Battery chemistry

Nick H

Finding my (electric) wheels
Feb 25, 2012
16
0
Hello All
I am looking to replace batteries and note BMS advertise 36v 15ah Li-Ion Nicomn and 36v 10ah LifePo4; they also mention 10 or 12s. What do the s digits represent & why different technology in 15 & 10ah?
Any advice would be appreciated.
Regards
Nick
 

patpatbut

Esteemed Pedelecer
Apr 25, 2012
859
79
S means series so 10S means 10 cells in series. P means Parallel so 3P means 3 Parallel.

More ah mean higher capacity so 15Ah is higher than 10ah.(more range)

Pat
 

flecc

Member
Oct 25, 2006
52,864
30,414
The LiFePO4 (lithium iron phosphate) have heavier cells and are a little bulkier than the Li-ion mentioned. They are also slightly lower voltage so more cells are needed in series for the given voltage.

So this means LiFePO4 with 12 cells in series are roughly equivalent to the Li-ion 10 cells in series. The nominal voltages per cell are 3.2 for LiFePO4 and 3.7 for Li-ion using other cathode chemistries.

The LiFePO4 have generally longer lives and take more charges than the Li-ion, which offsets the slight weight and bulk disadvantages.