X2 on all the comments about checking your battery fluids level on a scheduled basis. I also include placing my hand on the sides of the batteries to make sure they are not getting hot.
I lost one of my GP24 batteries before learning this simple thing to do. My older ELIXIR converter put out a constant 13.6VDC and this is right at the boiling out point for battery fluids.
Since then I have installed a good four stage converter and this is on 24/7 here in my back yard setup running from my garage 15A/20A 120VAC setup.
Even though I have a good converter now I still out of habit check my battery fluids on a regular basis.
Been running my same three remaining gp24 Interstate 85AH batteries with good results for around five years. My battery performance is just now falling off - time to start thinking about replacement batteries. My plans are to get four each 150AH Trojan 12VDC T1275s but if money is still tight I will at least go for two groups of 2EA 6V 225AH batteries giving me just a tad less AHs I would get from the four each T1275s
Anything over my current 255AHs setup would work great for me...
Roy Ken