[ShrimpBurrito]

You don't say how long a period the batteries are not holding their charge -- a day? a week? That is important to know. Certainly if you go from full charge to 11 volts in a day and you don't know what the cause is (absent the fridge on DC or a short), then you probably have bad batteries.

Some of the known parasitic draws are the CO detector, stereo, gas water heater with electric ignition, and your solar controller. But all of those should not drain 2 Trojans in a few days.

I'd first turn off/disconnect the solar controller from the battery (and the AC cord to the camper, too, of course), get yourself a clamp-on DC ammeter, and put it around the positive wire right at the battery. Craftsman used to make one when they were owned by Sears for about $60, but I don't know if they still do. Be careful because many clamp-on multi-meters can't measure both AC and DC current, but only AC current via the clamp.

Ideally, you'll read 0 amps, but due to the aforementioned parasitic loads, there will be some current draw. What is that number? If it's only a few tenths of an amp, there's probably no weird current draws, and that would support the batteries being bad. If you have much more than that, then I would start pulling fuses one-by-one, assessing the current draw after you pull each fuse. That will narrow down the circuit that have current draws.

If you end up suspecting a bad battery, you can always use a battery hydrometer to measure the specific gravity of the acid in the battery. Trojan publishes reference charts for what you'd expect it to be.

Let us know what you find.

Dave