I have a 48V LiFePO4 system set up as a 0-24V system (Low) and 24-48V (high) system each with it's own MPPT. Due to limited space I am often unable to get the four solar panels for both to run simultaneously, and have therefore setup a 24V DPDT relay to switch the solar Input from three panels between the low MPPT and high MPPT.
What I am considering doing is to power the DPDT relay from the MPPT_Hi Load -ve (24V) to the MPPT_Low Load -ve (0V) so both can override the other. The MPPT_Hi Battery -ve and MPPT_Low Battery +ve come from the same terminal at the 48V system midpoint.
