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No Domestic 12V Upon Engine Shutdown

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11-26-2024, 09:11 AM
Harold,Cat&Sam
No Domestic 12V Upon Engine Shutdown
I have a 200 amp manual reset circuit breaker for our inverter . In the background you can see our house battery disconnect switch .




Harold
Cat
Sam Miniature Schnauzer
3.8.2009 - 9.24.2021

93 30ft Breakaway
9209-3823-30BS-11B

KE5WCW
05-29-2026, 08:20 PM
Pirate19
The culprit was the thermal breaker which on my Breakaway is located on the forward wall of the domestic batteries compartment. As directed, I measured the voltage of each post. 12V in, 3.2V out. The symptom was resolved by bypassing the breaker.

Couple questions, please:
I notice a set screw (with a lock nut) in the middle. Can these be adjusted?
Is the same item available new? I did not find one.
If I bought a different breaker what should the amperage be?

It took a long time to diagnose this because it would occur rarely and then reset before I could test everything. Thanks Harold for your direction.




'92 Breakaway
Cummins 190hp, No Modifications
Allison AT542
Floor Plan 30-BS-11B
9205-3798-30BS11B
05-30-2026, 09:50 AM
Harold,Cat&Sam
Glad to hear you found it . Intermittent electrical problems are difficult to find .

You can replace it with one that has a reset like the one attached to my batteries. The one in my picture powers my inverter , so it is sized according to the maximum load of the inverter . You will need to have some idea of the actual amp load . Unless you are running an inverter on the same breaker , then your load will be the interior lights , water pump , stereo ....things like that are lower amp draw but do add up .


Harold
Cat
Sam Miniature Schnauzer
3.8.2009 - 9.24.2021

93 30ft Breakaway
9209-3823-30BS-11B

KE5WCW
05-30-2026, 11:07 AM
Pirate19
I have no extraordinary domestic 12V draw with the exception being I run a portable 750 watt inverter for my original old-school 19" TV. The inverter is pretty much at capacity. So that's 62 amps alone. My lighting is LED. Have a 3-way fridge.

So can you recommend an amperage for my replacement breaker?


'92 Breakaway
Cummins 190hp, No Modifications
Allison AT542
Floor Plan 30-BS-11B
9205-3798-30BS11B
05-30-2026, 03:30 PM
Dana
quote:
Originally posted by Pirate19:
I have no extraordinary domestic 12V draw with the exception being I run a portable 750 watt inverter for my original old-school 19" TV. The inverter is pretty much at capacity. So that's 62 amps alone. My lighting is LED. Have a 3-way fridge.

So can you recommend an amperage for my replacement breaker?


On mine those were labeled 80 amps. I had a number of them. I was able to reuse most of them. If memory is correct I replaced one with 80 amp like Harold.


Dana & Lynn
1997 38ft Monarch front entry
Spartan Mountain Master Chassis
Cummins 8.3 325hp
Allison MD-3060 6 speed
22.5 11R
Cummins Factory Exhaust Brake
8000 watt Quiet Diesel Generator
9608-M0022-38MI-4C
Christened Midnight

1972 22ft
72081169MC22C
Christened Camp Barth
05-30-2026, 04:21 PM
Pirate19
It appeared that I had a choice between 80 and 100 amp. You’ve made my choice easy. Would rather have the protection with the possibility of having to reset
Thanks.


'92 Breakaway
Cummins 190hp, No Modifications
Allison AT542
Floor Plan 30-BS-11B
9205-3798-30BS11B
05-30-2026, 06:30 PM
Harold,Cat&Sam
They aren't very expensive , so if you start with an 80 and it trips too often you can try a 100 amp . Most likely the 80 will be fine .

Our 2000 watt inverter is on its own breaker and cables , there isn't much load on our original 12 volt house system . Mostly just lights , water pump , vent fans , stereo , ham radios and the cb radio .


Harold
Cat
Sam Miniature Schnauzer
3.8.2009 - 9.24.2021

93 30ft Breakaway
9209-3823-30BS-11B

KE5WCW