Sure at your local Office Depot, Office Max. Look for APC Power backup. Or Amazon , Ebay, facebook , letgo. Look for them ( used ) $25-50.00 KIRK'OUT'PEACE
I use current pumps, i hooked up 1 of my 3 wavemakers (the one that is not programmable) to a APC 1500v. If power goes out, it will run that one pump for 4.5 hours. Ive never had a power outage last more than an hour so hopefully that will suffice....
Watch some BRS video on this subject.. Good suggestions there. I went with tunze set up. Either a 6040 6055 and 6095, 35 Amph battery either Harbor Freight or Batteries Plus, Tunze safety connector 6105.50.