Originally Posted by OldCoot
Looks to be floating a little high.
That's funny right there..
Back to the OP: Generally dry camping it really would be in your best interest to invest in something like the trimetric. As was mentioned, you can really kill your batteries prematurely by not adhering to a pretty strict charge/discharge regime. I don't know what you have in the way of a battery bank, but for me, spending $150 for a decent meter is a small price to pay for $1200 worth of batteries.
When you're reading in the 13's its typically a residual ghost charge after a recent charging cycle, or as some mentioned about being plugged into shore you're also picking up the float charge still feeding the batteries.