Coach Battery power off and on?

Yes, any of the above could be causing you to loose power from the house battery to the coach.

First thing is to check that connections at the batteries are clean and tight.

Visually check for other connections-- if you have your coach's wiring diagram follow the positive wire from battery to salesman switch. So, you likely have a large breaker/fuse and then either a mechanical salesman switch or a solenoid-based one. Again check connections.

If all that is good, and you have a solenoid-based salesman switch, next time this happens pull out your voltmeter:

One large lug will have 12 VDC from the battery-- confirm. If not, problem is between there and the battery.

With the salesman switch on, the other large lug should have the same voltage-- confirm. If not either the solenoid is bad or the it is not getting the "signal" from the salesman switch. Some solenoids have one small terminal, some two. If one, it will be the positive (should read 12+VDC) from the salesman switch and the body of the solenoid provides the ground. If two, the second will be ground.

SO, if the small positive terminal has 12+ VDC, but both large lugs do not have the same voltage as each other and the battery, the solenoid is bad. If no power to the small positive terminal, find out why.

We had that same thing happen. It was the relay that the "salesman" switch operates. Replaced relay and all is well.

Perhaps there is an automatic circuit breaker inline that trips and resets. Just a thought.

As stated you have a open, or a loose connection. Next time you loose power, If I understand , you have power if engine is running, If that is so then check you relays .

1. check battery voltage, working your way back to power junction.

2. Check your power connectors in the power block "where every it is located.

You might check you Couch power switch locate at the door on mine. I have a different RV but if I turn off the couch power and crank engine I then have 12 vote power back to system. Turn off engine and power is lost.

The coach has two deep cycle 6 volt batteries tied together. We have 12 volt power when driving down the road and when the gen is on. Just took the two batteries to local Interstate Battery and had them checked and they were ok.. Just replaced them in 2014. I checked the voltage coming off the converter and it was 13.6.

It is frustrating that we have coach battery power and then we don't when the motorhome is not running.

Escapade wrote:

Where do I look for the coach battery power short? Thanks for any help.

This is not a short but an OPEN.
It could even be a connection failing INSIDE the batteries.

How many batteries do you have and how are they connected ??

But are you saying that you have no 12V even when the converter is running sometimes.....as in, gen running or connected to shore power ?