I have three 12V lead acid batteries. I want to charge them in parallel and discharge them in series. I designed a circuit using switches and SPDT switches. The simulation works, but I was hoping a more experienced EE could shed some light on possible real world circuit issues as I'm not really a power systems guy.
The circuit is extremely simple but I won't take any chances with power systems since the 36V system will be powering BLDC motors and circuits I saw on the web for charging in parallel and discharging in series are scarce. I'm a bit worried about parallel battery charge balancing though battery 2 will be the point where the charger will be connected to aid with that problem, so the approximate amperage per battery should be okay.
I plan to build the circuit using relays to replace all the switches and an MCU will be handling switching order.
The circuit works when SW4 and SW5 are in the closed position and SW1 and SW2 are in position B with a charger replacing R1; the batteries charge in parallel @12V.
When SW4 and SW5 are in the open position and SW1 and SW2 are in position A with a load replacing R1; the batteries discharge in series @36V.