Charging discharging multi-pack LIPO powered system

Thread Starter

ROVguy1

Joined Aug 10, 2017
2
Hello Everyone.

I'm working on a circuit/system that has 2 LIPOs is series. One is a 5 cell and one a 4 cell. I can't remove the batteries out of the system to charge them so I'd like to setup a circuit that allows me to do that safely in the system.

What I'm after is a way to switch the batteries between series circuit while in use and change them to parallel for charging. I'm thinking mosfets will do this but not exactly sure how to setup the circuit.
I have a drawing of what I mean below.
My space is also very limited so I can't use large relays.

Thanks
Battery switching circuit 2nd.PNG
 

Dodgydave

Joined Jun 22, 2012
11,285
Your circuit is ok, i would use a DPDT switch or relay if your switch is not of high current capacity, your only problem is the charging of the cells as they will be of different voltages, and so will need two separate VAA supplies.
 

Thread Starter

ROVguy1

Joined Aug 10, 2017
2
Your circuit is ok, i would use a DPDT switch or relay if your switch is not of high current capacity, your only problem is the charging of the cells as they will be of different voltages, and so will need two separate VAA supplies.
Thanks Dodgydave.
That difference in charging voltages would be an issue. I'll need to make them both 5 cell.
Would you say that this circuit below is the same setup only with relays? NH=Normally High, NL=Normally low.

Thanks.
Battery switching circuit with Relay.PNG
 
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