Hmm, my Xantrex reads a low of 13.9 up to 14.7 while driving or idling. I also have a scan gauge II which reads direct battery voltage (chassis) battery. It is always the same or within .02 of the Xantrex.
I was having a slide issue a few months ago, partly contributed to low battery volts, even though I was plugged into shore power!
You might want to start by checking the water level in your chassis battery, if they are okay, next I would have the chassis battery checked to insure it's still good. On my last 5,000 mile service, Ford recommend my chassis battery be replaced, I've only had the coach a little over a year and a half, however, no idea how old the chassis battery is, it could have been sitting on the chassis for 6 months or in a warehouse somewhere!
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