I’ve seen the lithium batteries, and my only concern would be can my existing converter charge them? I know it has different settings and does include an AGM setting, but I don’t recall seeing a lithium setting. It’s the original converter so it’s 14 years old and I don’t know if Lithium RV batteries were around that long ago.
And I do have the auto-water filler and it seems most every time I check them I’m adding a half gallon of water. Last time I was at my storage shed I added a half gallon and I had just filled them three months earlier and had them disconnected for that entire three months. So just sitting there not being charged or used they lost a half gallon between the four of them.