How many cycles does it take for a lithium battery, that has been recovered from a severely overdischarged state, in which it had been for a very long time, to recover to its full remaining capacity?
The place where i interned let me have a dead battery pack from one of their segway thingies. The pack has 64 SONY US18650V3 cells, of which 16 were immediately either shorted or open.
The specs for the cells are dated but beggars can't be choosers, right?
Anyways, after recovering the cells with the help of a 5V PSU and a 150 Ohm resistor i plug them into my Lii-500 battery charger to test them and the first 4 came out at a pretty healthy 2030-2098 mAh, which is pretty good for a cell that sat at some 1V for what might be over a year. I hadn't used the charger for a while so before i figured it out i put two cycles on the cells.
The next two, however, came out at a much lower 1900 and 1847 mAh and that makes me wonder, will the capacity go up if i cycle the cells since these are only on their first cycle after recovery?
It's important to know because if i want to assemble a pack out of these i need to balance the capacity of each set of parallel cells and if they're not yet fully recovered that will become a problem once the pack is cycled a few times.
What do you guys think?
Also a tip for your Lii-500: You can make the normal test as fast as the fast test if the cells are precharged. I use my spare TP4056 modules to precharge the cells before they go into the tester.