've seen this when the cell's internal resistance gets high enough. FWIW, at this point, my old C.Crane chargers usually reject them, also. I recycle them or use only on dumb-chargers, from then on.

BTW, AAAs usually seem to go first, in my experience. IIRC, they tend to already have higher internal resistance when new than AAs.


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## MidnightDistortions (Feb 4, 2015)

WDG said:


> I've seen this when the cell's internal resistance gets high enough. FWIW, at this point, my old C.Crane chargers usually reject them, also. I recycle them or use only on dumb-chargers, from then on.
> 
> BTW, AAAs usually seem to go first, in my experience. IIRC, they tend to already have higher internal resistance when new than AAs.



Hmmm, never noticed the difference between AA/AAA cell resistance. The only problem i have with these cells (some no name brand that was included in some walkies) is they haven't been used much. They seem to work fine in my keyboard and has normal HSD behavior but they don't seem to handle my AAA Minimag unless i leave the light running for a few minutes, they seem to start kicking in a bit better.. still a bit dim but bright enough to put out a couple of lumens. One thing that these smart chargers don't do is repeat discharge as these batteries have that phenomenon where if the batteries get too discharged, take off the load for an hour or so and they work again for awhile. But the key is to keep using the batteries or cycle them when needed. It's a good reason to date the last time the batteries were refreshed so you can do the process again even if they are not used.


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## L_D_Allan (Mar 11, 2015)

Thanks for the excellent review. I recall attempting to read it when I was considering the MH-C9000, but most of it was "over my head".

Now that I have had the charger for a month or so, I wonder if my model is newer than the one you reviewed. Perhaps it has newer firmware? I didn't observe if anyone else during this thread reported this. If so, my apologies.

*[EDIT] Wrong.*

*The reason I mention this is that the default for CHARGE is now 500 rather than 1000.* 

*[EDIT]: Wrong. My error. I had been using the C9000 to pre-discharge prior to BREAK-IN, related to another OP. I got the default DISCHARGE rate (500 ma) and default CHARGE rate (1000 mA0 mixed up.*

I am a CPF newbie, so perhaps the default is different for different batteries. That doesn't seem to be the case, because with every AA and every AAA I've put in the MH-C9000, it has wanted to use a default CHARGE of 500.

I don't know if other things have changed. Maha may have some kind of "change log". I wonder if there is a way to "flash" the firmware, like you can with many devices. That seems unlikely, as there isn't any provision for USB or flash card.

The MH-C9000 is part way thru a BREAK-IN, so I can't check the firmware version until later. Do you recall the firmware in your test device? Or is it in the review and I didn't notice it? Is the firmware version something that shows up when it powers up?


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## L_D_Allan (Mar 11, 2015)

L_D_Allan said:


> I don't know if other things have changed. Maha may have some kind of "change log".



I re-read the review, and did notice some other non-trivial differences

Internal resistance is reported ... there is an unexplained voltage not mentioned in their "user manual".
I asked about that in an early post of mine to CPF. IIRC, the reply was "internal resistance" (which this newbie doesn't comprehend)
http://www.candlepowerforums.com/vb...out-quot-mystery-voltage-quot-with-Maha-C9000
*[EDIT] I did find mention of HIGH mid-way in the review. Some or all of my comments in this post may not apply. Sorry.*
That voltage seems to only show up once for healthy batteries, near the start.
It may sometimes show up only for the first battery, sometimes for each battery.
I think the intended use might be to put one battery at a time in a slot, and observe what the internal resistance is, and proceed accordingly.
The value seems to be the basis for reporting HIGH as a very strong hint to try to Recover the battery and/or discard.
I had some old, abused AA's and AAA's. Their internal resistance would be well over 2.0 v. That value would show up, and then HIGH shown.
I was never able to RECOVER any of the batteries for which HIGH was reported. Perhaps someone with more battery experience could?
I ended up disposing of all those with HIGH. I've got a lot to learn to get the most out of my battery inventory.
The charger seemed to "freeze" if any of the batteries had a HIGH value.
IIRC, you couldn't even use the SLOT button to move to another battery with 2 or more were loaded.
I did a Google search on "maha MH-C9000 firmware" and got a number of "hits", but they weren't particularly current.
I used "Contact Us" to MahaEnergy.com with several questions.
latest firmware version?
change log?
update firmware possible for older chargers?
please confirm new feature of internal resistance and HIGH
also that default charge rate has changed from 1000 to 500
should have suggested that they update the user manual


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## Power Me Up (Mar 12, 2015)

L_D_Allan said:


> I wonder if there is a way to "flash" the firmware, like you can with many devices. That seems unlikely, as there isn't any provision for USB or flash card.
> 
> The MH-C9000 is part way thru a BREAK-IN, so I can't check the firmware version until later. Do you recall the firmware in your test device? Or is it in the review and I didn't notice it? Is the firmware version something that shows up when it powers up?



Unless they've changed the design, you can't update the firmware on the C9000 - last time I looked into it, Maha was using a one time programmable controller (i.e. once programmed, the firmware can't be changed)

If you take a look at the bottom of the charger, you should be able to find a sticker with a code on it - report back the code and that will give us an idea on how new it is.


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## HKJ (Mar 12, 2015)

L_D_Allan said:


> Internal resistance is reported ... there is an unexplained voltage not mentioned in their "user manual".





Resistance is in ohm, the voltage show is probably the voltage measured during the initial current pulse, this do give an idea about the internal resistance.


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## L_D_Allan (Mar 12, 2015)

Power Me Up said:


> If you take a look at the bottom of the charger, you should be able to find a sticker with a code on it - report back the code and that will give us an idea on how new it is.



ONODA ... is that different from what other owners have? Is it different from the review unit?


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## HKJ (Mar 12, 2015)

L_D_Allan said:


> ONODA ... is that different from what other owners have? Is it different from the review unit?



Yes, the review is OMOFA


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## MidnightDistortions (Mar 12, 2015)

L_D_Allan said:


> The value seems to be the basis for reporting HIGH as a very strong hint to try to Recover the battery and/or discard.
> I had some old, abused AA's and AAA's. Their internal resistance would be well over 2.0 v. That value would show up, and then HIGH shown.
> I was never able to RECOVER any of the batteries for which HIGH was reported. Perhaps someone with more battery experience could?
> I ended up disposing of all those with HIGH. I've got a lot to learn to get the most out of my battery inventory.





The only way you'll be able to try to recover a battery with HIGH (even though it's probably not possible to fix the High-IR cells, once they go High-IR they can't be helped) is to use a charger that will charge the cells even though the cells have already reached that point. Usually dumb chargers will do and you probably won't be able to use the cells in anything other than clocks, remotes and sometimes flashlights if the High-IR isn't too bad. You could always check how high the IR is by throwing them in the C9000 and checking the voltage. Higher the voltage reading the higher the IR is. Generally it's time to replace the batteries once the C9000 rejects the cells with HIGH, but some people like (me of course lol) to keep the cell and will charge it up in other devices that will charge the cell no matter what.


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## marcosg (Jul 13, 2015)

HJK, thanks for this great review. I have a question, at the bottom of your review you mention "
The charger is very good for analyzing batteries, but for normal charging the batteries might not always be filled".
This made me think. Even with the 2 hours top off applied by the charger the batteries should reach all the charge that the cells can get right?


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## HKJ (Jul 14, 2015)

marcosg said:


> "The charger is very good for analyzing batteries, but for normal charging the batteries might not always be filled".
> This made me think. Even with the 2 hours top off applied by the charger the batteries should reach all the charge that the cells can get right?



Usual they will be filled, but there is no guarantee.
Also remember that the top-off charge is applied after the charger reports done, i.e. you might believe that the charger is done and remove the batteries before they are topped off.


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## Tapis (Jul 16, 2015)

HKJ said:


> Also remember that the top-off charge is applied after the charger reports done, i.e. you might believe that the charger is done and remove the batteries before they are topped off.


 For how long is the top-off charge applied and when do we know that the max has been reached, that the charger is really done?


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## HKJ (Jul 16, 2015)

Tapis said:


> For how long is the top-off charge applied and when do we know that the max has been reached, that the charger is really done?



The top-off charge is two hours and the only way to know it is done is to start a stopwatch when the charger reports done.


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## Grijon (Jul 16, 2015)

What I do with mine is write down what time I started the charge. When the battery is shown as DONE the amount of time it took to charge is included as part of the information displayed; since I know when I started the charge and I know how long it was charging, I simply add 2 hours and take the batteries off more than 2 hours after being shown as done.

For example: Let's say I put my Durcell Ion Core cells in to charge at 2:30pm. At 5 pm I check and they show as done, so I wait for the Maha to display charge time. If the Maha shows 144 minutes then I know that the charger said DONE at 4:45pm and I can take the batteries out two hours after that (so that the two-hour top-off is finished) - so I'll come back after 6:45pm.

It requires me to write down when I started and then to do some math, but I'm OK with that. I hope this helps with any confusion.


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## WDG (Jul 22, 2015)

For the most part, I just leave the cells in overnight. No timing required, this way. With Eneloops, it's rare that I would need cells right away, anyway.


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## marcosg (Jul 22, 2015)

HKJ,
Do you remember any early termination on slot #1 using charging mode only at default of 1A while doing your tests?
all of my C9000's do that.
thanks


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## HKJ (Jul 22, 2015)

marcosg said:


> HKJ,
> Do you remember any early termination on slot #1 using charging mode only at default of 1A while doing your tests?
> all of my C9000's do that.



No, as you can see on my curves the slots looks fairly equal.


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## roadwarrior (Oct 3, 2015)

In researching this charger I downloaded the owner's manual and read through it. While there are detailed explanations for the modes, information was lacking for the "cycle" mode. 

Why would one use cycle mode? 

Thanks.


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## SilverFox (Oct 3, 2015)

Hello Roadwarrior,

Welcome to CPF.

When cells are stored for an extended period of time they sometimes can perform better if subjected to a number of charge/discharge cycles. The cycle mode allows the charger to do this for you.

Tom


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## roadwarrior (Oct 3, 2015)

SilverFox said:


> Hello Roadwarrior,
> 
> Welcome to CPF.
> 
> ...



Got it.

Thanks for feedback and the welcome! 

Been taking a hard look at the Maha MH C9000 and as of right now the only thing that has me not officially pulling the trigger is the fact that it dos not fully charge batteries after it displays DONE. Wish it had a DONE 2 another member suggested in another thread or some other option. I truly believe from what I have read and seen (on youtube) that it is a fine charger that is built well and of superior quality.....but I am at a lost of what to do.


Got two other chargers I am looking hard at too.....


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## MidnightDistortions (Oct 3, 2015)

roadwarrior said:


> Got it.
> 
> Thanks for feedback and the welcome!
> 
> ...



The C9000 will charge cells up to 90% and apply a 2 hour top off charge of 100mA, then it trickle charges at 10mA afterwards. The reason the charger does this is to extend the life of LSD NiMH cells such as Eneloops. The cells won't heat up much or at all near the end and you could pull them out and use them right away. You get more cycle life out of Eneloops with the C9000 which is why i primarily use it for all my LSD cells. If you use traditional cells, a charger like the La Crosse BC1000 is a good option, although the break-in functionality of the C9000 can help revitalize those cells better then the BC1000 could.


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## roadwarrior (Oct 3, 2015)

MidnightDistortions said:


> The C9000 will charge cells up to 90% and apply a 2 hour top off charge of 100mA, then it trickle charges at 10mA afterwards. The reason the charger does this is to extend the life of LSD NiMH cells such as Eneloops. The cells won't heat up much or at all near the end and you could pull them out and use them right away. You get more cycle life out of Eneloops with the C9000 which is why i primarily use it for all my LSD cells. If you use traditional cells, a charger like the La Crosse BC1000 is a good option, although the break-in functionality of the C9000 can help revitalize those cells better then the BC1000 could.



Thanks for the response. I have not had it explained in the manner you just did. Makes sense now. I like the fact the C9000 is set-up that way to prolong LSD cells. I plan on only using Eneloops 2100 cycle batteries in my application. So its good to finally hear the why on that 2 hour top off....

Would be nice if Maha in a future upgrade would account for this well thought out process it has by adding a "DONE 2" display reading after the 2 hour top off so one would know when it is completely done. Either way it is going to be Maha or Opus....starting to lean back towards Maha though. :thinking:


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## KeepingItLight (Oct 4, 2015)

MidnightDistortions said:


> The C9000 will charge cells up to 90% and apply a 2 hour top off charge of 100mA, then it trickle charges at 10mA afterwards. The reason the charger does this is to extend the life of LSD NiMH cells such as Eneloops.



I'm learning something here. I thought the *Maha MH-C9000* design dated back to before Eneloops, early 2000s or thereabouts.


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## SilverFox (Oct 4, 2015)

Hello Roadwarrior,

Fortunately the charger displays voltage for each slot. If you invest some time watching a charge you quickly realize that after the main charge the voltage will continue to climb during the top off charge. When the voltage drops back off the top off charge is done.

Tom


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## SilverFox (Oct 4, 2015)

Hello KeepingItLight,

I believe you are correct. It was rather forward thinking on Maha's part to engineer the charge algorithm this way. I believe they knew that LSD cells would be coming to the market soon and decided to modify the charge algorithm and trickle charge rate to be gentle on those cells.

Tom


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## roadwarrior (Oct 4, 2015)

SilverFox said:


> Hello Roadwarrior,
> 
> Fortunately the charger displays voltage for each slot. If you invest some time watching a charge you quickly realize that after the main charge the voltage will continue to climb during the top off charge. When the voltage drops back off the top off charge is done.
> 
> Tom



Thank you Tom! Getting close to pulling the trigger on it.


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## roadwarrior (Oct 4, 2015)

Anybody have any experience with Maha customer support?

In my opinion customer support is just as important as product quality.

Good or bad?

Thanks!


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## MidnightDistortions (Oct 4, 2015)

> Would be nice if Maha in a future upgrade would account for this well thought out process it has by adding a "DONE 2" display reading after the 2 hour top off so one would know when it is completely done.



It would make sense to have DONE flashing when the 2 hour top off is completed to let you know they are ready.


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## recDNA (Oct 4, 2015)

SilverFox said:


> Hello Roadwarrior,
> 
> Fortunately the charger displays voltage for each slot. If you invest some time watching a charge you quickly realize that after the main charge the voltage will continue to climb during the top off charge. When the voltage drops back off the top off charge is done.
> 
> Tom


That is very important and seldom mentioned. Thanks. I had no idea.


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## roadwarrior (Oct 5, 2015)

MidnightDistortions said:


> The C9000 will charge cells up to 90% and apply a 2 hour top off charge of 100mA, then it trickle charges at 10mA afterwards. The reason the charger does this is to extend the life of LSD NiMH cells such as Eneloops. The cells won't heat up much or at all near the end and you could pull them out and use them right away. You get more cycle life out of Eneloops with the C9000 which is why i primarily use it for all my LSD cells. If you use traditional cells, a charger like the La Crosse BC1000 is a good option, although the break-in functionality of the C9000 can help revitalize those cells better then the BC1000 could.



Just wanted to let MidnightDistortions and everyone else on here know that his statement is spot on.

Prior to getting the above reply from MidnightDistortions, I had e-mailed Maha support and asked why the C9000 will charge batteries to 90%, display "DONE" and then do a 2 hour top off charge, instead of just charging the batteries to 100%. 

The support representative's response was this:


"I don't know the exact percentage that the MH-C9000 charges up to but it does this to prevent overcharging of the cell." 

Which is right in line with what MidnightDistortions stated.

Many thanks MD!:thumbsup:


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## kreisl (Dec 20, 2015)

HKJ said:


> then it terminates on voltage


Is that voltage 1.47 or 1.48V? :devil:

Thanks!!


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## HKJ (Dec 20, 2015)

kreisl said:


> Is that voltage 1.47 or 1.48V? :devil:



You cannot simulate it on the MC3000, it cannot do the two hour top-off charge, except if you run two programs and accept that the second program stops with an error message and no battery information.


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## kreisl (Dec 20, 2015)

True, not exactly possible. So i am experimenting with the programs and tests anyway, as best as i can do.

I cannot read the voltage from the graph


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## kreisl (Feb 15, 2016)

HKJ said:


> [SIZE=+1]BREAK-IN: NiMH Slow cycle[/SIZE]
> 
> Break-in will first charge the battery for 16 hours with 0.1C, then discharge the battery with 0.2C (This will take about 5 hours) and finally charge again with 0.1C for 16 hours. The capacity of the battery is selected from 0.5Ah to 20Ah in 0.1Ah steps. When finished the display will show discharged capacity.
> This method over charges the battery, before measuring capacity, this means it will always get the highest possible value.
> ...



To which battery voltage (under load) does MH-C9000 discharge during Break_in right before the 60min resting pause? 
IEC demands 1.0V

Which exact voltage did you measure? Hard to tell from the resolved graph:


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## CanadaLight2 (Feb 18, 2016)

Can someone let me know what happens when you leave batteries on Discharge? I wanted to run some over night and they will finish sometime during the night. Is it bad to leave batteries on the C9000 for several hours after discharge reports "done"? I assume they continue discharging at the 0.8mA draw that happens on an inserted battery with no action, but I am not sure if this is at all damaging. Thanks!


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## ChrisGarrett (Feb 18, 2016)

CanadaLight2 said:


> Can someone let me know what happens when you leave batteries on Discharge? I wanted to run some over night and they will finish sometime during the night. Is it bad to leave batteries on the C9000 for several hours after discharge reports "done"? I assume they continue discharging at the 0.8mA draw that happens on an inserted battery with no action, but I am not sure if this is at all damaging. Thanks!



I think DONE only comes up after charge and then we leave them on the Maha C9000 for 2 hours, which completes the charging process.

After you discharge down a battery to .90v, it should bounce back a bit and leaving it on the charger for a few extra hours shouldn't hurt things. Now, leaving them at .90v for a year, well, you might not want to do that.

Chris


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## kreisl (Feb 28, 2016)

"top-off charge is 100mA, trickle charge is 10mA" .. Does this identically apply no matter which battery is inserted, AA (2500mAh) or AAA (600mAh) ?


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## HKJ (Feb 28, 2016)

kreisl said:


> "top-off charge is 100mA, trickle charge is 10mA" .. Does this identically apply no matter which battery is inserted, AA (2500mAh) or AAA (600mAh) ?



Charger do not know what battery is in it, it used the same each time.


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## TinderBox (UK) (Feb 28, 2016)

I would like another C9000 after my last one died, but spending £50 on an nihm only charger when i can get an BT-C3100 for £25 and it does nihm and li-ion.

John.


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## ChrisGarrett (Feb 28, 2016)

TinderBox (UK) said:


> I would like another C9000 after my last one died, but spending £50 on an nihm only charger when i can get an BT-C3100 for £25 and it does nihm and li-ion.
> 
> John.



John, yeah...when you look at it that way, it probably doesn't make sense. I spent about the same, in not a bit more on my LaCrosse BC-700, than I did on my C9000 at the same time and I wouldn't do it again.

Still, the Maha is an excellent NiMH charger with a long track record.

Starting anew, the SkyRC MC3000 might be the most cost effective way to go if one is smart enough and likes to utilize all of its features.

I'm neither.

Chris


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## kreisl (Feb 28, 2016)

HKJ said:


> Charger do not know what battery is in it, it used the same each time.



Thanks for the confirmation of information! :thumbsup:


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## johnc847 (Mar 5, 2016)

Put these new 2400 mah batteries on break in cycle last night. I set each battery to 2400 mah when starting it. This morning they're showing on charge and they're all showing in the ~3300 mah range. Is something wrong with the batteries or charger? Do I just let it keep doing its thing?






*Edit:*

It finally started resting 12 mins ago. The mah on all 4 is ~3440. These are 2440 batteries and I made sure to enter that when starting the Break-In mode. Pics are below showing the mah put into them during the charge cycle. 

I'm still new to the terms but the below are the 2 possible reasons I can think of. My terms you'll notice what I put in quotes below. 

1- Did the charger just miss the "whatever it's called" that they were fully charged and kept charging till it caught it at around ~3440?

2- Could the batteries have been made to hold a lot more than rated by mistake and actually have a capacity around ~3440?

With the above said, is the only way to know the true capacity of these to wait to see the mah after the final charge after it discharges the batteries? Or would it be the mah on the discharge it will run after resting? 

If it's on the discharge, and the discharge shows ~2400 mah, and the 2nd charge puts out ~3440 math again, does that mean these batteries are bad or that the charger is starting to have issues?

Slot 1:





Slot 2





Slot 3:





Slot 4:


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## ChrisGarrett (Mar 5, 2016)

You need to wait until the break-in period is over. The B.I. function slowly overcharges the batteries over a 16 hour charge cycle at .1C per hour, IIRC. Once the B.I. is complete, you will see the final charged capacity as displayed and it will be lower.

Freaked me out the first time, as well!

Chris


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## SilverFox (Mar 5, 2016)

Hello Johnc847,

The Break In function is designed to do a timed charge for 16 hours and charge roughly at a rate of 0.1C. If you put 2400 mAh at the start, the charge rate will be around 240 mA. If the charger was a constant current charger it would put 240 X 16 = 3840 mAh INTO the cell. Since it pulses you only get about 90% of that, so I would expect to see 3456 mAh.

It looks like the math and reality are reasonably close...

Keep in mind that the amount put in does not equal the amount you can use. You need to do a discharge to determine that amount.

Tom


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## johnc847 (Mar 5, 2016)

SilverFox said:


> Hello Johnc847,
> 
> The Break In function is designed to do a timed charge for 16 hours and charge roughly at a rate of 0.1C. If you put 2400 mAh at the start, the charge rate will be around 240 mA. If the charger was a constant current charger it would put 240 X 16 = 3840 mAh INTO the cell. Since it pulses you only get about 90% of that, so I would expect to see 3456 mAh.
> 
> ...



Ok thank you very much! I was worried the batteries were defective and would leak or the charger was going bad or something. Glad everything is good. Thank you again!


----------



## TinderBox (UK) (Mar 6, 2016)

So what were the capacity results for you 2400mah AA ??, it looks like they were Amazon Basics from the photo, they have an 2500mah AA version now, Amazon seems to sell a lot of their own branded battery now, though they seem expensive in the UK, you can buy Eneloops at those prices.

£8.99/$12.80 for 4 x AA 2000mah Amazon Basics is expensive, I can get Lidl 4xAA 2300mah for £2.99

http://www.amazon.co.uk/gp/search/r...1411031&bbn=6623637031&ie=UTF8&qid=1457261602

John.


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## johnc847 (Mar 6, 2016)

TinderBox (UK) said:


> So what were the capacity results for you 2400mah AA ??, it looks like they were Amazon Basics from the photo, they have an 2500mah AA version now, Amazon seems to sell a lot of their own branded battery now, though they seem expensive in the UK, you can buy Eneloops at those prices.
> 
> £8.99/$12.80 for 4 x AA 2000mah Amazon Basics is expensive, I can get Lidl 4xAA 2300mah for £2.99
> 
> ...



The label says 2400 mah. The discharge finished overnight and it's now in charge. I'm still getting used to this charger. Is the only way to see the actual capacity after a discharge cycle completes? If so is there anyway to see what that was since it's now in charge, or would I need to run just a discharge cycle alone after this break-in completes?

That's weird you can get 2500 mah. I don't see those as an option. The highest mah I see is 2400 and have been buying those in an 8 pack for $19.99. 

AmazonBasics AA High-Capacity Rechargeable Batteries (8-Pack) Pre-charged https://www.amazon.com/dp/B00HZV9WTM/?tag=cpf0b6-20

I googled Lidl and are you talking about Tronic batteries? If so are they good? I mainly use my rechargeable AA's in my scanner all day so I like batteries that last a long time per charge and that will last many charges. 

Do you think I should stop buying these Amazon and switch to something else? If so what do you recommend? Eneloop with around 2400 mah are pretty expensive here. A 4 pack of 2550 mah are $16.75.

Panasonic BK-3HCCA4BA Eneloop Pro AA High Capacity Ni-MH Pre-Charged Rechargeable Batteries (Pack of 4) https://www.amazon.com/dp/B00JHKSL28/?tag=cpf0b6-20


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## TinderBox (UK) (Mar 6, 2016)

CPF has a few threads on Tronic Lidl battery just do a search and they get good result, I just finished a capacity test using my BT-C3100 on 8x Tronic Energy Eco 2300mah and i got and average of 2250-2280mah and that`s not bad for £2.99 a pack 4 battery`s

Yeah, I double checked Amazon 2500mah see photo below.

Panasonic Pro AA or also know as Eneloop XX are only 500 cycle and they have been tested as low as 300 cycles if you run them flat every time.

John.


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## johnc847 (Mar 6, 2016)

TinderBox (UK) said:


> CPF has a few threads on Tronic Lidl battery just do a search and they get good result, I just finished a capacity test using my BT-C3100 on 8x Tronic Energy Eco 2300mah and i got and average of 2250-2280mah and that`s not bad for £2.99 a pack 4 battery`s
> 
> Yeah, I double checked Amazon 2500mah see photo below.
> 
> ...



Yeah I believe you. When I clicked your link to the post earlier it took me to them but on the Amazon UK site. Just don't know why they're not on us site. I'll have to get some of those Tronic batteries to try out. That's a great price. Thanks for the heads up on them. Do you happen to know how many cycles they get?


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## TinderBox (UK) (Mar 7, 2016)

The packaging on the Tronic Energy Eco AA 2300mah say they are good for up to 1000 cycles.

John.


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## CLHC (May 28, 2016)

Well, I'm no Techie but I went ahead and ordered this specific Battery Analyzer Charger Tester. Looking forward to it. Thanks for the extensive review(s)!


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## MidnightDistortions (May 29, 2016)

Batteries and Bulbs are selling the C9000 for $29. At least at the local store, online it's more than what it is on Amazon.com.


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## TinderBox (UK) (May 29, 2016)

That`s a nice price $29, In the UK they sell for £47 that`s $68 and is a rip off for a 10 year old charger, The c9000 is still a nice charger for NiMh.

John.



MidnightDistortions said:


> Batteries and Bulbs are selling the C9000 for $29. At least at the local store, online it's more than what it is on Amazon.com.


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## TinderBox (UK) (Jan 1, 2017)

Hi Henrik

I was reading in the older C9000 threads that the maximum battery capacity had been reduced from 20.000mah to 4.000mah so that if the termination is missed the battery`s don't get overcharged.

If this change has occurred i will not be happy as i want to charge some 5.000mah C battery`s and D cells up to 10.000mah using my D and C cell adaptors.

Thanks

John.


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## SilverFox (Jan 1, 2017)

Hello John,

I believe all current C9000 units have the 4000 mAh limit. This makes sense for AA cells, and is a little high for AAA cells.

When you go to C and D cells you need to charge in stages. 

Note that this limit doesn't apply to discharge but the upper limit for BreakIn is 9900 mAh.

Tom


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## TinderBox (UK) (Jan 1, 2017)

SilverFox said:


> Hello John,
> 
> I believe all current C9000 units have the 4000 mAh limit. This makes sense for AA cells, and is a little high for AAA cells.
> 
> ...



The Maha website and the downloaded manual says it supports up to 20.000mah

http://www.mahaenergy.com/mh-c9000/

John.


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## SilverFox (Jan 1, 2017)

Hello John,

You are going to have to test it out. I wasn't aware that they changed back to the original set up.

Tom


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## TinderBox (UK) (Jan 2, 2017)

Hi.

Can dropping an nimh battery on the floor kill it`s charge, I have a new pack of Fujitsu AAA 900mah LSD, I dropped one on the floor while i was getting them out of the packet, then i put them in my Opus C3100 and did a quick test (resistance) and i got a result of approx 80 for all 4 battery`s

Then i did a discharge at 200ma, one cell only gave 25mah and the other 3 gave between 210-237mah.

Any ideas ??

Thanks

John.


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## kreisl (Jan 2, 2017)

am not sure if it has been studied before.

never mind.

how about a full test in C3100 of all 4 batteries?


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## TinderBox (UK) (Jan 4, 2017)

SilverFox said:


> Hello John,
> 
> You are going to have to test it out. I wasn't aware that they changed back to the original set up.
> 
> Tom



I bought an C9000 and the 4000mah charging limit is still there 

John.


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## TinderBox (UK) (Feb 7, 2017)

Is there no "reverse polarity protection" on this charger as some have reported, I did have an channel die on one of my C9000, It would discharge but not charge, I wonder if this was the cause.

John.


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## HKJ (Feb 7, 2017)

TinderBox (UK) said:


> Is there no "reverse polarity protection" on this charger as some have reported, I did have an channel die on one of my C9000, It would discharge but not charge, I wonder if this was the cause.
> 
> John.



I do not know it. On many NiMH chargers the slot is made a way that makes it difficult or impossible to reverses the cells.


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## TinderBox (UK) (Feb 7, 2017)

HKJ said:


> I do not know it. On many NiMH chargers the slot is made a way that makes it difficult or impossible to reverses the cells.



I saw a photo of an C9000 with burnt contacts the owner said he had pu the battery in backwards

See photo`s from review on Amazon.

https://www.amazon.com/Powerex-MH-C...Analyzer-Batteries/product-reviews/B003DIGKOG

John.


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## kreisl (Feb 7, 2017)

amazon customer said:


> I called Maha to find out why the charger did not prevent this from happening. The tech support department told me that there is NO REVERSE POLARITY DETECTION. I was floored. How can a product like a battery charger that can output almost 2 amps NOT have reverse polarity detection?


John, i would not believe everything what's found posted on the internet, especially not customer reviews, and especially not on amazonDOTcom. I have a C9k too and it works just fine.

And the fact that i canot remember having put in batteries in opposite direction does not necessarily mean that the charger does not have reverse polarity protection. I would not see the sense in that kind of logic.

It is hard to believe that this best of the best NiMH charger does not have reverse polarity protection. Maha is a 100% Taiwan company (sure, with EU and US distributions) and i shot them an email but i never got any response. I resent the email, still no reply. 

Since then, i resent them pun intended.


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## timidhermit (May 16, 2018)

I own a number of the Powerex MH-C9000 over the years.

I am trying to discover the manufacturing dates of these chargers so to document them (along with the firmware dates) for my own records.

I read on this forum that the production date or manufacturing date of the chargers can be deduced from the 5-digit alphanumeric code on the warranty label on the back of these devices.

I tried my best to search on this forum but cannot find a guide on how to read the code to determine the month (or cycle) and year when a charger was manufactured.

Can someone point me to the right post or thread to get this info?


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