Generator/Battery issue

[BlossomStein]

Hi Folks.

I have some folks with a 2018 28A with a 450 chassis. One chassis battery, one onboard Onan generator, and one group 31 deep cycle house battery.

Both batteries test good.

All fuses and breakers are good.

The generator charges the house battery at just under 14v.

They use the house battery until it dies, then (of course) they can't start the generator.

Running the engine does NOT charge the house battery or enable the generator to start.

I have not found a battery disconnect switch anywhere and the rental company (yes, a it's a rental and the folks are 800 miles from home... you have NO idea the shape this thing is in) midnight tech support girl said that the RV does not have a battery disconnect switch.

Anybody know of a switch on this model?
Anybody know if the engine is wired to charge the house battery?
Anybody have any other ideas?

Thanks.

[Bob Denman]

The engine alternator should charge the house battery...
But why not just hook some jumpers to it; and get the generator started up?

[BlossomStein]

I know it should, although I do know there are some coaches that, for whatever reason, do not. I'm convinced that this one should indeed be charging the house battery.

I'm a mobile tech and in addition to fixing the black tank that had literally fallen out of the bottom of the coach, breaking the pipe and splitting open the tank and doing several other things for these folks, I explained that the gen needs power to start up (they hadn't known that the fridge, heater, or hot water were supposed to work when the engine or generator weren't running because nobody had explained to them that there was a house battery or anything else... complete train wreck. It's odd that the engine will run the house lights but not charge the house battery. I'm just stumped.

I told them the jumper cable trick, but honestly I think they're scared to try it. They now want to pay me to buy a new battery, drive 60 mountain miles, and swap the house battery to hopefully get them back home over the next two days. That is the level of mechanical comfort we are dealing with here...

[16ACE27]

The problem with a rental is that it is not necessarily built like a standard RV, and add to the fact that not all Class Cs charge the house battery from the alternator and you really never know what you're dealing with.

I assume no "Emergency Start" button/switch either to tie the chassis and house batteries together? Although that may not even engage if the house batteries are too low.

[Beau388]

Originally Posted by BlossomStein

Hi Folks.

I have some folks with a 2018 28A with a 450 chassis. One chassis battery, one onboard Onan generator, and one group 31 deep cycle house battery.

Both batteries test good.

All fuses and breakers are good.

The generator charges the house battery at just under 14v.

They use the house battery until it dies, then (of course) they can't start the generator.

Running the engine does NOT charge the house battery or enable the generator to start.

I have not found a battery disconnect switch anywhere and the rental company (yes, a it's a rental and the folks are 800 miles from home... you have NO idea the shape this thing is in) midnight tech support girl said that the RV does not have a battery disconnect switch.

Anybody know of a switch on this model?
Anybody know if the engine is wired to charge the house battery?
Anybody have any other ideas?

Thanks.

I am not a Class C person but from previous post there should be a BIM (battery interconnect module) near the chassis battery. The BIM replaced the old Trombetta module and relay (BIRD) in the house battery compartment.

[Judge]

Many of the Thor Class C's do not charge the the house batteries when the engine is running. It may have an emergency start switch. If it does, you can temporarily tie the house battery to the chassis battery but you would need to continually hold the switch to allow the alternator to let is charge the house battery.

[BlossomStein]

Since I can't stand it when people don't tie up their threads...

After tracking down some wiring I discovered an isolator and it's control box hidden discreetly under a dangling coolant overflow tank on the opposite side of the engine bay from the chassis battery. It would manually engage with the boost button in the cab, but the control board wasn't doing its job. I jumped both hot terminals on the isolator solenoid and the house battery started charging just fine. It was 10 pm by then at Lake Tahoe (high end tourist community) and the folks are driving back to Denver. Told them to USE THE FRIGGIN GENERATOR IN THE EVENINGS instead of just killing the house battery. Warned them that they will continue to not charge while driving.

Thanks for all of the input.

[Matts11211]

Blossom, did this happen to be a nice family from Israel? I think I may have bought this coach… ha. I sure hope not but it has its fair share of similar issues.