Thank you, what would you improve?
Well, I wouldn't take every suggestion above, but I'd start with the hot-spots (*) identified above. Swap the fuse for something better, cover the exposed terminals, think about the structure of the shelf and maybe beef it up and/or put the batteries lower, load-test it for a few cycles and see if it works like you think it should, run off it for a weekend to test it 'real-world' and see if it meets your expectations. I'm still impressed, you've put a lot of work into it, and it's a solid beginners build. [There's a wealth of knowledge here, but Perfect Is The Enemy Of Good, so don't try to meet everyone's goals here, just yours.]
Is there any side-to-side sway of the shelving unit? Maybe it needs a board or two across one of the open sides?
(*) If you see what I did there