MrWizard wrote:
the advantage of a Relay over Diode based
is no voltage drop from the diodes
this means higher voltage faster better charging for chassis and house batteries
if you 'want' manual operation
use a battery disconnect switch
just put in-between the camper battery line and the alternator chassis line
open hood close switch ..drive
get to camp, open hood, open switch
total isolation
I pretty much thinking I'll just insert the disconnect switch - two reasons :: It (probably) won't fail, and I can carry a spare. And, if the truck battery ever goes dead (why it would, I don't know if it's isolated, it shouldn't), then I can either jump start, or close the switch, and it will combine the batteries enough to start.
But I'm more concerned with not draining the truck battery because we camp a lot with no electric onsite. When the last one failed, we ended up with a dead truck battery as it drained with the house battery.
But then again, it's nice to have a relay that will fast-charge the house battery even after the start battery charges. Maybe the best alternative would be to install the isolator, and then a bypass switch for when/if it fails. Gotta think about that one ...