Originally Posted by Apolima
Do not have a battery switch to connect to the house battery system.
If, in the remote case, the starting battery will not start the engine, use jumper cables in this emergency situation.
If you have a battery switch between starting and house systems it is too easy to forget that you left it on.
Of course this is where a VSR comes into play. I won't go into the full details, there are plenty of places on the internet where you can look up information. Basically the VSR connects the two batteries when the voltage at both is high (12.8V or over), meaning that a single charging circuit can charge both banks. When the voltage at either battery drops below 12.8V, e.g. as the house batteries discharge or the engine battery fires up the starter motor, the VSR disconnects the battery circuits. They are excellent set-and-forget devices.