Battery ?

[Igoreski]

I was checking some of my battery packs in cold storage[fridge] and my oldest Turnigy 4500mah 3s 30c packs was down to 3.1v in 1 cell and all the rest were 3.8v which is where my charger stores them at.I am having a problem balancing the pack and it is still off by .3 and I checked it on another charger,same thing.Is this pack toast or is there a charge discharge cycle that might bring it back to life.

[Fluid]

Charge the pack - while watching closely - until the highest cell voltage is 4.15 volts. You will need a cell reader for this, but you should have one anyway. Put on a balancer and let it do it's thing. You may have to repeat a few times; if it doesn't return to all cells with matching voltages, then toss the pack.

This is not uncommon with cheap cells, although it can happen to any pack.

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[johnnyoverkill]

As a side note, do not charge them cold! Warm them first with warm air from a hair dryer, heating pad on low, etc. There are several members here that posted their favorite way of doing this. It excites the chemicals in the cells and provides for a higher output.

Good luck,
John

[Igoreski]

I was discharging them on a storage cycle at 0.5a and the pack puffed on one side.I plugged it into an old 775 motor direct,duct taped them together and threw it in a bucket of water.It ran for 10 min like a hot tub motor and now is slowly discharging on the patio bricks.The side that was puffing is now bigger.

[m4a1usr]

You can always make that 3S pack into a 2S. No need to toss the entire pack due to one bad cell. It does require you to buy the materials needed for pack modifications but heck,........if your going to hang with this hobby you will need to be a garage mechanic anyways. Dont throw away what could be made to work.

John

[Fluid]

As a side note, do not charge them cold! Warm them first with warm air from a hair dryer, heating pad on low, etc. There are several members here that posted their favorite way of doing this. It excites the chemicals in the cells and provides for a higher output

Not quite right. With the older chemistry LiPos, heating them before running them (not before charging) would increase the voltage output by reducing internal resistance. We used to see FE boats get faster during a run as the packs heated up, but today this is not nearly as noticeable. Datalogging my current 45C cells indicates no increase in voltage as the packs heat up. Still, running cold packs is not a good idea.

LiPos should be charged at ambient temperature, not heated (although on a 105* day they are warm).


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