Battery backup or UPS?

[Coasting]

we have a battery backup from crappytire that can also charge your car, picked up a decent generator after that last outage where people were out for days, and some battery airpumps.
But I have my family looking out for UPS backups on boxing day. It will be my luck that the power will go out the moment everyone leaves for work so there wont be anyone home to plug stuff into the our battery.
I want something to plug my powerhead or return pump into that will keep it going on its own until somebody gets home. My sump wont overflow either, and I have no idea what wattage my return pump is, but my main powerhead is only like 4w....