I have 400 watts of solar cell on a motorhome charging a 200 AH Lithium battery. I like to also use the solar cells to keep my 'Starter' battery charged (it is a standard lead/acid battery). As both batteries need different charge settings, I'm asking if I can connect the solar cells output in parallel to 2 mppt? one set for lithium connected to the lithium battery and the other set for lead/acid connected to the starter battery. thanks
It is not possible to connect two MPPTs to the same PV array.
You could get another small panel and connect it to its own small MPPT or even a little PWM controller to keep your starter battery charged (that's what I did), or use a little auxiliary battery maintainer like a Sterling BM12123 or even a little Victron Orion-TR 12/12-9 converter to keep the start battery trickle charged off the house bank, or something similar... but no connection of two controllers to one array.
Thanks Justin for the suggestions - I like the idea of keeping the starter battery charged of the house battery as I would not need to install a solar cell and run a cable through the roof, but I'm wondering if it will be possible as currently the house battery gets charged 3 ways:
1) 400w solar with a MPPT Smart Solar Charge Controller100/30
2) from the alternator while driving with an Orion-Tr Smart 12/12 - 30 Non-isolated
3) 30A Blue Smart Single Output Charger when connected to mains
When I need the starter battery to be charged is when the motorhome is not in use for an extend time. So while parked in my driveway the house battery is always fully charged (I don't know where the solar panel energy goes when the battery is full??)
As you can see there is already a dc-dc charger connected, so if I connect another dc-dc going the other way (to the starter battery) will they not interfere with each other?
