This is what annoys me most, everyone says humanoid robots would be perfect because they can work 24/7 without breaks. Well that's just a blatant lie, as you have stated already, current battery technology is utter crap for this use case.

Unless we can get batteries that can last 8+ hours, and fast charge, we aint gonna be seeing humanoid robots in stores/factories for a long time.

Unless you just attach a permanent power cable to the thing, which just would not work for many jobs.