I’ve got a Sureflap cat flap operated by 4 AA batteries. It doesn’t work well on rechargeables, it seems to need 1.5v batteries.

I’m thinking to hardwire it with battery backup (like a Ups). I’m not very experienced in electronics, are there any off the shelf products I could use? I’m assuming the flap runs at 6v and that I can just attach two cables, one to plus, one to min.

If there are no off the shelve products, any recommendations for what I should buy?