time2roll wrote:
Testing voltage is great.... however next shop have them measure the amps. Need to load the Honda battery with the lights or something. Should see 10+ amps flowing from the RV to the car. Even 1 amp into a charged battery will show full voltage. If the shop does not have a clamp-on ammeter they need to get one or find a new shop.
Then put in towing mode and see what load is actually on the car battery to power the brakes etc.
This is an excellent point I hadn't thought about.
What gauge of wire are you using for the charge line and the ground wire going between MH and the towed? Both would need to be at least 14 or 16 gauge, I'd think, to allow sufficient amperage to keep the battery charged. Also, what amperage is the fuse you have on the charge line?
Maybe this is a case where you are taking power (amps) away from the Honda's battery faster than charge line from MH can replace it.