Before I built a pond, I was in a fishing club that frequently required members to bring their own batteries. Lugging that lead-acid monster around wasn't fun in the least, and I even got tendonitis twisting my shoulder to lift it out of the boat!
I then bought a MUCH lighter (though expensive) lithium-ion battery. It seemed to work pretty well, but needed it's own special charger. Also came with warnings about very bad things that might happen if not handled & charged correctly.
From what I read, the lithium-iron-phosphate battery might be the way to go now. Safer and longer lasting, though not quite as light as the lithium-ion. Still much less heavy than lead-acid. of course. Here's one source of info on LiFePO4 batteries:
https://www.super-b.com/en/products
