I am installing a Smart Solar MPPT 75/15 on my boat, and will wire it to an AGM battery (Deka 8A4D). My engine starting battery (lead acid Deka 904D). The AGM will power the house loads and the starter battery starts the engine - they have separate positive cable runs. However, when my engine is on or when I am connected to shore power, I combine the positive cable runs so both batteries will charge from the engine or shore. This also means that the Smart Solar charger will now be charging both batteries. Are there settings on the MPPT that will work for this scenario? What are the drawbacks? Or should I not do this at all? (I suppose one work around would be turning off the charge controller when the engine is on, but that's not ideal.)
