Switching batteries to start the motor.
Both batteries on my simple boat perform the same function (starting and bank), though I will switch from one or the other when on the hook overnight (for example) to ensure one will start the motor in the morning, while the other runs lights, etc..
I assume this simply assures that I have a full charge on at least one battery to start the motor, though usually the one I have used overnight will still start the motor. Should I switch back to both batteries to start in the morning or switch back to the fully charged battery?
By switching to both, I assume I bring the charged battery to the same voltage as the partially discharged battery (splitting the difference).
Does it make a difference to either battery or the starter, or is potential - potential, any way you get it?