Homemade Batterry Packs - Rebuild
I decided to rebuild all my 2008 era "homemade" 18650 packs.
Most have been sitting a couple years.
I noticed a bad "balance" on my 37V 20.8Ah build.
So I have decided to rebuild my 3 - 37V 20.8Ah and 2 - 25.9V 31.2Ah packs, a total of 408 18650 cells.
I still have another 100+, unused cells.
1. Disassembly of hundreds of solder connections
2. Charge all cells to 4.2V
After I disassemble all packs, I will gang together 1s40p cells and charge with my modded MeanWell S-150-5 @ 4.2V 30A. (Note: recycled Lipo cells will be tested at a modest 4.1V per cell, but monitored for self-discharge for a considerably longer time period, several days, a week?)
3. Test all cells
a. After fully charging, separate, let set ~24 hours, any noticeable self-discharging cells will be eliminated. (Degree, and depth, of self-discharge has proven to be a reasonably reliable "yardstick" of cell condition!)
b. Apply a .5C, timed, drain to each cell, low ending voltages will be eliminated.
4. Build packs
I intend on a modular construction.
3s8P 11.1V (12.6 fully charged) 20.8Ah modules
(I plan on using 25.2V*, 37.8V*, 50.4V* builds)
I will install balance plugs, but after thorough testing I intend on bulk charging ... with scheduled balance charges.
5. The builds (eZip pack capable)
a. 22.2V - 6s16p 96 cells 22.2V 41.6Ah 923.5mAh
b. 33.3V - 9s8p 72 cells 33.3V 20.8AH 692.64mAh +9s1p 5700mah RC Lipo 5.7AH 189.81MaH = 26.5AH 882.45MaH total - Hybrid Pack
c. 44.4V - 12s8p 96 cells 44.4V 20.8Ah 923.5mAh
6. I intend to streamline pack build using flat tinned 9-10ga copper braid, replacing 10ga insulated stranded copper. 22ga tinned copper wire for balancing.
* Fully charged
Any cells not rated as grade A, but reasonably good, will probably be allocated to other applications such as:
Lanterns - florescent, LED etc.
Power inverter - pulled 36Ah SLA out of a 200watt pack, could pack in 11.1V ... 100Ah Li-ion?