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Help! Can't charge my Lipo

RC6-VSR displaying cell voltage error

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David Ramsden09/07/2020 21:42:08
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27 forum posts
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Frustrated beginner. Bought my first Lipo (overlander 2900mah 11.1v 3s) and my first charger (overlander RC6-VSR). Every time I try to start charging the display shows Cell Voltage Error. I have set the correct voltage for the cell type (3.7) and the pack (11.1) and I set the charge rate to 2A.
I think the problem is that the charger is only detecting two cells (2s). I have increased the check time (CHK time) from ten to 15 mins (to give the charger more time to detect the cells) but it still gives the error message. Help!
Thanks.

Ben B09/07/2020 22:08:12
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1435 forum posts
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Plugged in the balance lead?

Ben B09/07/2020 22:12:44
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1435 forum posts
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Can you measure the total pack voltage when off the charger (would require a multimeter). Or possibly check the individual cell voltages through the balance lead.

David Ramsden09/07/2020 23:05:21
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27 forum posts
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Hi Ben. Yes the balance lead was plugged in. Pack voltage off charger is reading 10.7v. Not sure how to check the cells. The balance lead has a black a red and two whites.

David Ramsden09/07/2020 23:16:16
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27 forum posts
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Checked the voltage again. It now says 11.31?? My multimeter is normally reliable. I assumed it was low because the motor runs for a few seconds then stops, but surely at anything above about 10.5 (3x3.5) the motor should run?? and the battery should charge??

Denis Watkins09/07/2020 23:36:28
4536 forum posts
123 photos

Will the servos move to?

Is it just the motor not moving,

Phil Green09/07/2020 23:49:58
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1612 forum posts
342 photos

Silly question, you do have the power connector plugged in as well as the balance plug?

Also, on your charger, you said that you'd set the volts per cell to 3.7v.

Just check that there isnt a 4.2v setting, and 12.6 for the pack.

If so, those are the correct settings.

Edited By Phil Green on 10/07/2020 00:04:25

David Ramsden10/07/2020 00:29:37
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27 forum posts
13 photos

Hi Denis. Yes the BEC supply is fine. The servos work. The motor runs for a few seconds then stops.
Hi Phil. Yes, I have the Deans connector plugged in as well as the balance plug. There may be a 4.2/12.6 setting on the charger (not checked) but surely 3.7/11.1 are the right settings(?).

I have since tried the charger with a 1600mah 3s pack and it;s charging fine so it seems that the 2900mah pack is faulty. How likely is that? It's brand new.

Phil Green10/07/2020 00:35:16
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1612 forum posts
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Some charger menus specify peak voltage, not nominal, so the settings for a 3S lipo are 4.2 and 12.6v.
Maybe yours does - your cells are over 3.7 presently, hence you charger gives the cell voltage error. The 3.7 setting would be the peak voltage for LiFePo4 chemistry.

So maybe you've told the charger to expect a LiFePo4 but connected a LiPo.

 

 

Edited By Phil Green on 12/07/2020 00:37:34

David Ramsden10/07/2020 00:51:01
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27 forum posts
13 photos

Thanks Phil. The 1600mah pack has just finished charging (on the 3.7/11/1 settings) to 12.6v no probs.

I tried to increase the settings to 4.2 and 12.6 but those figures are not available on this charger so 3.7/11.1 must be right(?). I tried the 2900mah battery again and it still says "Cell Voltage Error".

Richard Wills 210/07/2020 02:19:01
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208 forum posts
7 photos

You can measure the individual cell voltages from the balance connector with your multimeter if you are very careful. Measure across pins 1 and 2, then 2 and 3, and finally 3 and 4. Knowing this will tell you much more about the pack.

Edited By Richard Wills 2 on 10/07/2020 02:20:43

Nigel R10/07/2020 08:49:56
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3981 forum posts
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"How likely is that? It's brand new"

Somewhat likely. If the charger works with a different 3S pack then I would consider simply returning it to Overlander; you pay Overlander prices to get their customer service. It sounds to me like you may have a faulty balance cable. If you measure as per Richard's post, that will tell you a lot.

"so 3.7/11.1 must be right(?)"

The Overlander charger shows the nominal voltage for the chosen cell chemistry - so 3.7V is the right option for a normal lipo. If LiFe was selected it would show 3.3V, for LiIon, 3.6V, and I think it does HV cells with a reading of 3.8V.

John Lee10/07/2020 09:19:32
764 forum posts
86 photos
Posted by Phil Green on 10/07/2020 00:35:16:

Most charger menus specify peak voltage, not nominal. If your is like every one I've seen, used or repaired then the settings for a 3S lipo are 4.2 and 12.6v.

Your cells are over 3.7 presently, hence you charger gives the cell voltage error. The 3.7 setting is the peak voltage for LiFePo4 chemistry.

In a nutshell you've told the charger to expect a LiFePo4 but connected a LiPo.

Edited By Phil Green on 10/07/2020 00:44:31

I was also suspicious of the quoted 3.7v but it is correct. I looked up the Manual & in Section 5 it says:

overlander charger.jpg

as Nigel says, don't mess about, return the battery.

David Ramsden10/07/2020 10:31:43
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27 forum posts
13 photos

Thanks Richard Nigel and John.
I measured the cell voltages as you suggested Richard and they are 5.26v, 5.65v, and 0.41v.

I have contacted the Ebay seller [who has 100% positive feedback (so far!)]. They say I might be able to rectify the problem with my charger but I am doubtful.

Thanks again. David

PS Adam at wireless-madness talked me through a procedure which seems to have worked. This involved telling the charger it was a completely different type of battery(!!). Now it has started doing a Lipo balance charge.

Edited By David Ramsden on 10/07/2020 11:24:18

Simon Chaddock10/07/2020 10:41:52
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5733 forum posts
3034 photos

David

If one cell is reading 0.41 V then what your charger is telling you is quite correct - there is a cell voltage error. wink 2

0.41 V is NOT a recoverable voltage for a LiPo cell. If that reading is correct the pack is faulty. The only remedy is to seek a replacement or refund.

Nigel R10/07/2020 10:43:04
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3981 forum posts
714 photos

I don't think you have a problem with your charger.

If that lipo is truly measuring 5.26V, 5.65V and 0.41V, you need to discharge it ASAP and throw it, it is toast, and I'm surprised the two 5V+ cells are still physically in one piece at that high voltage level. It is certain to be permanently and badly damaged, no chance of salvage.

Did you buy this stuff second hand?

Edited By Nigel R on 10/07/2020 10:43:57

Denis Watkins10/07/2020 10:48:06
4536 forum posts
123 photos

The charger proved absolutely right David

With" Cell Voltage Error "

Follow Nigels advice, I would not even risk the health of the return carrier with that pack.

Edited By Denis Watkins on 10/07/2020 10:48:55

David Ramsden10/07/2020 12:01:30
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27 forum posts
13 photos

Hear what you are saying Simon, Nigel, and Denis. Thanks.

Despite the fact that the pack is now doing a balance charge, I have told Wireless-Madness that I reserve the right to seek a replacement or full refund. If indeed the pack is permanently damaged, how would I know????

Dickw10/07/2020 12:26:55
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736 forum posts
99 photos
Posted by David Ramsden on 10/07/2020 12:01:30:.............If indeed the pack is permanently damaged, how would I know????

How did you fix it so that it will now do a balance charge?

Once fully charged, discharge it via your charger to see what capacity you get, and what the voltages look like.

If the voltages you stated earlier were correct then I would already regard it as "permanently damaged".

Dick

Piers Bowlan10/07/2020 12:32:16
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2167 forum posts
53 photos

If any one cell drops below 2.8v the whole battery is finished as far as I am concerned. .41v is completely dead and it will never recover or support any useful load. Get your money back if you can. Also be very careful trying to charge a defective battery as that is how fires can start.

Also this sort of thing can be very useful for checking cell and battery voltages and capacity.

Edited By Piers Bowlan on 10/07/2020 12:38:38

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