I've done some research in the groups on backup sump pumps, and between the water powered pump, the generator backup and battery powered backup I've decided on the battery powered backup.
One thing that I wasn't able to find in the hour I was googling around the groups is battery selection. If I get a system from Lowes, I still have to provide a battery, and they provide a manufacturer 12volt battery that is 75 AH for $113. For that price, I can get two 650 AH batteries and run them in parallel. There's a local tractor supply store that will sell me the cables for the parallel hookup (that place has cool stuff).
The battery they sell doesn't look like a car battery at all, even though its 12 volts and heavy as can be (about 20 lbs?)
My initial assumption is that it should work fine to use a Walmart car battery (marine deep cycle), but there have been other things that I have assumed to be so that aren't.
Any thoughts?