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S-L-M · 08-31-2022, 11:35 PM

2017 Class C
My coach batteries suddenly stopped providing power to my coach. My first suspect was the disconnect switch. But my batteries are at 12.8V because I keep plugged in to shore power. Doesn't that indicate that the switch is on and functioning properly? The switch has to be connected to charge, correct?
All circuit breakers are on.
What's my next troubleshooting step?
Thanks
Steve

KtownKajun · 09-01-2022, 04:01 AM

Dave,
Check all battery grounds, after that I would start with the push button battery disconnect switch. In our coach the push button battery disconnect switch (Away switch)is by the door and it activates a solenoid which switches the battery system on and off. We also have a rotary disconnect switch at the rear by the batteries. This may or may not apply to your situation. The Next thing I would check is the solenoid that this switch activates- The solenoid sometimes fails and if it does, the switch won’t work as intended. Your batteries should charge either way if the coach is plugged in via some type of battery management system (bird system)

twinboat · 09-01-2022, 05:51 AM

12.7 volts is a resting, not charging battery voltage.

Plugged in, you should see 13.+ volts.

Look for a tripped breaker real close to the batteries then check the disconnect solenoid, controlled by the switch near the door.
Last thing is the reverse polarity fuses if you at any time sparked the battery cables. They will be in the fuse panel or on the converter/charger.

NevadaNick · 09-01-2022, 08:46 AM

The breaker close to the batteries that twinboat mentioned went bad on one of my trlrs

S-L-M · 09-01-2022, 08:54 AM

Will the batteries charge with the switch disconnected?
Should I hear the solenoid click when I turn on the switch?
How do you check the solenoid?
Batteries are a few years old, but even at 12.8V they should at least give some dim light shouldn't they?

IAlreadyGot1 · 09-01-2022, 09:27 AM

Quote:

Originally Posted by S-L-M

Will the batteries charge with the switch disconnected?
Should I hear the solenoid click when I turn on the switch?
How do you check the solenoid?
Batteries are a few years old, but even at 12.8V they should at least give some dim light shouldn't they?

The disconnect switch is on the output side of the battery. It disconnects loads from the battery. The charger is on the input side of the battery. The batteries will charge with the switch in either position. If the 12.8V measurement is taken at the battery, that reading does not verify that the disconnect switch is in the closed/on position, or that it is functioning properly. The switch is downstream from the point of measurement.

Your disconnect switch may be defective. It could be bypassed, if you are comfortable doing that sort of work. First, I’d check all 12V fuses and wiring connections, as others have mentioned. Second, as previously mentioned, the 12.8V reading indicates fully charged, resting batteries. It also indicates that he batteries are not being charged. Check your shore power connection and charger settings to determine why that condition exists.

S-L-M · 09-01-2022, 10:11 AM

Quote:

Originally Posted by NevadaNick

The breaker close to the batteries that twinboat mentioned went bad on one of my trlrs

I have not found this breaker. Where might it be?

twinboat · 09-01-2022, 11:02 AM

You need to follow the positive cable.

S-L-M · 09-01-2022, 05:30 PM

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Found breaker. I can't trip it, does that make it defective?

twinboat · 09-01-2022, 06:57 PM

Your picture didn't come out. Try again.

S-L-M · 09-01-2022, 08:01 PM

It was a bad question. I tested the breaker, it is good. Figured it would be easy to replace the batt disconnect switch but after pulling it apart it has no part number. Going down a rabbit hole

IAlreadyGot1 · 09-01-2022, 08:15 PM

Quote:

Originally Posted by S-L-M

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Found breaker. I can't trip it, does that make it defective?

Quote:

Originally Posted by S-L-M

It was a bad question. I tested the breaker, it is good. Figured it would be easy to replace the batt disconnect switch but after pulling it apart it has no part number. Going down a rabbit hole

Meter the voltage from disconnect switch posts to ground before you start throwing money at parts that might not need to be replaced.

donr103 · 09-01-2022, 09:04 PM

Any reason you don't stop by auto parts store and have batteries tested for free? If I was trying to just use process of elimination.. that is 1st thing I would do..
Good luck and keep us posted

THenne1713 · 09-02-2022, 12:31 AM

If you have not serviced/ removed battery lately, I suspect REVERSE POLARITY FUSES on POWER CENTER are good, but you have Tripped a 12vdc CIRCUIT BREAKER beside the battery (probably 30a-60a?)... should be within 18" of battery, maybe in adjacent compartment, or with vapor seal separation, if inside same battery box? When my hydraulic slides were tripping breaker, it would kill the POWER CENTER, TOO