Thor Forums

[DenverTransplant]

Motorhomes always can supply surprises.

When I upgraded my batteries on my ACE 30.1, I also installed a battery disconnect switch to provide positive power shut off... or so I thought.

I installed the switch on the battery negative, just like I did on my old travel trailer. The switch on a wall in the battery compartment, so the original negative battery cable was rerouted to the switch and I installed a short battery cable jumper.

This week I turned the disconnect switch off before putting the Use/Store switch in the Store position. But when went put it in Store, I realized there were some lights still on. Funny... these should have gone off when I turned off the battery disconnect. What wiring error did Thor make?

Then after I bit of thought - probably no wiring error. I presume that the coach 12V negative gets tied to the frame, and the negative cable for the battery is also connected to the frame (haven't tried to trace this yet). The chassis battery is also tied to the frame, and its positive can be paralleled to the house 12V positive through the emergency switch. But the important thing is that the house and chassis batteries share the same ground.

So with the disconnect switch on the negative, all I'm doing is routing return current to the chassis battery. Not sure what the impact might be if current ran from the house positive to chassis negative for a long time, other than discharge the house battery. For me its been a non-issue as I always go to the Store position when I leave the motorhome (except for when I forget)

So it appears in this case if I want positive shut off of power, I need to put the disconnect switch in the +12V line and not the negative return. Having the chassis battery sharing a ground with the coach batteries results in a negative disconnect not working.

Has anyone run into this "feature"? Or did Thor actually make a wiring error?