A123 charging problem

[jhautz]

Did you run them totally dead. Even though a123 are resistant to abuse you still cant just run them totally dead until the truck just stops. They have a minimum voltage of 2v/cell and running them down below that is not healthy for them.

Fortunately you can probably save them because they are such resilient cells. Set your charger to NiMH and a very low current setting like 0.5 amps and hook the pack to the charger for just a few minutes so you can raise them above 4v. then stop the charge and set the charger to a proper a123 charge cycle, but if you can set the current very low (like 0.5v again) and charge them like that. You should be able to get them back up to full voltage but it will take a few hours to get them there.

Be careful when doing this initial bump charge with the NiMH setting and don't forget and leave them on there. It shouldn't take much at all to bump them back over the 4v minimum so your charger will recognize them properly.

Once you start feeling the power drop off noticeably stop running them. Discharging them to that low repeatedly will certainly effect the life of the cells.