Any issues with creating an "unbalanced" Li-Ion pack?

ESK8 Electronics
#1

Hi Everyone,

Haven’t seen this one come up on the forum, but something I’ve been thinking about. Is it possible to have a 10S 2.5P for instance?

So basically if I have 25 cells, but want 10s. Some of the cells would be 2 in parallel and other would be 3. I can’t think of any reason why this wouldn’t work. Balance charging through a bms should still be the same. Would the groups of 3 cells having more amp output screw anything up?

Just thinking this would be a decent option to get a little more range and use all the cells I have available.

#2

A better option would be to buy 5 more cells and make a 10s3p

1 Like
#3

the smaller groups would run empty faster. Without a bms this may damage the cells, with a bms you won’t utilize the full power of the pack and also shorten the smaller pack’s cycle life.

Just get 5 more cells for 10s3p

#4

Got it. So basically the main downside would be you could never use the capacity of the 3p cells as the BMS would cutoff when the 2p reaches cut-off. So essentially it is like having 2p and the extra cells are just dead weight.

#5

correct. hitting the low voltage cutoff for the bms is bad for cycle life as well

#6

That settles that. Thanks!