Trick-L-Start discussionLooks like it only charges the engine battery when the house batteries are being charged. Nice idea.
I have a pretty simple Motorhome - the built in Ford engine has a fuse and relay to provide charging to an "auxiliary battery", and this is used to charge the house batteries while driving. The relay connects the engine battery to the house battery when the engine alternator is charging. Trick-L-start in reverse. When parked at home I wanted to have the batteries connected so the solar panel could charge both house and engine batteries. I unplugged the relay in the fuse box and put a piece of wire in its place.
I never intended to use that connection in other situations but it was nice when camping and of course made no difference when driving so the batteries have been left connected for a couple of years now, except in winter when all the batteries are disconnected. The solar panel has kept the house batteries over 80% charged all the time so no worries about the house draining the engine battery when camping.
