What's eating my batteries? (Please help:()

I was told these are sealed lead acid batteries(which means they don't need water added right?)One came with the RV and I was told it was new and then bought an exact match to make a pair. They are Autocraft marine deep cycle 27dc2. I posted a picture below. If that was the case am I to assume they are shot? How can I tell or test them. A picture is below. My converter is 45 amp model and my solar controller is a MPPT, should they avoid boiling it off? Shouldn't it still have been charged anyways after being towed? Sorry I'm quite new to all of this,(and I always seem to learn the hard way, lol). I sure hope that's not the case since I just bought these like three months ago. Although I would be relieved to know what it is fix it, and then hopefully not do that again, lol. I did pick the cheapest batteries I could find just for that reason.

I'll give that a shot my multimeter does have a dc10A setting. I have Trailer Life's "Rv Repair and Maintenance Manual" and the electrical section had nothing like this I was quite disappointed in it a a reference. I suppose I need to get the electrical specific one also. We live on it fulltime time so we're always on it or do you mean like when we were gone hiking?

Thanks for the advice,

Tim Czarkowski
TotalTravelers.com

I do see some white power over the negative terminal on one of the batteries. I assume that's not a good sign :(