Dash Voltmeter issue

[dukenrock]

My dash voltmeter will read normal (13+v) after the coach has been plugged in and then I take it on the road. After about 1-2 hours, the dash voltage will drop below 12V and work it's way down towards 10V. I plugged a digital voltmeter into the cig lighter and it reads 13.6V-13.8V while the dash voltmeter reads less than 12V. Today I took a 90 mile ride with the generator running and the dash voltmeter was right at the 13.8-14V mark. I think what may be happening is that the house batteries run low and then the dash voltmeter triggers to the house voltage reading. Is that possible, and if so, is it normal for my house batteries to drain so quickly while driving down the road?

[ga traveler]

Your house batteries should be charging while driving. There is an isolator relay that cuts in when you crank your engine and drops out when you stop the engine. These relays are bad about arching and causing the points not to close. Find this relay and first make sure it is getting a 12v feed when the engine is running. If it is getting 12v, then read the voltage on both sides of the relay. If they don't match, your relay is bad.

[dukenrock]

Thanks GA. That sounds like it could be the problem!