Possible to use mutli-cell LiPo battery as if individual 1S cells?

The Rocketry Forum

Help Support The Rocketry Forum:

soopirV

Well-Known Member
Joined
Sep 1, 2010
Messages
1,157
Reaction score
6
Laying in bed unable to sleep last night, and a few ideas came to me...usually that means they're bad, so I'll start with the one I think has the most potential for being wrong (but am not sure!). Could I use the balance charging port of a 3S LiPo battery to get 3 1S feeds? The way the packs are wired is as if it's three 1S in one shrink wrap, so it is redundant...but, one source I found said that while possible, it's for low current applications:
https://www.tjinguytech.com/charging-how-tos/balance-connectors

That's from an RC standpoint, which I have no experience with, and while I know that firing an ignitor can be a high-current affair (an amp or so?), how does that compare to RC stuff?
 

woferry

Well-Known Member
Joined
Oct 9, 2013
Messages
805
Reaction score
27
Location
San Jose, CA
No, the balance connector still shorts 'adjacent' terminals together. I.e. the bottom cell's positive is shorted to the next cell's negative, and so on. You'd need separate access to every positive and negative terminal to change the battery from 1 Ns (series) configuration to a Np (parallel) configuration.

What that page is pointing out I think is that the balance connector gives you access to any one cell individually, for charging or discharging. I.e. if you had something that needed 1s voltage, you could power that off the balance connector while still having the 2-pin connector to power a Ns load. This is generally a bad idea though, if you put an extra load on one cell that the rest don't see you can throw the battery out of balance pretty easily, and the same goes for trying to charge cells individually. Balance charging generally puts the heavy currents into the top and bottom of the overall stack, and just measures and injects/extracts small currents from the balance taps to ensure the batteries remain balanced (it's why the 2-pin connector is generally heavier gauge wire than the balance wires).
 
Top