Just a thought...I have a local farm supply store that often will have lawn mower batteries on sale for $19.95 in the spring. I bought an extra one and am keeping it on a maintainer (floater). I don't know how many hours I'll get out of it but I'd think it would run a scanner at 600 MAH for a few days, I think it's a 350 CCA or something in that range. Haven't had enough power outages this summer to give it a workout, I'll probably put the scanner on it this winter and see how long it runs. And with the maintainer on it, it should last 4-5 years before it gets bad.