I'm planning to have three batteries (one is a bank of house batteries) on my narrowboat, with charging via shore power, engine alternators (x2), 600w solar panels and a MultiPlus 3000 inverter charger. The main charge will be for the bank of House batteries, but I will also be using AUX1 of the MultiPlus to trickle charge (4Amp) the Starter battery. My question: is it also possible to trickle charge the Bow Thruster battery via the same AUX1 of the MultiPlus via a 12v 140Amp Voltage Sensitive Relay on the positive charge cable between the Starter battery and Bow Thruster battery?