# Test/Review of Charger Xtar VC4



## HKJ (Apr 10, 2015)

[size=+3]Charger Xtar VC4[/size]















Xtar makes many LiIon chargers, this is a usb powered quad channel charger with display. The charger can charge with up to 1A for two channels or 0.5A for four channels, actual current depends on slots used and available usb power. It supports both NiMH and LiIon cells.



 

 

 

 

I got the charger in a cardboard box with the specifications printed on it.






Inside the box is a fabric bag with the charger in, this can be useful for traveling and to keep the manual, charger and cable together.






The bag contained the charger, a cable (charger to usb), a warranty card and a instruction manual.






The charger is usb powered, but the connector is a DC barrel connector, i.e. you need the supplied cable to connect the charger. I would have preferred the ability to use a normal usb cable. The DC barrel connector is not compatible with the one used on the 12V chargers, i.e. there is no risk of connecting a 12V power supply from another Xtar charger to this charger (Very good).
Another way to handle this would have been to make the charger accept both 5V and 12V power.

I got no USB power supply with the charger (Xtar say that they will also be selling a compatible usb power supply). I have tested some usb power supplies and it is possible to find a useable one on my list (Remember it must supply at least 2A for full charge speed).






There is a display, four red/green leds and one button. The button has a couple of functions:
1) Restore full background light on the display (The light will dim after a short time).
2) Turn the background light/display off or on, a long press will turn it off, any press will turn it on again.
3) Select what slots are displayed, this is only necessary if more than two batteries a charged simultaneous.
The leds are red while charging and green at all other times. This makes it very easy to see when a slot is finished.






The display uses dials to show voltage and maximum current, it does also have some 7 segment digits to show charged capacity and slot number.






The current dial only shows the maximum charge current, the actual current is lower when the battery is in the CV phase.
The voltage dials shows the actual voltage when in range:
0V Battery voltage is low, charger is only using low current, display may show "Err" if there is a problem with the batteries.
3.0V Voltage is high enough to start regular charge.
3.5V-4.2V Regular charge, display is within 0.1 volt.
If the charger only has two batteries in it, the display will always show them, independent of slots used, with 3 or 4 batteries the switch must be used to select between them.









The charger can handle both button top and flat top batteries.
The slider moves smoothly and can hand cells from 30mm to 71 mm long.
















































The charger can handle 71 mm long batteries, including flat top cells.



[size=+2]Measurements charger[/size]



When charging the last digit in the capacity displays will flash.
The charger will charge with 100mA from 0 volt and display will show NiMH
Charger will not stop NiMH charging within the first 10 minutes.
Above 2.0 volt the charger assumes LiIon battery.
Between 2.0 volt and 2.9 volt charge current is 120mA on 1A range.
Above 2.9 volt the full charge current will be applied.
When charge is finished the charger will charge with 0.2mA.
The charger steps charge current down when the usb voltage at the charger is below 4.7 volt.
Charger will restart if voltage drops to 3.9 volt.
Charge will restart charging after power loss, or battery insertion.
When not connected to power it will drain about 0.6mA from a LiIon and 0.2mA from a NiMH battery.
Current dial will show maximum possible charge current, not actual charge current.
Voltage dial will show within 0.1 volt when voltage is in range.
The 3 volt position on the voltage dial looks like it signals "start of regular charge", i.e. 2.9 volt.
mAh display flashes "Full" when the corresponding battery is full.
With only slot #1 and #4 in use maximum charger current is 1A
With slot #2 or #3 in use all slots are limited to 0.5A charge current.

The light green line is usb current consumption, the dark green is charge current.

[size=+1]Charging LiIon[/size]






The charger does a nice CC/CV charge with a termination at about 70mA. The changing DC input current shows that this charger is using a switching charge regulator.
The display shows 2807mAh charged into the battery.














The other channels has a similar result. Slot #2 and #3 is charging with 0.5A. The termination current is the same on all slot at around 70mA
The display shows 2791mAh, 2776mAh and 2784mAh charged into the battery.






The 2600mAh battery has a long CV phase, probably because it is getting old.
The display shows 2172mAh charged into the battery.






The 3400mAh takes slightly longer to charge.
The display shows 3047mAh charged into the battery.






The charger has no problem with my old IMR cell, but there is not much capacity left in it.
The display shows 154mAh charged into the battery.






The 18350 cell is better, I uses slot #2 to limit the charger current to 0.5A
The display shows 695mAh charged into the battery.






The 14500 is also charged in slot #2
The display shows 754mAh charged into the battery.






Charging 4 LiIon cells at the same time is a rather slow, because the charger turns the charge current way down with my power supply and wires.
The display shows 2407mAh 2498mAh 2566mAh 2518mAh.






Increasing the usb voltage to 5.2V to compensate for wire losses improves the charge speed.
The display shows 2781mAh 2764mAh 2884mAh 2857mAh.






Supplying a falling voltage to the charger shows that the current regulation starts reducing the charge current rather soon, this is due to resistance in the cable and connection.






M1: 28,6°C, M2: 30,9°C, M3: 30,6°C, M4: 29,1°C, M5: 31,1°C, HS1: 37,1°C
The charger does not heat the batteries much during charge.
To do these photos I uses this usb power supply, it maintains the output voltage slightly above 5 volt, this allowed the charger to use full charge current.






M1: 28,2°C, M2: 30,0°C, M3: 30,0°C, M4: 28,1°C, HS1: 35,2°C
As usual the power connector get warm, but here the heat is very limited.






The charger needs about 10 seconds to start.






The 1A current is steady, no pulsing is used.






The 0.5A charge current is a reduction of charge current, not pwm regulation.



[size=+1]Charging NiMH[/size]






The charger was a bit doubtful about my 5 volt power supply and did reduce the charge current a couple of times.
The charging terminates on voltage and then does a top-off charge, as can be seen in some of the other curves this top-off takes about 2 hours. It is done after the charger reports done.
Display shows 1605mAh










The two 0.5A channels works the same way.
Display shows 1627mAh 1673mAh






The last channel accepts my power supply and uses full charge current all the time. On most of these charts it looks like the temperature is starting to raise, just before the charger terminates, this means the battery is fully charged.
Display shows 1661mAh














With these batteries the temperature raise is obvious.
Display shows 1750mAh 2312mAh 2209mAh






Here I am missing the temperature raise, i.e. the termination is a bit premature.










The charger can detect a full cell within a few minutes when it starts charging, but because the 10 minutes precharge it takes some time to detect the full cells.






With 4 cell the charger cannot get enough power from my 5 volt supply (due to cable and connection resistance), it need a bit more volt for full charge current.
Display shows 1676mAh 1683mAh 1746mAh 1720mAh






Raising the voltage a bit gets the charger up to full speed.
Display shows 18526mAh 1919mAh 1858mAh 1834mAh






Adding an extra 0.5ohm resistor in series with the power supply did not work, the charger needs a better power supply than that.






M1: 29,9°C, M2: 31,4°C, M3: 31,3°C, M4: 29,6°C, M5: 32,3°C, HS1: 38,7°C
Also NiMH cells stays very cool during charge.






For NiMH it takes 8 second from power on to precharge is started.






The precharge runs for 10 minutes, before regular charger kicks in.






Precharge is about 120mA with pulsing each second.






1A charging has the same pulsing and uses 1A as charge current in the pulses, average charge current will be a bit lower due to the pulsing.






0.5A charging reduces the current, there is no pwm regulation.






The two hour top-off charge is done with pulses.






And the current depends on the charge current.



[size=+1]Charging LiIon and NiMH[/size]

Mixing LiIon and NiMH cells in the charger is no problem.






In the above curve I measure on the NiMH cell (Except temperature that is on a LiIon), the NiMH finished first.






In this curve the NiMH finished first (the DC input current drops) and I continue recording the LiIon data.


Because the charger is supplied from usb power there will not be any safety issues with it, but be careful with the usb power adapter.



[size=+2]Conclusion[/size]

The charger is very good at both LiIon and NiMH charging and keeps some impressive low cell temperature during charge (Like the VC2).
For charging at full current the charger is fairly demanding of the used usb power supply. It is possible to use weaker supplies, but the charging will be slower or sometimes much slower. With the current dial it is easy enough to see when that happens and it is time to get a better usb power supply. I would have liked slightly better performance with weak usb power supplies.

This type of charger is what I will call a family charger. Nearly anybody in the family can use it, just put the batteries into the charger and wait. Only caveat is that small batteries go into the two centre slots or, for sets of four, in all four slots.

Final conclusion must be that it is a good charger.



[size=+3]Notes[/size]

The charger was supplied by XTAR for a review.

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


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## KITROBASKIN (Apr 10, 2015)

staggering thoroughness


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## thedoc007 (Apr 10, 2015)

As always, thanks for the review. 

I'm a little mystified...a USB-powered charger that doesn't use a standard USB cable/connector is an odd choice. Especially when performance is seriously degraded without a high-powered and voltage-controlled source. Am I missing something? Why is this a good idea?


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## HKJ (Apr 10, 2015)

thedoc007 said:


> As always, thanks for the review.
> 
> I'm a little mystified...a USB-powered charger that doesn't use a standard USB cable/connector is an odd choice. Especially when performance is seriously degraded without a high-powered and voltage-controlled source. Am I missing something? Why is this a good idea?



My guess is that this way Xtar can be sure you are using a good cable between the charger and the usb power supply and not a cheap *thin* usb cable.


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## Ferdinando (Apr 10, 2015)

very good rev HKJ
It is confirmed that this charger require a 'strong' USB power-source for doing the best work.


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## Mr. Tone (Apr 10, 2015)

Great review, the new display is pretty cool looking.


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## lumen aeternum (Apr 11, 2015)

With only slot #1 and #4 in use maximum charger current is 1A
With slot #2 or #3 in use all slots are limited to 0.5A charge current.

Is that something you discovered, or is it stated in the manual & marked on the charger? Seems odd that using ONLY the center slots limits the current.


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## HKJ (Apr 11, 2015)

lumen aeternum said:


> With only slot #1 and #4 in use maximum charger current is 1A
> With slot #2 or #3 in use all slots are limited to 0.5A charge current.
> 
> Is that something you discovered, or is it stated in the manual & marked on the charger? Seems odd that using ONLY the center slots limits the current.



It is marked on the charger, stated in the manual and shows up in my test (It is not the first Xtar charger that works this way).
Look closely at the bottom of on this picture:


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## hammerjoe (Apr 11, 2015)

HKJ,

Thanks for the review, very nice and informative as usual.

Now as far as NIMH is concerned which one does a better a job charging them?
This Xtar or the Opus 3100?

Or it doesnt matter they are both as good as it gets?


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## HKJ (Apr 11, 2015)

hammerjoe said:


> Now as far as NIMH is concerned which one does a better a job charging them?
> This Xtar or the Opus 3100?
> 
> Or it doesnt matter they are both as good as it gets?



Mostly they are the same, but I would expect the Opus to be slightly better at getting all batteries full and the Xtar may be slightly better with old batteries.


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## SubLGT (Apr 11, 2015)

deleted


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## HKJ (Apr 11, 2015)

SubLGT said:


> Is there a technical challenge that is stopping Xtar from manufacturing a 4 channel charger that can charge at 1A in all 4 channels simultaneously ?



You cannot do it on usb power, but with a 12V charger it is easy enough to do, but heat is difficult to manage.
When you check my reviews of compact 4 channel chargers they are always rather warm when charging or has a fan.


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## SubLGT (Apr 11, 2015)

HKJ, you are quick! I deleted my question after seeing that Xtar does indeed manufacture a 4 channel charger that can charge at 4 x 1A. The XP4 Panzer.

You reviewed it a few years ago: http://www.candlepowerforums.com/vb...w-of-Charger-Xtar-XP4&highlight=test+xtar+xp4



"The charger gets hot while working at maximum current, the battery temperature is just at the allowable limit. I would have preferred both the box and the batteries where considerable cooler, this heat does wear the batteries down faster………….."


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## HKJ (Apr 11, 2015)

SubLGT said:


> HKJ, you are quick!



When I am working at the computer I will often answer immediately.


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## Aperture (Apr 12, 2015)

thedoc007 said:


> I'm a little mystified...a USB-powered charger that doesn't use a standard USB cable/connector is an odd choice. Especially when performance is seriously degraded without a high-powered and voltage-controlled source. Am I missing something? Why is this a good idea?


Because micro USB is limited to 1.8A and this charger needs more than that to run at full power.

The logical step would be the DC 5.5x2.1mm plug but they already use that size for their 12V adapters, so for safety reasons Xtar went with the 5.5x2.5mm plug, both are very common plug sizes with a plethora of adapters, extension cables, chargers, etc out there on eBay.


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## ven (Apr 12, 2015)

As always your time and effort in your fastidious reviews are highly appreciated HKJ:thumbsup:

This charger will soon be a "works" charger,2 reasons other than its Xtar and good,1- i dont need more than 2 x18650 at a time charged in work(sr51 as one example) 2- It is good at NiMH ,so my e25 burst 2xAA and T7.2 2xAAA all eneloops fed will be very happy

I await a vc6 which "may" give an option of 4 of the 6 bays a 1a charge rate..........that i would buy for home use(of course i would prefer 6x1a rate,but realistic due to heat and size). I just want a good charger that can handle 4x1a rates and by Xtar.

Thanks ven


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## Berneck1 (Apr 12, 2015)

I have this charger and like it for what it is. However, I felt a little mislead by the USB power. I thought I would be able to travel with less cables, but alas I HAVE to bring this extra cable along. Almost making the fact that it is USB pointless. 

On the other hand, it is a good point, the lower input does make it a little more idiot proof.




Sent from my iPad using Candlepowerforums


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## HKJ (Apr 12, 2015)

Berneck1 said:


> However, I felt a little mislead by the USB power. I thought I would be able to travel with less cables, but alas I HAVE to bring this extra cable along. Almost making the fact that it is USB pointless.



But you might be able to travel with a power supply less, that is considerable larger than a usb cable.


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## Berneck1 (Apr 12, 2015)

HKJ said:


> But you might be able to travel with a power supply less, that is considerable larger than a usb cable.



True, every little bit helps I guess...


Sent from my iPad using Candlepowerforums


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## StorminMatt (Apr 12, 2015)

Berneck1 said:


> I have this charger and like it for what it is. However, I felt a little mislead by the USB power. I thought I would be able to travel with less cables, but alas I HAVE to bring this extra cable along. Almost making the fact that it is USB pointless.



Not really. The fact that it is USB also makes it easily usable with such things as USB solar panels and USB car chargers.


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## johndoe1027 (Apr 12, 2015)

Thank you for another fantastic review HKJ! I have the XTAR VP1 now (which I only bought after seeing that you gave it a thumbs up). I've since got into vaping and have tossed around the idea of getting some 26650s (which the VP1 doesn't do). Also, more charging slots = better. 

2 things I love about the VP1 that I don't want to lose. 
1 - 0.25A charging capability. Can you tell the VC4 to stay at 0.25A max?
2 - Voltage readout to the hundredth of a volt. It looks like the VC4 never shows a numeric voltage readout, is that correct? It's just on the gauge. My only reason for wanting a precise voltage readout is 2 pairs of batteries that I have married for series use. I guess having the mAh readout is as good or better for seeing how close 2 batteries are in performance?

Maybe I am really looking for a VP4 instead of the VC4? Thanks in advance for any advice you have!


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## RI Chevy (Apr 12, 2015)

VP 4 already out I think.


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## ven (Apr 13, 2015)

One on its way  will be my 4th Xtar charger and with good reason. Will be a works charger ,need one for 18650 and eneloops in one.


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## candle lamp (Apr 14, 2015)

Thank you for your excellent review. HKJ! :thumbsup:
It seems that the VC4 has feature of the VP4 plus Ni-MH charging.


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## ven (Apr 17, 2015)

VC4 came today to add to my xtar chargers,initial impressions are great,love the carry bag............great idea,even if used to protect/cover/store as well as obviously travel. 
Display is nice and bright,simple button press to change ch1+4 or ch 2+3 read out. Think i would prefer all to be shown but (or fitted in display) tbh ,but no deal killer. Certainly a nice solid/substantial feel to the plastic over some chargers like the i4 and wp6II.

Gripe,yes one that bothers me a little,i would have preferred the actual plug to be universal when fitted in charger port(not usb end thats a great idea) plug end........ Maybe an actual Xtar USB plug thrown in..........just a thought and i may be alone on that :laughing: I have lots of USB plugs,would just prefer to use an Xtar branded one over say an apple or alike.........

Yes working hands (they do get washed honest)........... dry skin and being an engineer=

Plug differences with vp1 charger




As i will not be using it direct into say laptop(usb is great for flexibility ,so dont get me wrong here) i would have liked it to be universal,so use of the vp1 or vp2 chargers leads as examples.......again personal gripe and i know its designed around travel/usb use..........just would have been nice for it to work off Xtar adapters for added flexibility(or again throw in a usb plug)

Norb sent me a couple of free 14500 cells,dont know if good........will check up :laughing: but grateful all the same












Its kind of in the middle right now...........








My decider on this charger thanks to HKJ,was the Ni-MH support,will be great in work for my eneloops:thumbsup: and my 18650 cells of course.

Sure the display will "grow" on me,just prefer actual digital V read out (4.16 for example) over a needle/gauge........just user friendlier imo anyway. Something i no doubt will get used to over time. The mah will be useful,but again,will show from where the V is to start from,most my cells are 3.8v in lights,ecig mods...........well some 3.6v,.the vaporshark rDNA40 will run to 3.3v so that should give a better indication to the cells mah(IMR and INR only for those uses).

Time will tell and admit Xtar is my fav brand of chargers,this certainly has a "quality" feel to it,thanks again HKJ:thumbsup:

Cheers ven


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## HKJ (Apr 17, 2015)

ven said:


> Gripe,yes one that bothers me a little,i would have preferred the actual plug to be universal when fitted in charger port(not usb end thats a great idea) plug end........ Maybe an actual Xtar USB plug thrown in..........just a thought and i may be alone on that :laughing: I have lots of USB plugs,would just prefer to use an Xtar branded one over say an apple or alike.........



The problem is that a 12V power supply probably will blow the VC4, i.e. I see it as an advantage that it uses a different plug.
I would have liked it even better if it could work on both 5V and 12V, then there would be no problem with using the same plug as other Xtar chargers.


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## ven (Apr 17, 2015)

Quick question just to make sure(i have already done it issue free but want to know long term) Am i OK using an apple USB plug or any other specific plug over this for plugging in the wall(or am i best not to plug into the wall via USB).

Many thanks ven


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## HKJ (Apr 17, 2015)

ven said:


> Quick question just to make sure(i have already done it issue free but want to know long term) Am i OK using an apple USB plug or any other specific plug over this for plugging in the wall(or am i best not to plug into the wall via USB).



I suppose you mean using a Apple usb power supply and that is fine, the problem is all the cheap Chinese ones.


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## ven (Apr 17, 2015)

HKJ said:


> I suppose you mean using a Apple usb power supply and that is fine, the problem is all the cheap Chinese ones.



Yes,sorry,to clarify the actual USB power supply/plug.

Cheers ven:thumbsup:


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## HKJ (Apr 17, 2015)

ven said:


> Yes,sorry,to clarify the actual USB power supply/plug.



The 12W Apple charger is very good, I have just published a review of it.


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## ven (Apr 17, 2015)

HKJ said:


> The 12W Apple charger is very good, I have just published a review of it.




As always:bow:thank you

Just looked at my latest chargers, iphone 6+ and the air2,air 2 is 10W on mine








I wonder why 10w and 12w differences,more so if regulated in the ipad for example........

Cheers ven:thumbsup:


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## Christoph (Apr 17, 2015)

my VP1 plug will fit into my VC4  
C


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## HKJ (Apr 17, 2015)

ven said:


> I wonder why 10w and 12w differences,more so if regulated in the ipad for example........



Looks like yours is an older generation, they have probably increased the power to charge some of the new iPads faster.



Christoph said:


> my VP1 plug will fit into my VC4



Then you have to be careful. I wonder why they have changed the connector.


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## ven (Apr 17, 2015)

HKJ said:


> Looks like yours is an older generation, they have probably increased the power to charge some of the new iPads faster.
> 
> 
> 
> ...


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## XTAR Light (Apr 30, 2015)

Thanks for the great review.


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## jc9121 (Aug 1, 2015)

Hello All,

thank you for the detailed review of this charger!
I bought this charger because somewhere else - probably on this forum - it was mentioned that the internal charger in my flashlight is useless.

I just powered it up today and I bought 3x 26650 batteries (eFest 5200mAh).
I plugged in two cells in channels 1 & 4 and went out to lunch. When I came back (~2hrs later) it was still at ~600mAh and the charge current was very low ~0.2A.
I thought it could be due to my apple USB wall wart - so i changed it to a Samsung one and that gave a more respectable 0.6A.
However in doing so the mAh reading was reset to 0.

What does the mAh reading actually show - charge delivered to the batteries or actual charge in the batteries?

Sorry for the basic question - I am used to chargers with just a green and red led to indicate charging and complete.

br
James


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## RI Chevy (Aug 1, 2015)

Welcome to the Forum! :welcome:


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## HKJ (Aug 1, 2015)

jc9121 said:


> I plugged in two cells in channels 1 & 4 and went out to lunch. When I came back (~2hrs later) it was still at ~600mAh and the charge current was very low ~0.2A.
> I thought it could be due to my apple USB wall wart - so i changed it to a Samsung one and that gave a more respectable 0.6A.



It can be the cables, it is always a good idea to use short and thick usb cables when charging.




jc9121 said:


> However in doing so the mAh reading was reset to 0.
> 
> What does the mAh reading actually show - charge delivered to the batteries or actual charge in the batteries?



The mAh reading is how much current is filled into the cells, not how much is in the cells.


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## jc9121 (Aug 1, 2015)

Thank you for your quick response.

So since it shows the charge delivered to the cells - i wonder if there was any way I can use this charger to weed out dodgy batteries which do not provide the advertised mAh.

I understand that having one poor battery in a group can significantly degrade performance overall.

On car batteries (Lead-Acid) I used to run a drop test where a known load is applied and if the voltage drops below 9V then the battery is not good enough for use.
Is there such a test on these Li-Ion batteries?

Sorry for the detailed questions - I use my batteries for a flash-light while swimming and changing batteries in the sea may lead to salt water ingress into the flash-light so i'd like to be sure the batteries I put in it before entering the water are good ones.

thank you!
br
James


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## ven (Aug 1, 2015)

Having had a while now i am full of discontent ,tried different apple chargers which cover the required 5v 2.1a ,even bought extra plugs and same issue. Then paid almost £15 from a UK shop for a "good" travel charger ,again rated at 5.0VDC/2100mah. Again 2 cells in 1+4 with 1a charge only lasted minutes before dropping to 0.75 or 0.5 later...........i can not get a 1a charge rate for 2 cells for the charge duration.

One cell i can manage........useless .

So my overall expectations ,now weeks later is disappointment, in what is a poor design imo. Why cant Xtar do a proper plug option for it........?? I dare not try their 5v 2.1a effort(looks very cheap and suspect its charger and not plug/s) as i have bought better quality ones with no avail. Maybe it is faulty .....my cost on this charger has doubled with buying new USB plugs(not cheapo ones)to get this working as should(never again) . 

Shame as i like the nimh support over my vp4,now i have a jack of all trades in the opus BT-C3100 V2.2 ............should have missed the vc4 out

Odd reading has been 2.xxV on a 3.8v cell,remove ,re-fit and back to a more accurate display...........guess confidence is lost now and can't trust it. The vp1/2/4 /sp1 and wp6II have been perfect..... will take this as an Xtar bad apple(for me anyway).


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## HKJ (Aug 1, 2015)

jc9121 said:


> So since it shows the charge delivered to the cells - i wonder if there was any way I can use this charger to weed out dodgy batteries which do not provide the advertised mAh.



Yes, as long as you can discharge the batteries in a controlled way, i.e. you need something that uses one battery and automatic turn off when the battery is empty.
Then you can charge the batteries and compare the mAh.



jc9121 said:


> I understand that having one poor battery in a group can significantly degrade performance overall.



Correct, when you uses batteries in series.



jc9121 said:


> On car batteries (Lead-Acid) I used to run a drop test where a known load is applied and if the voltage drops below 9V then the battery is not good enough for use.
> Is there such a test on these Li-Ion batteries?



You can something equivalent on LiIon with a voltmeter and a resistor (1ohm power resistor is fine). The actual drop will depend on the battery, but all batteries used together must have about the same drop.
Checking tailcap current on a single cell high power flashlight can also be used, all batteries must again show about the same value.


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## HKJ (Aug 1, 2015)

ven said:


> Having had a while now i am full of discontent ,tried different apple chargers which cover the required 5v 2.1a ,even bought extra plugs and same issue. Then paid almost £15 from a UK shop for a "good" travel charger ,again rated at 5.0VDC/2100mah. Again 2 cells in 1+4 with 1a charge only lasted minutes before dropping to 0.75 or 0.5 later...........i can not get a 1a charge rate for 2 cells for the charge duration.



Are you are using more cable than the cable supplied with VC4?



ven said:


> One cell i can manage........useless .



You obvious need your cells charged fast, for many people it is not a huge problem if it takes a few hours extra to charge.

My guess is that either you have been very unlucky with the usb power supplies (i.e. they are all max. 5.0 volt) or your copy of the VC4 is extra critical with the charge voltage.


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## jc9121 (Aug 1, 2015)

HKJ said:


> Yes, as long as you can discharge the batteries in a controlled way, i.e. you need something that uses one battery and automatic turn off when the battery is empty.
> Then you can charge the batteries and compare the mAh.
> 
> 
> ...



Thank you for your response once again.

I can try to compare the tailcap voltages of the batteries in my light when they finish charging.


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## ven (Aug 1, 2015)

Hi HKJ,yes i use the original cable supplied with the vc4,tried a good few plugs now,ordered a 5v 3a as a last port of call.

I dont mind a slightly slower charge but it can drop at times down to 0.25 or bellow the mid way 0.5a on display. I would expect to see 1a on bay 1+4 and using all bays a drop to 0.5a. In effect its like using all 4 bays for charging yet only 1+4 are occupied by 18650 cells. It does the same on AA eneloops too,so its either the cable/plug.......or charger itself! Unfortunately i dont have another usb cable to fit the charger.........this i am working on


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## Timothybil (Aug 1, 2015)

Get yourself one of the ZTS battery testers. I know at least one model will test 3.7v Li-Ion cells. It only provides a five step readout, but if you test the set on a regular basis as you use it, any cell that is not pulling its weight will show up with the ZTS tester. If one cell consistently tests lower than the others, it is a pretty good indicator that it isn't holding its charge as well as it should.


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## ven (Aug 1, 2015)

Hi there,thanks for suggestion,can get readings off the opus(resistance/capacity) but cells i have tried have been from older to new/ish and tried many. No issues on other chargers at all. So i cant even say its a specific cell/s............defo charger/cable/plug or maybe all....


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## HKJ (Aug 1, 2015)

Timothybil said:


> Get yourself one of the ZTS battery testers. I know at least one model will test 3.7v Li-Ion cells. It only provides a five step readout, but if you test the set on a regular basis as you use it, any cell that is not pulling its weight will show up with the ZTS tester. If one cell consistently tests lower than the others, it is a pretty good indicator that it isn't holding its charge as well as it should.



With a LiIon cell a voltmeter/DMM is better, for most other battery types the ZTS is best.


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## HKJ (Aug 1, 2015)

jc9121 said:


> I can try to compare the tailcap voltages of the batteries in my light when they finish charging.



Not voltage, *current*.



ven said:


> Hi HKJ,yes i use the original cable supplied with the vc4,tried a good few plugs now,ordered a 5v 3a as a last port of call.



It is not really the ampere that is important (As long as it can deliver enough), but the voltage. The VC4 uses the voltage to adjust the charge current and it only needs to drop a bit below 5.0 before it will reduce the current.


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## ven (Aug 1, 2015)

HKJ said:


> Not voltage, *current*.
> 
> 
> 
> It is not really the ampere that is important (As long as it can deliver enough), but the voltage. The VC4 uses the voltage to adjust the charge current and it only needs to drop a bit below 5.0 before it will reduce the current.




Having tried apple air2 chargers(bought another to use separate to my ipad),even tried older ipad chargers which should be fine on paper,i am a little stuck now


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## zipplet (Aug 1, 2015)

Hi ven,

Do you have any deoxit or contact cleaner? I have had dirty USB sockets transfer dirt to plugs causing a voltage drop. I'd recommend cleaning the USB cable for your VC4 (both ends), the power input socket on the VC4 and the USB socket on your apple charger. 

Re-test after doing that, keep using the apple ipad charger as they are known to work well with the VC4.

If you want to just verify this theory, try pulling the USB plug slightly out of the power supply and see if things improve. Usually they will as a different contact point will be in use. If things are really dirty that might not help though.

(Do you have a USB voltmeter? They are great for situations like this)


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## ven (Aug 1, 2015)

Hi zipplet,yes i have an xtar usb for checking the voltage so will double check(cant remember results now) will try that too,is odd as everything new. 

Will try and get back:thumbsup:


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## ven (Aug 1, 2015)

Two plugs i am testing now



Apple



Both same results









Xtar usb showed 5.1v or 5.3v at one short time.........

Everything usb wise is spotless,tried to clean but nothing to clean,Q tip spotless.


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## zipplet (Aug 2, 2015)

Hmm, I'm not sure what to suggest. Your charger or cable might be faulty.

To be honest, I would contact XTAR and get them to try sending you a replacement cable. I don't think they would quibble over that.


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## ven (Aug 2, 2015)

Hi Zipplet,the mail was sent yesterday suggesting cable or also if they had a USB plug thats known to work. Just to add,the cable is not tied up,its fully undone from the tie.

Will see how i get on

Cheers...........least my "noisy" bt-c3100 works as it should,luckily i have a good few Xtar chargers,if it was the only one and i depended on it,i would not be happy.................


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## KenSrf (Aug 2, 2015)

I am a bit confused reading the test and the thread and would appreciate some clarifications.

Is the reason why the charging was so slow when charging four 18650s batteries (1100 seconds, twice as long as NiteCore D4) because of the resistance from the additional cables you had to use to perform the tests? Should one expect faster charging with high quality 5V adapter, without needing to increase the voltage above 5V?

And if so, what would qualify as a high quality adapter? I don't have a high current 5V power supply (ignoring old PC PSUs, which I find to be too bulky for this purpose). Previously mentioned 12W apple costs nearly as much as the charger, and it seems that even then some people are not getting specified charging currents.

I initially thought that this charger would be better and faster than D4 but now I am no longer sure.


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## HKJ (Aug 3, 2015)

KenSrf said:


> Is the reason why the charging was so slow when charging four 18650s batteries (1100 seconds, twice as long as NiteCore D4) because of the resistance from the additional cables you had to use to perform the tests? Should one expect faster charging with high quality 5V adapter, without needing to increase the voltage above 5V?



Yes, but both charger and usb power can have tolerances on voltage, making it difficult to predict the exact result (I.e. if you get full charging speed).



KenSrf said:


> And if so, what would qualify as a high quality adapter? I don't have a high current 5V power supply (ignoring old PC PSUs, which I find to be too bulky for this purpose). Previously mentioned 12W apple costs nearly as much as the charger, and it seems that even then some people are not getting specified charging currents.



A good adapter is something that keeps a high output voltage, even at 2A. You can check my tests for candidates: http://lygte-info.dk/info/ChargerIndex UK.html (Xtar has one that looks promising).


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## voodoogreg (Aug 6, 2015)

Been lurking on this thread since I own one of these, been a while since I posted on CPF, Ven I think your unit is screwed. albeit a little slow I find mine to charge Li-ion's and Ni-mh's full and accurate, without blasting them too hard. I just ordered another to take on the road (union musician, and I can't have wireless unit's or flashlight's, pedalboard light's etc failing, ever...)
I did invest in a couple of Anker 40W 5-port (71AN7105) HKJ reviewed very well, but even on an std issue apple 1ma it seem's about the same. Just my experience. VG

ps, De-oxit is a must for my road gear, but alcohol and a tooth brush should be enough to clear any kinda home dirt off even old USB's...


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## KenSrf (Aug 19, 2015)

HKJ said:


> Increasing the usb voltage to 5.2V to compensate for wire losses improves the charge speed.
> The display shows 2781mAh 2764mAh 2884mAh 2857mAh.


In your opinion why is charging rate dropping from 500mA to about 350mA after two hours of charging?


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## ChrisGarrett (Aug 19, 2015)

I have a new Apple 12w 2.4A wall wart, but right now, I'm using my Ruinovo 4x18650 power bank and my VC4 now, having just discharged two Sanyo 2600mAh FMs down to 3.62v and I'm getting 1.07A/1.08A into the Xtar via my Xtar current/voltmeter at 4.91v after 90 minutes. Charge current is 600mA, but started out at 1A.

I'm about 900mAh into the charge. Display is off.

Chris


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## KenSrf (Aug 20, 2015)

HKJ said:


> Yes, but both charger and usb power can have tolerances on voltage, making it difficult to predict the exact result (I.e. if you get full charging speed).
> 
> 
> 
> A good adapter is something that keeps a high output voltage, even at 2A. You can check my tests for candidates: http://lygte-info.dk/info/ChargerIndex UK.html (Xtar has one that looks promising).


I missed this message, thanks.

Did you ever test this charger with Xtar adapter, that seems to be a nice match for their charger given the higher voltage?


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## HKJ (Aug 20, 2015)

KenSrf said:


> Did you ever test this charger with Xtar adapter, that seems to be a nice match for their charger given the higher voltage?



No, but I would also expect it to be a good match.


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## bmwsancho (Aug 20, 2015)

MY VC4 had the exact same symptoms as stated in this thread - two 18650s in the outer slots, low charging rate. When I even touched the USB cable the rate dropped to 0.0A and the green lights came up (charging stopped) and the display showed "full". power cycling the device restarted the charging process. 

The device was classified as defect and exchanged by the seller. The new VC4 is a lot better but still shows slow charging currents. One aspect I have noted is that when checking up on the USB voltage with a "charger doctor" the overall current going into the VC4 is about half compared to what the device is showing on the display.

I have tried iPad Air 2 charger, iPad 3 (12W) charger, Samsung tablet charger (I believe 2.1A) - all results are the same.


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## voodoogreg (Aug 20, 2015)

bmwsancho said:


> MY VC4 had the exact same symptoms as stated in this thread - two 18650s in the outer slots, low charging rate. When I even touched the USB cable the rate dropped to 0.0A and the green lights came up (charging stopped) and the display showed "full". power cycling the device restarted the charging process.
> 
> The device was classified as defect and exchanged by the seller. The new VC4 is a lot better but still shows slow charging currents. One aspect I have noted is that when checking up on the USB voltage with a "charger doctor" the overall current going into the VC4 is about half compared to what the device is showing on the display.
> 
> I have tried iPad Air 2 charger, iPad 3 (12W) charger, Samsung tablet charger (I believe 2.1A) - all results are the same.


 
Interesting, I have an anchor iq 5 port that outputs whatever the device needs (up to I think 5.2 v @ 2.4ma) ill check my cable, but aside from being a little slow, I seem a get a full charge. VG


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## ChrisGarrett (Aug 20, 2015)

voodoogreg said:


> Interesting, I have an anchor iq 5 port that outputs whatever the device needs (up to I think 5.2 v @ 2.4ma) ill check my cable, but aside from being a little slow, I seem a get a full charge. VG



I'm only a sample size of one, but my new XP1 Hummingbird won't charge NiMH batteries up at the 500mA rate, but it will at 250mA and li-ions will charge up at the 500mA rate.

My VC4 doesn't get used a lot, but I have used it to charge some NiMH batteries with high IRs and it works, albeit a bit slowly at 500mA.

It's that 1A rate that I can't seem to hit either with NiMH, although I need to double check this and then li-ion 18650s that have been well depleted. My two Sanyo 2600 FMs referenced above, did take 2200mAh worth of current before I fell asleep for a bit and they came off at 4.19 and 4.18, so totally within spec there.

I just don't see it on the display, or from my Xtar volt/current meter.

I can live with this and the XP1, since these USB chargers are more Zombie/SHTF back-ups for but I think that we're seeing a trend here and I need to fiddle with the NiMH side of things even trying only one battery/cell at 1A.

Frankly, as much as I love Xtar, my MP1S undercharges well below spec, so it's glitchy, my VP2 was recalled, my XP1 doesn't charge up at 500mA on NiMH batteries and now the VP4 might be pumping less than 1A's worth of current into two slots. My MC1+ and WP2 II are both stellar.

Chris


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## ven (Aug 20, 2015)

Interesting Chiris ,mr bmw seems to be having similar issues to myself:thinking:

I am thinking 1 of 2 things here,early unit with gremlin maybe...........Or could it be possible that the charger is detecting cells past their best and lowering the charge rate(maybe too advanced i dont know but a very intelligent charger). I will try it on some fresh LG IMR cells when i have time! Iirc the 30Q charged issue free at the start with a nice 1a rate in bays 1+4. 
Since then i have been charging cells that are used constantly,sometimes a couple of charges in one day of the same cell. Basically i am charging cells that are over 12 months old and seen 100s of charges(long shot but maybe resistance built up in cells and mr vc4 thinks lets slow this show down).

My vp4 has been spot on just like my vp1 and vp2, however i am only going off what it shows on the display which is a set rate(1a) and not a variable. 

To help get to the bottom of this i need to get the vc4 and another xtar charger going at the same time with similar discharged cells............timed and see how long!

Greg could be right and it could be screwed


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## ChrisGarrett (Aug 20, 2015)

Ven,

I'm running down some Duraloop Ion Core AAs and I'm going to fiddle with them, the VC4 and the Xtar v/c meter. I guess in the last month, I wasn't really looking to verify my VC4, until the other night with the 2 Sanyo FMs.

I've been using my Ruinovo power bank to charge stuff up, just to play with it and it now seems that its 2A INPUT charge port has gone **** up on me and I'm only getting 250mA (for 4x18650s,) so forever! The 1A port pulls 1A through the Xtar v/c meter, so I'm good there.

I realize that this stuff is cheaply sourced electronics, but I am experiencing some non-imaginary issues.

Chris


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## ven (Aug 20, 2015)

Look forward to your findings Chris, with more time i will try my best to test mine tomorrow . Will try new and old cell comparisons and see if anything changes. I am sure that my vc4 was spot on at 1st,charging the 30q and LG cells at 1a issue free(99.9% sure). Only after a week or two did i notice the charge rate drop to .5a or even less at times. At the time i had some chargers set up next to me in the front room(to much displeasure of the boss). 

I have been relegated to the floor area now thanks to spike the dragon!! :laughing: Still in my sight though


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## Necromncr (Aug 20, 2015)

Hi!

I am new here and I want to thank you HKJ and others for all these great articles and reviews. I am slowly getting my feet wet with all of this and researching everything I can.

What I wanted to know is if I am reading and understanding these graphs right and whether I am comparing apples with apples. It seems that VC4 is undercharging NIMH batteries?

For example VC4 is charging eneloopXX to only 2000 mAh, while D4 is charging it to around 2300 mAh, and Panasonic BQ-CC16 NIMH charger to 2500 mAh.

Same for eneloopAAA, Xtar charges to 670 mAh, D4 to 810 mAh and Panasonic to 910.

And for eneloopPro, Xtar 2520, Panasonic 3350.

What is going on there?


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## HKJ (Aug 21, 2015)

Necromncr said:


> What is going on there?



Batteries looses capacity with age, i.e. you cannot always expect a XX or Pro cell to be 2500mA. The best way to see if a cell is filled is to look at the temperature track, when the temperature starts to raise the NiMH cell is basically filled.


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## ChrisGarrett (Aug 21, 2015)

I don't know...I just depleted 4 Duracell Ion Core 2400mAh AAs down to ~1.09v-1.10v after a 20 minute rest and just pumped 2220mAh, 2345mAh and 2380mAh into 3 of them. Not all chargers measure things the same way.

My LaCrosse BC-700 seems to read about 10% higher than my Maha C-9000, with the same/similar batteries.

If you're not starting the 'charge' process with the batteries/cells at the exact same voltage and if you're not using cells/batteries that are in similar condition, you're going to get a variation anyhow.

Chris


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## ChrisGarrett (Aug 21, 2015)

Here's what I'm seeing with my VC4, my Apple 12w wall wart and Xtar v/c meter:

1 Duracell Ion Core 2400 discharged down to ~1.10v, after a good rest.

Slot 1: After a 10 minute beginning, where I only pumped 10mAh into the battery, the meter began reading 5.17v and a .37A current. The VC4 was showing the 1A charging rate.

After an hour, the meter readings were the same and the VC4 showed 1A charging and about 670mAh. After two hours, the meter was 5.17v and .37A and the charger showed about 1350mAh. After 3 hours, about 2020mAh and the meter readings were the same.

I pumped 2220mAh into that battery, but didn't get an ending time.

This tells me that with one battery in slot one, the VC4 put about 670mAh per hour into the Duraloop and not ~1000mAh.

Just now, I finished two of the Duraloops, both around 1.10v to start and placed them in slots 1 and 4, for a supposed 1A charge rate. 

10 minutes go by and 10mAh per battery, before things kick in. Basically the meter read 5.11v and .73A and after an hour, I had my ~670mAh for both slots. At 2 hours, the meter is the same and capacity doubled. 3 hours, we're holding steady at ~670mAh per hour and my final capacities were 2345mAh and 2380-85mAh and a little over 3.5 hours, however, in the last hour, the VC4 meter went down to .9A, so not exactly 1A.

I've just started the fourth Duraloop in Slot 4 and the meter's reading consistently with the single slot 1 numbers, which started this test out.

We really have to a) assume that the meter on the VC4 is fairly accurate and b) we need to time this and check things at hour intervals to get an idea of what our chargers are actually pumping into our cells/batteries.

Chris


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## keithy (Aug 21, 2015)

Just a query about the backlight for people who also have this charger. 

With mine, I've just started turning off the backlight by holding the CH button down for a few seconds when charging 4 x NiMHs. When checking laster to see if the batteries have completed charging, I've noticed that the backlight is turned back on. 

Is this normal behavior? The manual says the backlight goes into a power saving mode after a while of no interaction, or pressing down for a few seconds turns off the backlight, but not that it turns back on by itself. 

Just wondering if it could be my USB power supply or if it's normal for the VC4.


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## ven (Aug 21, 2015)

Thanks for feedback Chris,interesting results there..........makes me wonder on other chargers too! 

I did a simpleton test in comparison  This time i used 2 sets of new LG H1 cells,bays 1+4 for the 1a rate...........guess what

1st 2 cells all the way till termination showing 1a(granted only what it shows on screen but not showing the 0.5a etc of past)
I only squeezed 200mah in the cells, but being the last part of the charge it showed no reduction even though the slowest part. On charge for around 1/2hr till termination.




Then i swapped for the other 2 LG H1 cells




Again issue free charging according to display



Older well used cells,again 1a showing where last time it dropped straight away



All 4 bays showing .5a which of course is spot on



Some new LG cells just started off




Will see over the weekend,will carry on using it as a primary charger(will be used up to 14hrs a day).


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## HKJ (Aug 21, 2015)

ven said:


> 1st 2 cells all the way till termination showing 1a(granted only what it shows on screen but not showing the 0.5a etc of past)
> I only squeezed 200mah in the cells, but being the last part of the charge it showed no reduction even though the slowest part. On charge for around 1/2hr till termination.



From the first post in this thread: The current dial only shows the *maximum* charge current, the *actual current is lower* when the battery is in the CV phase.


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## ven (Aug 21, 2015)

Thanks for the info HKJ, i will look back over again


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## ven (Aug 21, 2015)

keithy said:


> Just a query about the backlight for people who also have this charger.
> 
> With mine, I've just started turning off the backlight by holding the CH button down for a few seconds when charging 4 x NiMHs. When checking laster to see if the batteries have completed charging, I've noticed that the backlight is turned back on.
> 
> ...



Keithy,my back light stays on for the full charge duration.


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## ChrisGarrett (Aug 21, 2015)

keithy said:


> Just a query about the backlight for people who also have this charger.
> 
> With mine, I've just started turning off the backlight by holding the CH button down for a few seconds when charging 4 x NiMHs. When checking laster to see if the batteries have completed charging, I've noticed that the backlight is turned back on.
> 
> ...



IME, there are three levels to the backlight: fully on, dim and off.

It seems to me that if something happens, like a battery finishes charging, or a fresh cell is inserted, when the display is in the dim position, or even off, it will pop back on and then go into the 'dim mode' after a minute, or whatever it is.

Chris


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## Necromncr (Aug 21, 2015)

HKJ said:


> Batteries looses capacity with age, i.e. you cannot always expect a XX or Pro cell to be 2500mA. The best way to see if a cell is filled is to look at the temperature track, when the temperature starts to raise the NiMH cell is basically filled.


But you tested Xtar VC4 only one month after Panasonic BQ-CC16.


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## JohnSmith (Aug 21, 2015)

Does everyone find their VC4 voltage meters to be accurate? Mine seem to read high with lithium ion cells. Cells reading as 3.8V with my multimeter appear as 4.0V in the VC4, and cells at 4.0V max out the VC4 meter reading at 4.2V. Anyone else experience this or know what may be happening in my charger?


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## keithy (Aug 22, 2015)

ChrisGarrett said:


> IME, there are three levels to the backlight: fully on, dim and off.
> 
> It seems to me that if something happens, like a battery finishes charging, or a fresh cell is inserted, when the display is in the dim position, or even off, it will pop back on and then go into the 'dim mode' after a minute, or whatever it is.



Thanks Chris (and Ven). It does seem like that's whats happening. When the display backlight is set to off, it comes back on when battery finishes charging. However, I've been testing my various USB power supplies with this charger, and found that on my Poweradd 25W http://www.ipoweradd.com/poweradd-2...ne-6-6s-5-5s-4-4s-ipad-tablets-psp_p1311.html 2.1A socket it was showing some weirdness with 4xAAs. It was only charging all four 2300mAh NiMHs at 0.1A. 

And when it completed and the CH# leds were green, the backlight did not come on, but it only reported adding 470ish mAh into all cells. All cells were depleted, so it should have added at least 2000 mAh. I unplugged from the Poweradd, and used an Asus 2.1A charger, and three of the cells then charged up an additional 1500ish mAh, while the last one added just over 2000mAh. 

The poweradd 2.1A socket had no problems charging an iPad at full rate, so it seems that the VC4 is really fussy about the USB power source.


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## HKJ (Aug 22, 2015)

Necromncr said:


> But you tested Xtar VC4 only one month after Panasonic BQ-CC16.



My testing and publishing is not always synchronized, I do usual have a few reviews as backup. These review may lay around for many months, to be used when I do not have anything else ready.

I do also have multiple cells to test with (4xXX, 4xPro, 4xPowerex, 8xEneloop). I have replaced the Eneloop earlier this year, but the other cells are a bit older.


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## ven (Aug 22, 2015)

keithy said:


> The poweradd 2.1A socket had no problems charging an iPad at full rate, so it seems that the VC4 is really fussy about the USB power source.




+1 All my plugs that i have tried are rated 5v 2.1a , admittedly they might not meet their rating and allow enough juice to flow through! 

Have you tried holding the button for 1.5s to switch off/on ? When my vc4 is in use(rotation with other chargers) it is only used during the day,powered off at night when i go to bed. However when its used again it does have the display on right from powering on and through the charge.


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## Necromncr (Aug 23, 2015)

HKJ said:


> My testing and publishing is not always synchronized, I do usual have a few reviews as backup. These review may lay around for many months, to be used when I do not have anything else ready.
> 
> I do also have multiple cells to test with (4xXX, 4xPro, 4xPowerex, 8xEneloop). I have replaced the Eneloop earlier this year, but the other cells are a bit older.


Got it!

Thanks


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## HKJ (Aug 23, 2015)

Necromncr said:


> Got it!



The bulk of my testing is with (white) eneloops, but I try to include some other cells. The problem is getting common cells that are not eneloop based, generally I do only expect a test set to last for between one and two years. If anybody has good ideas for (common) test cells or even wish to donate (I am fairly limited in what brands I can get locally) a 4 pack of cells I am always listening.


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## Xiphex (Sep 3, 2015)

I was browsing though the NCIX website and found a StarTech 'USB to 5.5mm' cable. Link

Yay, Spares! one for my USB iBoost 10 port charge station on desk & one for the car, Original cable keep for emergency.


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## keithy (Oct 9, 2015)

I've just had my VC4 miss termination on two NiMHs while I was charging a set of four Duracell 1700mAh batteries.

Slot 1 was showing finished at 2200mAh, and slot 3 was 2700mAh and still charging. The other two in slots 2+4 were around 1750mAh/1800mAh. The battery in slot 3 that was still charging was hot when I pulled it out. 

The batteries are the green/black Duracell Accu Rechargeables bought around 2011/2012. 

Is there a reason the VC4 missed termination on these two?


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## sidecross (Oct 14, 2015)

I just purchased this charger to go with my two VC2 Plus Master chargers; I use a Anker PowerPort 5 which can handle up to 5 usb connections at 2.1 amps. I can charge up 8 18650's while just using one wall plug outlet.


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## CelticCross74 (Oct 14, 2015)

Wow! What a thread! It seems the VC4's are all over the place in how they charge from unit to unit? I have had my VC4 for a few months now and yes it would start to drop voltage and lag really slowly especially with 3 or more cells in it. Then one day I decided to NOT plug the VC4 into the Xtar wal wart but into my Verizon 5 volt 2.4amp travel charger. The Verizon unit is meant for something called "lightening"? Anyways the VC4 now has zero lag whatsoever. I have not seen the voltage meter drop below 1 amp or half an amp for 3 or more cells at all using this Verizon wall wart. Was going to buy another VC4 and another Verizon "lightening" USB wall wart. Ever since I switched USB adapters to the Verizon unit the VC4 seems to charge more accurately either that or its just wishful thinking. Still the Verizon unit was like giving the VC4 race gas I love it


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## paubin (Oct 15, 2015)

I was just looking into this charger and with your review it has helped me make the decision. Thank you for your time!


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## Overclocker (Oct 22, 2015)

hi HKJ,

both the VC4 and Lii-500 don't do delta-V termination but:

a) VC4 terminates at about 1.52v

b) Lii-500 terminates at about 1.47v


but which one is better in the REAL WORLD? assuming the nimh cells aren't new. maybe 100 cycles in them


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## HKJ (Oct 22, 2015)

Overclocker said:


> but which one is better in the REAL WORLD? assuming the nimh cells aren't new. maybe 100 cycles in them



If you do voltage termination the lower value is safer, but needs to be followed by a top-off charge to fill the batteries. There is also another problem: voltage termination will vary slightly with temperature.
With eneloop 1.52 volt works fine, but some other cells may have problems.


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## Overclocker (Oct 22, 2015)

HKJ said:


> If you do voltage termination the lower value is safer, but needs to be followed by a top-off charge to fill the batteries. There is also another problem: voltage termination will vary slightly with temperature.
> With eneloop 1.52 volt works fine, but some other cells may have problems.





thanks. they just can't get these things right:

BT-C3100 uses 2+ amp pulses. otherwise great

Lii-500 no delta-V, no top-off. otherwise great

VC4. limited by USB power. no delta-v. otherwise great

why isn't there a really good charger LOL


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## HKJ (Oct 22, 2015)

Overclocker said:


> Lii-500 no delta-V, no top-off. otherwise great



You do not want both, either -dv/dt or constant voltage + top-off


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## Overclocker (Oct 22, 2015)

HKJ said:


> You do not want both, either -dv/dt or constant voltage + top-off



yes of course.


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## CanoeBeyond (Nov 10, 2015)

I joined to post some time sensitive information on the VC4 charger that I thought would be some benefit to users (my experiences and a link to a flash sale (still active at this point)). Registering here is relatively difficult but I've gotten a lot of good information here. Thought I would do some payback for the service. My 2 posts are still not showing up though and I haven't received any feedback from admins. Wondering?

Thanks/Ed


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## CanoeBeyond (Nov 10, 2015)

For some reason my 3rd post showed up but not my first 2 posts with my impressions of the VC4 versus my other chargers. Hopefully they'll show up soon. Here's the flash deal I found and purchased my VC4. It's still valid at this point (actually $16.68 now):

http://www.gearbest.com/chargers/pp_160440.html?wid=2

Only valid at the US warehouse it seems. Just ordered another one at that price for a gift.


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## CanoeBeyond (Nov 19, 2015)

Sorry guys, somehow my first two posts must have been lost in "approval heaven" and the sale appears to be over. At least I think I'm able to post normally now so if I see this deal again I'll post it.


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## OriginalStevenH (Nov 21, 2015)

Ok. So I'm really confused at this point... I own 1 Nitecore I4 2 Nite Core D4 and I just got the Xtar VC4. I really like the VC4 because it allows me to charge the C and D batteries. I've noticed first off that the C batteries Tenergy LSD 4000mah weren't being charged fully in the D4 or the I4. I didn't think there was a problem with the AA/AAA and 18650's. Now I'm really confused. I took some LSD AmazonBasic Blacks High capacity AA's I just charged about 2 days ago and tested them in the charger. I was shocked to see that it was not fully charged. almost 700mah and then several other batteries I tested are showing not fully charged... although the Lithium ion's are charged with only 40mah give or take after the nitecore D4 has charged it completely... So do I have a defective charger? or what? these are brand new batteries and I trust that since the AmazonBasic High capacity batteries are equivalent if not the same as the 2nd gen Eneloopxx. just see the pictures...


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## HKJ (Nov 22, 2015)

It is very difficult to detect a full NiMH battery, this means some chargers need up to 30 minutes to detect it. During that time they will be charging the cell.


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## CanoeBeyond (Nov 22, 2015)

Here's another VC4 sale from an e-mail I received:

http://www.gearbest.com/chargers/pp_160440.html

Then apply this code in your shopping cart: "VC4EM". The price should be $21.59 shipped (from China). Enjoy.

Edit: If nobody cares about these sales, let me know and I won't bother to post them. The VC4 is so far the best charger I've used (more than a few) and thought some might be interested.


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## TinderBox (UK) (Nov 23, 2015)

Good Review, Though i would prefer digits to dials, and the non-standard usb cable, crazy or what.

I have a couple of UK plug 12v 2a power supply's on order only £1.77 each as i have a couple of chargers that came with EU plug power adapters and they look awful sticking out the wall when using an UK adapter.

John.


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## hammerjoe (Nov 30, 2015)

So what is the consensus, is the VC4 a good charger or not? I am debating getting one or the XP4 for its ability to charge 1A on all of the 4 slots.


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## ChrisGarrett (Dec 1, 2015)

hammerjoe said:


> So what is the consensus, is the VC4 a good charger or not? I am debating getting one or the XP4 for its ability to charge 1A on all of the 4 slots.



I'm using mine right now and for an 'everyday' charger it's slow on 4 slots, much like the NiteCore i4 and D4. It's just the nature of the beast.

If you need faster 4 slot charging, the Opus BT-3100/3400 v. 2.2 will do I believe 1A for all four slots. Or the XP4 Panzer.

I bought the VC4 because I can use in on a 5V USB solar charger, or in a car that is so equipped.

Chris


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## ven (Dec 1, 2015)

Agree with Chris, no argument against it being a good charger,nicely made,good brand, flexible on chemistry. My gripe too was the slow charge when 4 bays are occupied(happened on just 1+4 bays as well). Dont think everyone suffers this though, sure a lot has to do with the plug. I wasted more money than the charger on finding the right plug! Not the smartest move but i dont like giving in...............i ended up giving in :laughing: 

Since then i picked up a good deal on the opus as Chris suggested, does exactly what it says on the tin! Display is not as fancy but it will give V readouts and mah in digital format.


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## hammerjoe (Dec 1, 2015)

I was thinking of getting a charger more for use as a backup in the car. That's why i want a charger that can do at least 2slots at 1A.
The vc4 fits the bill and also because i have a car usb charger that does 2.4A.

The xp4 is another contender but it seems that it heats up quite a bit and uses its own car plug.

Although i want it becuase of its capability to use in a car i also want to use it at home for regular charging. 
Very undecided right now...


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## Nuppet (Jan 15, 2016)

I've done some quick&dirty testing (new Eneloop Pro, used a few cycles) on the Xtar VC4 I just received from nkon.

With the Enerpower Flypower 2A that HKJ reviewed, the VC4 shows 1.0A during charging with cells in slots 1 and 2. With four cells VC4 shows 0.5A.

With the Sony EP 880 (5.0v, 1.5A) supplied with my phone I get 0.8A for two Eneloop Pro and 0.4A for four of them.

Measurements 20-30 minutes after start of charging.


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## ChrisGarrett (Jan 15, 2016)

Nuppet said:


> I've done some quick&dirty testing (new Eneloop Pro, used a few cycles) on the Xtar VC4 I just received from nkon.
> 
> With the Enerpower Flypower 2A that HKJ reviewed, the VC4 shows 1.0A during charging with cells in slots 1 and 2. With four cells VC4 shows 0.5A.
> 
> ...



Don't go by what the charger shows for amperage. Get a timer, or use your watch. Plug in your VC4 (to whatever wall wart you use,) start charging and begin timing.

In 30 minutes, come back and read the capacity counter. If you see 500mAh, then you're getting a 1A charging rate. If you see 250mAh, you're getting a 500mA rate, even if you're not exactly there.

My VC4 is all over the map, but it's not my primary charger and when the zombies are attacking, I'll be happy I have her.

Chris


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## Nuppet (Jan 15, 2016)

ChrisGarrett said:


> Don't go by what the charger shows for amperage. Get a timer, or use your watch. Plug in your VC4 (to whatever wall wart you use,) start charging and begin timing.
> 
> In 30 minutes, come back and read the capacity counter. If you see 500mAh, then you're getting a 1A charging rate. If you see 250mAh, you're getting a 500mA rate, even if you're not exactly there.
> 
> ...



Sure, that is my intention, but it was a quick&dirty test based upon posts/review that a weak PSU showed itself with a lower reported max current during charging. So far I've got good results as reported by the charger.


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## ChrisGarrett (Jan 15, 2016)

Nuppet said:


> Sure, that is my intention, but it was a quick&dirty test based upon posts/review that a weak PSU showed itself with a lower reported max current during charging. So far I've got good results as reported by the charger.



I've had two VC4s and I have the 12w 2.4A Apple OEM block and I've only seen true 1000mAh charging on a couple of instances when measured over 60 minutes and even 180 minutes. Also, I don't even know if I've seen 500mAh, with four slots filled, for even an hour.

And I'm not really alone on this one, either and I have one of those little Xtar USB voltage/current meters to give me a bit more info.

You need to time things out and see where you're at, according to the mAh meter, which HKJ has stated is fairly accurate.

Maybe I'll try another wall wart and see what I see?

Chris


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## sidecross (Jan 15, 2016)

XTAR VC4 has a maximum of 2 amps or 1 amp each to channel 1 and 4 or 500mAh to each channel when all 4 are being used. I use two XTAR VP2 chargers and it is the best investment I have made for the care of my batteries. I can even charge 18650's that support 4.35 volts which has a noticeable increase in output.


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## HKJ (Jan 16, 2016)

ChrisGarrett said:


> I have one of those little Xtar USB voltage/current meters to give me a bit more info.



I would not expect full charge current on the VC4 if you uses an USB meter. The meter will lose some voltage on on usb power and the VC4 will reduce the current.


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## zipplet (Jan 16, 2016)

I'd also like to emphasize the importance of clean USB connectors. You may be surprised that even brand new unused USB connectors can have "invisible" dirt. If you don't believe me, try this:

Take a piece of paper (recycled/rough paper works best), cut out a square roughly 10cm x 20cm. This takes some fiddling, but you want to roll it up to end up with a "flat stick" that can fit into the end of a USB plug slightly loosely. Then fold about 0.5cm of the strip over itself to form a "plug", and insert/remove it from a USB plug a few times. You'll get black lines on it - dirt!

Do this to the cable you use to power your VC4, you can also use a similar method to clean USB sockets (but not too much pressure). For me, this has fixed charging problems. I now make a habit of cleaning USB cables that are regularly removed/inserted every month or so to maintain performance. Devices like mobile phones will *not* tell you that they are charging slowly due to increased resistance!


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## Nuppet (Jan 17, 2016)

I discharged some Eneloop Pro and charged using the VC4 and the Enerpower Flypower 2A PSU.

The max current showed 1.0A all the time when charging in slot #1 and #4, and below are time (HH:MM) and mAh charged as shown by VC4 for slot #1 except the last line for #4. The actual charging seems to be about 750 mAh when charging in #1 and #4.

00:10 14
00:20 140
00:40 394
01:10 773
01:40 1153
02:10 1530
02:40 1914
03:10 2290
03:27 2503 (#1 green, charged)
03:34 2572 (#4 green, charged)


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## ChrisGarrett (Jan 18, 2016)

HKJ said:


> I would not expect full charge current on the VC4 if you uses an USB meter. The meter will lose some voltage on on usb power and the VC4 will reduce the current.



You've mentioned that to me in the past and I don't really use it often on my USB chargers, whether I'm charging with my XP1 on the PC, or the VC4 off of the Apple OEM WW. It's nice to fiddle with at certain times, but it seems that there's little room for error with the USB wall warts, USB chargers and the Xtar meter.

Chris


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## me_no_thing (Feb 6, 2016)

Hi

Just bought VC4.
Then i try charger my 2450 eneloop XX. after 1 hour slot 4 show full at 07xx mAh. But other 3 slots still charging and show 08xx mAh.
Then i just unplug power cord, then plug its again.
Now VC4 just start again from 0000 mAh ????

Try charging my NCR18650B, same situation.

Is its normal for VC4?

thanks


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## zipplet (Feb 6, 2016)

Yes this is normal behaviour. The VC4 does not store the charge status into non volatile memory.


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## me_no_thing (Feb 6, 2016)

Thanks for reply zipplet

But if batt get full charged, why when i unplug and plug power again, batt that was full, recharger again and about 20 minutes still not full filled again?


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## Dexx (Feb 12, 2016)

What are the pros/cons of the VC4 compared with the Nightcore I4?


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## ven (Feb 12, 2016)

I have both and i would say the vc4 is far nicer made, better quality plastic( price difference should reflect this) making it heavier , far nicer display, more useful display (obviously as the i4 does not have one). Not really a fair comparison tbh, maybe the D4 would be a closer one. The only gripe for me is the charging side, decent plug a must! It comes with a substantial USB lead, no plug as its designed as a portable(be it a big one) charger. The vc4 will(USB plug dependent) charge at 1a on bays 1+4 and 0.5 across the 4, the i4 drops to a painfully slow 0.35a iirc.............(0.5 is too slow and i find painful!!!) .

If quicker charging is not a big consideration then the vc4 makes a good choice, certainly with the flexibility of nimh charging(like the i4)

I prefer the digital read out of the vp series (1/2/4) over the dial, more accurate and easier to read on the eye imo.


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## akhyar (Feb 12, 2016)

I have both VC4 and i4 v2014 and I agree wholeheartedly with ven.
Decent USB plug for VC4 is a must, at least 2A plug like those use for iPad, Samsung Tab, etc.

Another thing I don't like about the i4 is that I always have to refer to the manual which slots are 0.75A if I want to charge max of 2 batteries at one go, coz if one of the 2 batteries is charged at the wrong slot, it will only charge at 0.375A.
On the VC4, it is clearly labelled that slots 1 and 4 can charge up to 1A if max of 2 batteries are charged at simultaneously.


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## CelticCross74 (Feb 12, 2016)

had my VC4 for months now and freaking love it. What I did not love about it was the Xtar specific wal wart for it. I just dont have the patience to watch a charge rate sink to .2 etc. So I did some research on wal warts and out of frustration found my iPhone 6 FireWire upgrade wall wart (made by Verizon its a big black cube with a red ring around the front that lights up when charging) and BAM! This wal wart has all 4 slots nailed to .5a when charging 4x18650. Also nails slots 1 and 4 to 1 amp no matter what I have in the slots. The amp meter does NOT move whatsoever. The VC4 now charges my cells up to 3 times faster its like I gave it race gas. No more slow drops to .2 amps for a half an hour BS etc. the iPhone 6 wal wart powers my VC4 to the wall I love it. As for "oh no that is to hard on the cells" I have yet to have a single issue with any cell I have charged on my turbo charged VC4. Sometimes NiMHs will get kind of warm but that is it. VC4 with iPhone 6 upgrade wal wart devours any charger Ive had before. Yes I understand after reading this thread that the VC4 often reads off what it is actually charging but with my hot wal wart powering it the amp meter is nailed as far as it will go. If it is reading off at all it is not by much at all.


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## ChrisGarrett (Feb 12, 2016)

Dexx said:


> What are the pros/cons of the VC4 compared with the Nightcore I4?



The former is 5v USB at 2.1A and can be run off of moderately powerful solar panels, or a quality 2.4A wall wart. The latter has a 12v input and can be run off of 12v solar panels, AC wall wart, or a 12v car cigarette adapter.

Both do NiMH and li-ion 3.7v cells. The Xtar 'can' do 500mA for 4 slots and 1A for two slots and the NiteCore i4 will do 4x375mA and 2x750mA.

The Xtar has a nice display showing mAh pumped in, charging rate and cell/battery voltages. The NC has a segmented bar display that progresses as the slots fill up.

I have both and prefer the VC4, but both chargers are apparently safe to use.

Chris


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## TinderBox (UK) (Feb 12, 2016)

I have been looking for a descent usb charger, I had my eye on the xtar vc4 but the only 2 slots at 1amp upsets me.

It would be nice if you could get 4x1amp if you plug in an 12volt psu as it has an barrel power connector anyway, and only 2x1amp when on 5volt usb.

John.


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## ChrisGarrett (Feb 12, 2016)

TinderBox (UK) said:


> I have been looking for a descent usb charger, I had my eye on the xtar vc4 but the only 2 slots at 1amp upsets me.
> 
> It would be nice if you could get 4x1amp if you plug in an 12volt psu as it has an barrel power connector anyway, and only 2x1amp when on 5volt usb.John.



Yeah, there are always trade-offs to this stuff and I really now only have it for SHTF scenarios since I got my Opus BT-3400 last month.

Like I said before, if you really, really need 1A for four slots, just get a second set of batteries and take your time.

It's there for my 14w Sunkingdom solar panel and so it serves a purpose, albeit a limited one for me.

Chris


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## Ki113rMi113r (Mar 19, 2016)

How does this compare to the BC1000 Alpha Power? Is this better or about the same. I'm thinking about buying one.


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## recDNA (Apr 3, 2016)

Does any American dealer sell the vc4 and sell a good 2.1 amp 5 volt wall adapter that really provides the 2.1 amps to the charger? Anybody try the Samsung 2 amp 5.3 volt wall adapter?


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## sidecross (Apr 3, 2016)

recDNA said:


> Does any American dealer sell the vc4 and sell a good 2.1 amp 5 volt wall adapter that really provides the 2.1 amps to the charger? Anybody try the Samsung 2 amp 5.3 volt wall adapter?


https://www.xtardirect.com/

Check under accessories.


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## ko4nrbs (Apr 3, 2016)

I use these with my VC4 chargers:
http://www.ebay.com/itm/Meanwell-RS...832923?hash=item51e29602db:g:Nu0AAOSwj0NUgLmj

Works like a charm!!
Bill


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## filibuster (Apr 3, 2016)

Yes they do, (follow sidecross's link). What I found to be the case with the XTAR 2.1A USB car adapter and USB wall adapter is that they output at a slightly higher voltage than is typical of other USB adapters. The Xtar USB adapters push the voltage to the high end of the USB spec or ~5.25V which in turn helps the VC4 maintain the power needed to charge more stably and without a problem. The higher initial voltage out of the adapter helps account for the voltage drop across the wire so more power gets from the USB adapter to the USB device or in this case the VC4 charger.

I've tested the VC4 against a good number of different USB ports and power sources and the higher voltage of the XTAR USB chargers makes all the difference in my 2x cells getting a 1A charge or 4x cells getting a consistent 500mA charge. Ive seen if the USB voltage on the wire drops below 5v then the charging current on the VC4 drops too.


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## recDNA (Apr 3, 2016)

sidecross said:


> https://www.xtardirect.com/
> 
> Check under accessories.


Then wait for delivery from China or are they in USA?


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## RI Chevy (Apr 3, 2016)

I think XTAR has a distribution facility in Florida.


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## scs (Apr 3, 2016)

RI Chevy said:


> I think XTAR has a distribution facility in Florida.



Is Xtardirect their outfit as well? I believe they are in California.


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## RI Chevy (Apr 3, 2016)

Not sure.


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## sidecross (Apr 3, 2016)

recDNA said:


> Then wait for delivery from China or are they in USA?


The link is xtar direct usa


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## Jakpro (Apr 3, 2016)

ko4nrbs said:


> I use these with my VC4 chargers:
> http://www.ebay.com/itm/Meanwell-RS...832923?hash=item51e29602db:g:Nu0AAOSwj0NUgLmj
> 
> Works like a charm!!
> Bill



Does it come with an AC cord? 

Are those USB ports on the side?


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## StorminMatt (Apr 6, 2016)

recDNA said:


> Does any American dealer sell the vc4 and sell a good 2.1 amp 5 volt wall adapter that really provides the 2.1 amps to the charger? Anybody try the Samsung 2 amp 5.3 volt wall adapter?



Although you cannot get it anywhere along with a VC4, you can always get a genuine Apple iPad wall wart. These can kick out a real 2.5A.


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## recDNA (Apr 6, 2016)

StorminMatt said:


> Although you cannot get it anywhere along with a VC4, you can always get a genuine Apple iPad wall wart. These can kick out a real 2.5A.


My wife has an ipad mini and an old original ipad. Do either of them have the adapter you speak of?


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## StorminMatt (Apr 6, 2016)

recDNA said:


> My wife has an ipad mini and an old original ipad. Do either of them have the adapter you speak of?



Not sure. At some point, Apple went from a 2.1A charger to a 2.5A charger. Not sure when they made the change. It WILL be printed on the charger, though.


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## V54_Fan (May 24, 2016)

Any idea why when I charge two 32650’s in the outside slots it drops to 0.6A charging?
The power adapter is an Apple 2.1A.


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## sdmf74 (May 26, 2016)

@ HKJ ~ Is this Xtar VC4 the best option in a 4 bay charger w/ mah display? Or is there a better unit out now?
I have a Nitecore D4 but want something to display mah. Charging mainly Eneloop AA&AAA and 18650 L-ion.

(For the VC4 I have an Orico DCP-5U 5 port super charger with 5v 7.2A)[h=1][/h]


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## HKJ (May 26, 2016)

sdmf74 said:


> @ HKJ ~ Is this Xtar VC4 the best option in a 4 bay charger w/ mah display? Or is there a better unit out now?
> I have a Nitecore D4 but want something to display mah. Charging mainly Eneloop AA&AAA and 18650 L-ion.
> 
> (For the VC4 I have an Orico DCP-5U 5 port super charger with 5v 7.2A)



It is a good option, but may not always charger at full speed, due to problems with the usb power.

For real analyzers the SkyRC MC3000 is the best, Opus BT-C3100 is also good.

Another brands with mAh is Skillhunt M4D, it looks good, but is fairly new to the market.


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## sdmf74 (May 27, 2016)

Im no expert on chargers but it appears as if some chargers like the skillhunt & many others only display mah that has been charged to the battery 
and others such as the skyRC & opus bt-c3400 & xtar vc4 can display the current total mah of the battery, is this correct?

One reason Im interested in checking the mah of my 18650 batts is to compare with reviews and possibly determine if they are counterfiets.


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## HKJ (May 27, 2016)

sdmf74 said:


> Im no expert on chargers but it appears as if some chargers like the skillhunt & many others only display mah that has been charged to the battery
> and others such as the skyRC & opus bt-c3400 & xtar vc4 can display the current total mah of the battery, is this correct?
> 
> One reason Im interested in checking the mah of my 18650 batts is to compare with reviews and possibly determine if they are counterfiets.



With LiIon charger and discharge mAh are just about equal. VC4 and other chargers with mAh display it is only the amount of current added that is shown, i.e. you will only get the capacity if you start with an empty battery.
An analyzing charger is much more convenient because it will discharge the batteries and will usual measure both discharged and charged mAh.


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## V54_Fan (May 29, 2016)

V54_Fan said:


> Any idea why when I charge two 32650’s in the outside slots it drops to 0.6A charging?
> The power adapter is an Apple 2.1A.



Helloooooooooo?????


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## sdmf74 (May 29, 2016)

HKJ said:


> With LiIon charger and discharge mAh are just about equal. VC4 and other chargers with mAh display it is only the amount of current added that is shown, i.e. you will only get the capacity if you start with an empty battery.
> An analyzing charger is much more convenient because it will discharge the batteries and will usual measure both discharged and charged mAh.



Thanks for the advice! after some research and learning curve I have decided on an Opus BT-C3400 V3.1 (selling my D4)


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

sdmf74 you do realise that firmware v3.1 discharges Li-ion to 3.1v when v2.2 discharges to 2.8v

John



sdmf74 said:


> Thanks for the advice! after some research and learning curve I have decided on an Opus BT-C3400 V3.1 (selling my D4)


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## sdmf74 (May 30, 2016)

TinderBox (UK) said:


> sdmf74 you do realise that firmware v3.1 discharges Li-ion to 3.1v when v2.2 discharges to 2.8v
> 
> John



No, will that give me innacurrate readings of my batteries total mah when doing a discharge/charge test???

Thats one of the reasons for getting this charger is to test total mah of my batteries
I always buy high quality cells (eneloop for AA/AAA and Samsung 25r, LGHG2 etc. for 18650's)
Unless of course I get duped and sold counterfeits which Im hoping this charger can help weed out.

I asked Robert at DC workshop what the difference between the 2 chargers was and he said this...

"For V3.1 I changed the discharge algorithm for Li-ion cells. Improves performance with low quality cells so as not to trip the internal protect on low quality cells."

Ironically I have the "soft cell cutoff" set at 3.09v in my Evolv Escribe software which is what is used to setup my mods for vaping (only for 18650's & a maxamps 1850mah 3s lipo)


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## Gauss163 (May 30, 2016)

sdmf74 said:


> No, will that give me innacurrate readings of my batteries total mah when doing a discharge/charge test???



You can guesstimate the difference by looking at these discharge curves. They imply that the typical capacity between 3.1V and 2.8V is about 1-3% at 1A discharge, and about double that at 3A. These numbers will vary a bit depending on chemistry, IR, etc, but are probably reasonable ballpark estimates. You also need to factor in the effect that the charger measures voltage in-between current pulses, which will skew the numbers a bit. You'll need to runs some tests to get accurate numbers.


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## filibuster (May 31, 2016)

HKJ said:


> It is a good option, but may not always charger at full speed, due to problems with the usb power.


Is it however, one of the most efficient chargers you've tested using the least amount of power to charge two or four cells?


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## sdmf74 (May 31, 2016)

TinderBox (UK) said:


> sdmf74 you do realise that firmware v3.1 discharges Li-ion to 3.1v when v2.2 discharges to 2.8v
> 
> John



John you said this as if its a bad thing, unless I took it the wrong way. What are the disadvantages if any to discharging to 3.1 instead of 2,8v?


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## TinderBox (UK) (May 31, 2016)

According to what i have read from other CPF members, li-ion data sheets give capacity ratings based in discharging to 2.8v not 3.1v so as other members have mentioned above you will have to guesstimate what the 2.8v capacity would have been, the only affects you really if you decide to do a capacity check on some li-ion cells and want to share the result, just mention that the results are from discharging to 3.1v instead on 2.8v

It was also mentioned above this 3.1v discharge level was so that some protected li-ion cells protection circuit do trip when they go under 3.0v the only protected cells i have do not trip till the voltage hits 2.5v i suppose the manufacture can set whatever protection voltage level they like.

Does the VC4 have a way of resetting tripped protection circuits, anyway i though you should be aware of this new firmwares features.

John.



sdmf74 said:


> John you said this as if its a bad thing, unless I took it the wrong way. What are the disadvantages if any to discharging to 3.1 instead of 2,8v?


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## sdmf74 (Jun 1, 2016)

Thanks for clearing that up for me.

After further thought I think I will opt for the V2.2 for more accurate comparisons. I never buy protected Li-ion cells anyway so the adjustment in v3.1 wouldnt pertain to me anyway.


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## ChrisGarrett (Jun 1, 2016)

sdmf74 said:


> Thanks for clearing that up for me.
> 
> After further thought I think I will opt for the V2.2 for more accurate comparisons. I never buy protected Li-ion cells anyway so the adjustment in v3.1 wouldnt pertain to me anyway.



I got my v. 2.2 right before the v. 3.1 started becoming available, but I think I would still choose the 2.80v cutoff found in v. 2.2.

Just going on memory (and it's different for different makes and models,) but most of the Big 5 cutoff at 2.50v and/or 2.75v (Samsung IIRC) for their datasheets and while I wouldn't necessarily want to discharge down to 2.50v for a few extra mAh on my display, I'd rather do 2.80v vs. 3.10v, although current is eeking out at that voltage level and unless you're doing vampire lights, what's the real point?

Anyhow, 3.1v vs. 2.8v, we have more important things to worry about, but this is one instance where I'm glad that I missed the 'upgraded' model before buying.

Chris


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## Gauss163 (Jun 1, 2016)

TinderBox (UK) said:


> It was also mentioned above this 3.1v discharge level was so that some protected li-ion cells protection circuit do trip when they go under 3.0v the only protected cells i have do not trip till the voltage hits 2.5v i suppose the manufacture can set whatever protection voltage level they like.



The problem is not that the undervoltage protection on the cell is set too high. Rather, the problem is caused by the combination of the C3100's pulsed discharging and old cells with high IR = Internal Resistance. The PWM _pulses_ have higher current than the equivalent _CC = constant _current discharge, so the pulses will cause a deeper IR voltage sag. With very high IR, the voltage sag may be so deep that it trips the undervoltage protection. But the CC sags are not as deep so they don't trip it. So Opus had to bump up the discharge termination voltage to avoid false trips cased by these deeper pulsed sags. 

Also playing a role is that the Opus measures voltage with the current off, unlike CC (dis)chargers. Generally it is an apples vs oranges comparison when comparing a PWM vs CC discharge because they are using different types of loads, which also affects the meaning of the termination current. But generally they should still be close, except in some exceptional contexts.


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## TinderBox (UK) (Jun 1, 2016)

*Gauss163 I have asked you not to reply to me, I am adding you to my ignore list*, Sorry only kidding :laughing: thanks for the information.

John.



Gauss163 said:


> The problem is not that the undervoltage protection on the cell is set too high. Rather, the problem is caused by the combination of the C3100's pulsed discharging and old cells with high IR = Internal Resistance. The PWM _pulses_ have higher current than the equivalent _CC = constant _current discharge, so the pulses will cause a deeper IR voltage sag. With very high IR, the voltage sag may be so deep that it trips the undervoltage protection. But the CC sags are not as deep so they don't trip it. So Opus had to bump up the discharge termination voltage to avoid trips cased by these deeper PWM sags.


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## Aquassey (Jun 24, 2016)

Ooops. Duplicate


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## Aquassey (Jun 24, 2016)

Your "Supported Battery Sizes" chart doesn't show the 32650, even though the VC4 packaging and manual do include it. Just an omission?


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## HKJ (Jun 25, 2016)

Aquassey said:


> Your "Supported Battery Sizes" chart doesn't show the 32650, even though the VC4 packaging and manual do include it. Just an omission?




Thanks, I have fixed the table.


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## Andrew LB (Jun 25, 2016)

I was on the fence when i first started writing this a few hours ago and was deciding between the Xtar VC4, VP4 and Opus BT-C3100 v2.2. I currently have a Nitecore D4 that bought in October, 2014 that just had channels 1 and 3 crap out. Then to add insult to injury, it seems my charger is fake (doesn't say Nitecore on the AC input port) according to another thread i just read. The charger is used primarily for Samsung INR18650-25R cells (at least these are legit) that i use in my flashlights and for vaping. 
I ended up ordering an Xtar VC4 and since they stupidly didn't include an AC adapter, i also purchased an Anker 24w 4.8a dual USB adapter which i'm hoping will work properly. I just noticed that Xtar Direct is located literally 5 minutes away from my house, so if the adapter i ordered has issues, ill just drive to Xtar and get their adapter. The charger should be arriving by the end of the day today, so ill let you all know how i like it then.


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## mightysparrow (Oct 2, 2016)

HKJ: thanks very much for this review - very helpful to me! :thumbsup:


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## mightysparrow (Oct 8, 2016)

My VC4 (brand new) does not appear to be showing me the actual capacity of my XTAR 16340 cells at the end of charging, as the instructions say it should. What is wrong? It is showing about 220 mAh, which is not the total actual mAh in the cells, I hope!

I also notice that my USB hub that is rated at 5V and 3100 mA is not powering the charger - so it appears that it is not as capable as the manufacturer claims. Am I right? Even my HP Pavilion Elite 9280t desktop computer is not giving me the full 500mA charging rate it should on my 16340 cells. I am using a cheap wall outlet adapter that works well to give me the full 500mA charge.


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## HKJ (Oct 8, 2016)

mightysparrow said:


> My VC4 (brand new) does not appear to be showing me the actual capacity of my XTAR 16340 cells at the end of charging, as the instructions say it should. What is wrong? It is showing about 220 mAh, which is not the total actual mAh in the cells, I hope!



Did you run the battery dry before charging it? It works like a gas tank, if there is something in it you can not see the full capacity when filling it.
Also note that old batteries will loose capacity.



mightysparrow said:


> I also notice that my USB hub that is rated at 5V and 3100 mA is not powering the charger - so it appears that it is not as capable as the manufacturer claims. Am I right? Even my HP Pavilion Elite 9280t desktop computer is not giving me the full 500mA charging rate it should on my 16340 cells. I am using a cheap wall outlet adapter that works well to give me the full 500mA charge.



The charger checks on the usb voltage, if it is low it will reduce charge current, some reasons it can be low:
Weak usb charger
Usb charger/laptop has a low output voltage from the start
Long cable
Unpowered usb hubs


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## mightysparrow (Oct 8, 2016)

HKJ said:


> Did you run the battery dry before charging it? It works like a gas tank, if there is something in it you can not see the full capacity when filling it.
> Also note that old batteries will loose capacity.
> 
> 
> ...



HKJ: thanks very much for your prompt response to my post. I should not miss the "total charge capacity" information too much, if I know that the voltage at the end of charging is at the full 4.2 level. I guess I'll generally get some idea of the total capacity of the cells as I use them. 

The charger appears to work well otherwise, is easy to use, has attractive and easy to read charging current and voltage readouts, and is quiet and feels solid. 

The cells I charged last night are XTAR 16340 cells. I will now charge some new AW 16340s and see how the charger works with those. Thanks again for your excellent review of the product (which was extremely helpful in aiding my decision to seriously consider purchasing the product) and for your response to my post today.


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## HKJ (Oct 8, 2016)

mightysparrow said:


> HKJ: thanks very much for your prompt response to my post. I am quite surprised and somewhat disappointed that the instructions for the product promise a benefit that is not in fact provided - the total charge in the cell at the end of charging. On the other hand, I should not miss that information too much, if I know that the voltage at the end of charging is at the full 4.2 level. I guess I'll generally get some idea of the total capacity of the cells as I use them.



I will not comment on how Xtar explains stuff, but you can measure the full capacity of your batteries by running them empty first (Do not over discharge the batteries).

With LiIon the charged capacity is about the same as the discharge capacity, that is not always the case with NiMH.


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## mightysparrow (Oct 8, 2016)

HKJ said:


> I will not comment on how Xtar explains stuff, but you can measure the full capacity of your batteries by running them empty first (Do not over discharge the batteries).
> 
> With LiIon the charged capacity is about the same as the discharge capacity, that is not always the case with NiMH.



Thanks, HKJ - I had no idea that charged capacity would be about equal to discharge capacity, even with overdischarge protection working and quite a bit of voltage left in the cells. Thanks for education.

Looking at the instructions carefully, I notice they include the phrase "*at a discharge cutoff voltage generally below 3.0 V*" in the discussion of how to get a readout of the total amount of charge capacity in the fully-charged cell. I am guessing this means that the full cell capacity will be shown on the display after charging only when the initial voltage before charging is below 3.0 V. I will have to presume for now that this in fact is the case.


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## Minimoog (Nov 22, 2016)

I think that this is an excellent charger which is hobbled by the 5 Volt input. I bought one late last year but despite buying a few USB adaptors including the 2.4 Amp model from the Apple store I kept getting low charge current and flickering display during charge pulses. I did some research at our laboratory and noted that all my USB adaptors didn't like a pulsed load as occasionally the output dropped to around the 4.8 Volt mark and that then made the VC4 see a weak supply and drop the charge current. I ended up making my own supply using a 40 Amp capable MeanWell caged PSU run into a heatsunk buck converter. Over $200 of external parts (thankfully that I was given) now gives me perfect charge and steady display. I now get some really well charged batteries which shows that the charger is a good design, just unduly hobbled by reliance on junk supply voltage from unstable wall warts.


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## CelticCross74 (Nov 27, 2016)

Had my VC4 for over a year now and it still works perfectly. I ditched the Xtar specific wall wart for the Verizon iPhone 6 upgrade wall wart. I do not know the specifics of this wall wart I just can tell you it is Verizon labeled, black and has a red LED ring around the front of it that lights up when a USB device is plugged into it. With this wall wart my VC4 will not drop charge current at all no matter what I load into the VC4. With all 4 slots loaded with any cell size and type it is pegged at .50 amps never dropping charge current at all. With the 1 amp slots only loaded up with any size or chem type cell it is pegged at a full amp never dropping charge current. I like it so much I bought another VC4 and another Verizon iPhone 6 wall wart. They are awesome.


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## Woods Walker (Nov 28, 2016)

*Final conclusion must be that it is a good charger.*

The last line says it all. So far mine has been working just fine. I use the USB plug from my Ipad Air 2. Seems to operate just fine with it.


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## gsgtsg (Jan 27, 2017)

Hi,

I am charging a set of AA Ni-MH batteries and one is saying '0V NULL' on the display.

Does this mean the battery is faulty and cannot be recovered?

Thank you.


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## ssanasisredna (Feb 25, 2017)

Wowsers! What a phenomenal review!

I needed to get a charger quick ... saw this on Amazon, came here to see if anyone reviewed and what do I find!

Thank You HKJ!


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## ChrisGarrett (Feb 25, 2017)

gsgtsg said:


> Hi,
> 
> I am charging a set of AA Ni-MH batteries and one is saying '0V NULL' on the display.
> 
> ...



It could be that it's a bad battery, or just a battery that is too low to charge on the VC4. What voltage are you getting with a digital multi meter? Some chargers won't charge up a battery/cell below a certain voltage.

If you have a dumb, timed charger, you can put the battery in that for 15-30 minutes, let it charge up a bit...say to 1.00v and then put it back on the VC4.

Chris


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## samfeee (Apr 14, 2017)

can i charge ni-cd with this charger ?
is there another revision of XTAR VC4 on market ? i see two package one yellow other one white:
http://www.xtar.cc/products_detail/productId=64.html


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## samfeee (Apr 14, 2017)

can i use this to charge NI-CD battery?
is there another revision of this charger ?
i see to package one yellow box another white box
http://www.xtar.cc/products_detail/productId=64.html


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## HKJ (Apr 14, 2017)

I can see you post got approved.

NiMH and NiCD can both be charged with a NIMH charger, but a NiCD charge can only charge NiCD.

My graphic was faulty and I have corrected it (Thank you).

Xtar changed their color scheme recently, that means all current products got a new package.


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## samfeee (Apr 22, 2017)

HKJ said:


> I can see you post got approved.
> 
> NiMH and NiCD can both be charged with a NIMH charger, but a NiCD charge can only charge NiCD.
> 
> ...



tanx bro i got my order there is only one version with new packaging 
on the back of the package wrote you can charge ni-cd


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## vadimax (Apr 30, 2017)

Fake or not fake -- this is the question... I have ordered this one: http://www.ebay.com/itm/182529009023?_trksid=p2057872.m2749.l2648&ssPageName=STRK:MEBIDX:IT, but I don't see authenticity label on the bottom wall and its price is half of the normal one. Makes me suspicious


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## vadimax (Apr 30, 2017)

Deleted. That was a posting malfunction right before the forum stop.


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## Mr Baz (Apr 30, 2017)

vadimax said:


> Fake or not fake -- this is the question... I have ordered this one: http://www.ebay.com/itm/182529009023?_trksid=p2057872.m2749.l2648&ssPageName=STRK:MEBIDX:IT, but I don't see authenticity label on the bottom wall and its price is half of the normal one. Makes me suspicious


 
The old version ie box came with the sticker on the charger all the 10 year Xtar ones I've tested have a separate card inside with the verification code on that. I wouldn't be suspicious unless that card isn't included


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## vadimax (May 1, 2017)

Mr Baz said:


> The old version ie box came with the sticker on the charger all the 10 year Xtar ones I've tested have a separate card inside with the verification code on that. I wouldn't be suspicious unless that card isn't included



Thank you so much  You've calmed me down a bit.


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## Weylan (Oct 20, 2017)

Looking to use the XTAR VC4, with a 6V solar panel and 4XD batteries. Will the VC4 handle the input range of 4.8V-6V?


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## filibuster (Oct 20, 2017)

Weylan said:


> Looking to use the XTAR VC4, with a 6V solar panel and 4XD batteries. Will the VC4 handle the input range of 4.8V-6V?


How many watts is the panel?

The VC4 seems to do well at 5.25 to 5.5 volts so it's not too much of a stretch to get to 6v. The question is however, is your solar panel truly going no higher than 6v?

You may need to consider a USB Voltage Regulator Module to help hold the voltage at USB specs.

On a side note concerning D cell batteries, the VC4 will only fit and charge 2xD at a time in the outside slots. The two inner slots won't hold D cells.


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## Weylan (Oct 20, 2017)

Sorry what I mean to do is use solar panel to charge 4xd batteries as buffer. And tap off of that. So the input is solar panel at 5-6V but that feeds into the D batteries as a buffer. The solar panel i use usually is a nice 10W and 7W and I hate clouds making the charger stop. So I usually use the 4x D cells as a buffer and let the D cells get what we can from the solar panel, and then use what I want from the D cells. Generally the 4xD cells stay about 4.8-6V. Which is usually where we want to be for 5V usb devices.

I often car camp with family and we use 20aH battery banks for iPads and this method charges the battery banks just fine but I wanted a way to charge headlight batteries of 18650 and AAs.

And the VC4 looked like a great candidate.


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## Grijon (Feb 11, 2018)

Hello all,

I would like to suggest that the original review (Post #1) make some mention of the VC4's common inability to provide 1A to two cells at a time regardless of the power supply used.

HKJ does an excellent job with his reviews; I appreciate, trust and use them any time I'm thinking about a charger or battery purchase.

I purchased a VC4 after reading the initial review, with the bottom line that this is a good charger. I have only ever used the cable it came with. It didn't take long for me to discover that an Apple iPad wall wart wasn't enough to provide full charging ability to the charger, so I bought an even higher-powered wall wart. It, too, is frequently unable to allow 2 18650s in Channels 1 & 4 to charge at 1A, despite having plenty of power on paper.

So I did what I should have done in the first place and read deeper into this thread, where I see that I am not alone in this. I fully admit that had I read further than the initial post -the proper review- that I would have seen the problems, but I didn't and perhaps other potential purchasers won't either; the reason that I read only HKJ's post was that I trust him totally and thought that any problems would be explained in the review.

*Please understand that I'm not faulting HKJ or his review in any way, but rather trying to help it in its purpose of informing potential buyers about the product before they make a purchase.*

As always, thank you HKJ, for all the work you do for the community!


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## Gauss163 (Feb 11, 2018)

^^^ By now there are so many analyzing chargers with so many features that there is significant combinatorial complexity involved in making informed buying decisions. It would be very helpful if - like HKJ's battery comparator - we also had a charger comparator. 

For example, this could allow prospective buyers to choose those options (rows) they wish to compare in a spreadsheet - which would make it easier to spot limitations such as that mentioned above.


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## HKJ (Feb 11, 2018)

I did write something about the charger being sensitive to the supply voltage and I did also do at test at 5.2volt (When I do this the charger is usual very sensitive to voltage).

I do have some sort of comparator for the chargers: http://lygte-info.dk/info/roundCellChargerIndex UK.html
It do not have that many parameters included (The analyzer and usb output tables have an extra parameter).


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## Nev (Feb 11, 2018)

Grijon said:


> Hello all,
> 
> I would like to suggest that the original review (Post #1) make some mention of the VC4's common inability to provide 1A to two cells at a time regardless of the power supply used.
> 
> ...



Check your iPad charger , because my vc4 charges 2 x18650 at 1amp & 4 x 18650 at .5 amps.


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## vadimax (Feb 12, 2018)

May that be particular charger sample issue? Mine functions in accordance with its specification with Apple iPad wall charger (rated 2.4A). The only drawback — the poor adapter becomes rather warm under load (VC4 just cannot be 100% efficient, so it pulls more than 2A). So I purchased a more powerful USB charger to mitigate that heating issue.


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## alkin (Mar 25, 2018)

Hi folks, 

I own two Sony CycleEnergy 2100 mAh AA size batteries, and they still perform well after 7 or 8 years. 


The past week I purchased an Xtar VC4 and charged these two batteries simultaneously (in slots number 1 and 2). One of them got 3400+ mAh of charge (under 0.5 amp. through my laptop’s USB) and the other got 4300+ mAh of charge (and took around 2 hours longer).



Now, is that normal? The batteries are 2100 mAh max, do you think that the charger must have a defect?


Thanks
Alkin


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## ChrisGarrett (Mar 25, 2018)

alkin said:


> Hi folks,
> 
> I own two Sony CycleEnergy 2100 mAh AA size batteries, and they still perform well after 7 or 8 years.
> 
> ...



I've had a VC4 for a few years and used it over at my GF's place two weeks back. My misses termination quite a bit and did so then, so I just removed the longest charging cells and live with it.

It's probably trickle (low) charging them up and you got more input, much like the vaunted Maha C9000 low charges batteries during the break-in phase--1/10th of rated capacity for 16 hours.

If I ever have a kid, I'm going to name it Xtar, so I'm a fan-boy, owning 10-12 of them, but I never liked the VC4 much for the above reason. It's a 4 bay USB charger that I can use with my USB solar panel and even my 12vdc mother batteries, in a pinch, but it's not my every day charger--hence the reason I leave it at my girlfriend's place.

Chris


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## sbj (Mar 25, 2018)

The charger probably did not recognize the Delta Peak.
I would select at the next charging 1,0A charge current.


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## ChrisGarrett (Mar 25, 2018)

sbj said:


> The charger probably did not recognize the Delta Peak.
> I would select at the next charging 1,0A charge current.



Not when you're charging up 4 slots. 2 slots...sure. There are no manual charge rate settings on the Xtar VC4.

Chris


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## Grijon (Nov 9, 2018)

Update: I now think that my VC4 is defective as it's having a terrible time charging my Fenix 16340s. After reading all the problems other users have had with theirs, I won't be buying another. I am very disappointed.


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## Minimoog (Nov 11, 2018)

I use one of these still, but got so fed up with the supplies not being up to the task I made my own with a 100 Watt rating. Now the charger works fine and no missed terminations or pulsing display. However I will never again buy such a USB powered charger. Just not enough power to do the job right.


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## tgo (Nov 13, 2019)

I've just ordered this, but didn't catch if it would charge unprotected (flat top) 18650's

Does it?


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## jm79 (Oct 14, 2021)

Good day, would be getting a charger for my unprotected samsung 30Q 18650s and AAA, AA batteries. Not a techie guy that much so I prefer and plug and play type that can charge my batteries with overcharging and safety protection. And also that will automatically charge them with correct voltage, etc. Mains are a plus. Any suggestion about the following and best of all I have chose regardless of price? 

Nitecore D4/I4
Xtar VC4/X4
Liitokala Engineer Lii500

Thank you.


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