Alien aurora battery out of balance?

[gavztheouch]

I am getting about 2 miles or so range out of my alien with the current battery. I am the third owner and don't know the bikes history.

I decided to open the battery pack today after it had been discharging on the shelf for a couple of months here are the voltage readings on the 37v 10 cell pack

Pre-charging

4.04
3.60
4.01
4.02
3.78
4.02
4.02
3.96
3.93
2.99


Post charge

4.18
3.84
4.08
4.12
3.88
4.10
4.13
4.00
4.00
3.70

So it looks like at least 3 cells are sitting at a much lower voltage than the rest of the pack. Is there anything I can do to help bring them back into balance. I noticed as it was charging the weak cell were taking a consistant charge and rising steady until the charger turned green and stopped the charge. I have always turned the charger off within an hour of it turning green. I heard leaving it on over night can help balance the pack?

Cheers
Gav

 

[Deleted member 4366]

It's probably completely sh@gged. Does it have those prismatic cells about half inch thick?

Balancing might restore a bit of capacity, but the question is: why is it so unbalanced? Re-balancing would be dead easy with a BC168 charger, which can do six cells at a time, or these can do three cells at a time:
http://www.ebay.co.uk/itm/High-Quality-B3-7-4V-11-1V-2S-3S-LiPo-Battery-Balance-Charger-for-RC-Helicopter-/290979591863?pt=UK_ToysGames_RadioControlled_JN&hash=item43bfbc36b7
You need one of these too:
http://www.ebay.co.uk/itm/10pcs-JST-XH-3S-Lipo-Balance-Wire-Extension-Lead-22cm-for-Dualsky-Align-RC-Helic-/400553468545?pt=UK_ToysGames_RadioControlled_JN&hash=item5d42d8e281
If you carefully cut the plastic off from around the pins on the female end, you can plug it straight in to your cell-pack multi-pin connector, but you must get it the right way round.

Another thing you can do is use a 3v torch bulb to drain down the high cells. The high ones prevent charging, and the low ones prevent discharging.

 

[gavztheouch]

Thanks D8veh, can I just put a bulb across a cell without disconnecting all the metal tabs that link the cells in series?

I have just read another thread on a similer topic and you suggested using a 5v phone charger to bring up the weaker cells. Should I connect positive to positive with the charger and battery.

I have some photos of the cells I will post tomorrow. They are about an inch thick with a small vent near the poles. The terminals are rusty and the battery weather proofing seal looks like it may be bust. I guess some water may have made its way in.

 

[Deleted member 4366]

Every battery that I've tested with those cells (all old), every cell was scrap. They normally balance well, but have no capacity.

You can connect the torch bulb either way round to the cell poles. The phone charger has to go plus to plus. If you get it wrong, it might pop, so use an old one that you don't need.