dopravopat
New member
- Joined
- Feb 25, 2019
- Messages
- 4
Hello!
I would like to build a 10S7P battery pack for my e-bike. I harvested many cells from old notebook batteries. I picked identical Samsung ICR 18650-28A cells for the battery, I do not want to mix different brands and types.
I measured each cells capacity,charged themto 4,2Vand let sit forabout 8 weeks.Today Imeasured the voltage. The results are in the attached file asmAh;voltage.
My question is how to best match these cells to a 10S7P configuration.
Should Ibuild each 7P module with batteries that have capacities as close as possible and as a result have ten modules with bigger difference in overall capacity, or mix cells so that all modules have similar total capacities and each module will consist of mixed capacity cells? Matching voltage is more of a theoretical question, as the differences are very low, basically between 4,17V and 4,19V, with only two cells at 4,16V (as you might have noted, I posted the results for 73 cells, I need only 70 in my battery, so 3 cells are extra).
How would you match the cells for the 7P modules and why?
The finished battery is intended for a load of 7A constantly (which is 1A per cell ~ 0,4C) and 20A peak (2,8A~1C).
EDIT: I already have a BMS with ballacing fucntion, designed for 10A constant load and 20A peak load.
I would like to build a 10S7P battery pack for my e-bike. I harvested many cells from old notebook batteries. I picked identical Samsung ICR 18650-28A cells for the battery, I do not want to mix different brands and types.
I measured each cells capacity,charged themto 4,2Vand let sit forabout 8 weeks.Today Imeasured the voltage. The results are in the attached file asmAh;voltage.
My question is how to best match these cells to a 10S7P configuration.
Should Ibuild each 7P module with batteries that have capacities as close as possible and as a result have ten modules with bigger difference in overall capacity, or mix cells so that all modules have similar total capacities and each module will consist of mixed capacity cells? Matching voltage is more of a theoretical question, as the differences are very low, basically between 4,17V and 4,19V, with only two cells at 4,16V (as you might have noted, I posted the results for 73 cells, I need only 70 in my battery, so 3 cells are extra).
How would you match the cells for the 7P modules and why?
The finished battery is intended for a load of 7A constantly (which is 1A per cell ~ 0,4C) and 20A peak (2,8A~1C).
EDIT: I already have a BMS with ballacing fucntion, designed for 10A constant load and 20A peak load.