Truck Camper Solenoid Question

wwest wrote:
Using the tow vehicle's alternator/VR system to recharge a low SOC battery often results in boiling off the battery electrolyte, the better the electrical connection, the more likely the electrolyte will boil.

The alternator charging characteristics are such as to prevent overcharging (and "boiling") of the starter batteries on a long drive, so it is unlikely to do it to house batteries which are essentially connected in parallel to the engine starter batteries (which often consists of two batteries connected directly in parallel anyway.

What can happen if the alternator is relatively small, and the house batteries are very large and discharged, is the alternator will exceed its long-term rated output (which is usually way under the nominal rating) and eventually fail prematurely.

I prefer no to use the chassis as the return conductor for large current circuits because under some circumstances it can cause corrosion of dissimilar metal components if it flows elsewhere than through the steel chassis.