I have two identical solar panels in series that are connected to an MPPT controller (EPEver Tracer 1210A), which is currently charging two SLA batteries connected in parallel meant to power some lights. The overall solar panels wattage is 200Wp, whereas the MPPT is meant to support 130W at 12V.
I bought LiFePo4 batteries as I plan to power some tools so I need larger battery capacity. This however leaves me with two perfectly fine SLA batteries that I'd much rather re-use somehow. I know I can't connect the two different battery chemistries directly in parallel, so I'm trying to work out different solutions.
I have a spare PWM charge controller (your typical random chinese brand), so I was wondering whether I can connect the series of solar panels to both the MPPT and PWM controller (assuming the latter can tolerate the voltage of two panels in series) without causing strange behaviours (on the MPPT controller in particular, given the power tracking features) or other problems on either controller. The MPPT controller would be used to charge the LiFePo4 batteries, whereas the PWM controller would charge the SLA batteries. You can assume that both chargers have embedded reverse-charging protection, so the batteries won't be drained at night.
Is this a sensible setup?
Here follows a diagram. Apologies if it's not perfect: I'm not used to drawing electric diagrams.