Sump pump battery back-up

I have a sump pump that I think is 1/2 hp, but could be 3/4. I’m looking for a battery back-up. So far, I’m seeing back-up systems that come with primary and secondary pumps, the latter being a/c and the former drawing from battery. Some recharge the battery automatically, but others the owner must do. Lots of other variables. Does anyone have experience or recommendations? TIA.