like i said it bi direction, either side can charge either side
if the car is running, the alternator is charging, when the starter battery gets over 13v it connects the house battery, then the alternator charges the house battery
if the car is off, the solar/generator/shore power charges the house battery, when it gets to 13v to connects the starter battery and charges that battery
your making a big deal out of the relay for no reason, you should be in auto mode 99% of the time.
let it do its job and forget about it, there is a led on the relay itself that shows what mode it is in, if you care
leave it alone in my opinion it only benefits you.
this is no different then a isolator which is standard in rv's, with the added benefit this unit will charge the starter battery, isolator's don't
your alternator will be fine, if you still don't want it, i'll be more then happy to pay for shipping to my house for it :-)
