Battery going bad??

We just spent 3 days camping in a non-electric site (Fri - Sun) and the battery seems like it didn't do it's usual good job of holding a charge.
Started the weekend at 12.9 volts. Used the sink pump, interior lights (very little), and ran the fan all night, both nights. We usually do this.
The battery read 11.3 volts as we were packing things up Sunday afternoon.

When we got home, after a 3 hour drive, the battery read 11.8 volts. I've never paid attention to how much improvement we got after driving, so I don't know if the increase from 11.3 to 11.8 is good or bad.

Is there a way to 'load' the battery to test how well it is holding a charge? Does it sound like it's going bad, or is that kind of drop normal with that kind of use?

 

I will try to check them later today, Evan, thanks. Assuming they are not loose, is this type of discharge an indication of a battery gone bad?

 

Dave, I have not checked the terminals at this point. It seems to have taken a charge well since being plugged into a landline. We'll give it a good workout this weekend, though, and if it loses it's charge like it did, I'll investigate further.