Replace 3xAAA with one 18650?

I installed a solar powered flood light in my wife’s shed but it doesn’t stay charged long at all. I opened it up and inside there are three AAA batteries that appear to be knockoff eneloop style batteries. Each of these are 1.2v, so 3.6v total. Would it be possible for me to disable the solar panel and connect this light to one 18650 battery (or multiple 18650’s in parallel)? I think I would need to use a protected 18650 since there wouldn’t be any built in discharge protection. I don’t care about keeping the solar charging because it hardly works anyways.

I’d go with a built in 18650.

No need to disable the solar panel. It’s so low current it’ll never overcharge an 18650.

TLDR: Get a protected 18650, just in case.