Adding battery back-up to after-market stereo?

Sorry if this has been posted before. I asked in my regular forum, no bites yet. Figured I'd give a try at the experts. :D I'm google'ing for it, but so far all I'm getting is hits for UPS' & other junk : http://www.google.com/search?q=%22battery+back-up%22+%2B%22car+stereo%22+-ups+-ipod+-alarm&hl=en&lr=&rls=GGLD,GGLD:2004-29,GGLD:en&start=40&sa=N

Anyone know what part I'd need to add to the power line of my aftermarket stereo (AIWA CDC-X504MP) to retain the settings when I pull the power when I do maintenaince? I know, I know, its not that big a deal, but its a hassle nonetheless.

I've seen mention of such a part in other forums, but the post I recall is not there anymore.

I can't for the life of me understand why we can send a probe to Mars but we can't get stereos with a NiCAD battery that'll keep my stereo settings.

Thanks.

Part? Sure, it's called a 12V battery. Just get a couple of those 6V pop can sized batteries from a hardware store or something, connect them in series and use a pair of alligator clips to connect them to your battery leads (before you disconnect them from the vehicle battery). I've never heard of a deck with an internal battery, probably because in most cases it takes all of 2 minutes to set things up like clock, stations, etc, unless you have an advanced EQ or something.

you could also try an AC powersupply from walmart or whatever, if you have household power nearby. I don't think there's much a current draw while the car's off. Just pull the fuse for the door/ceiling light and you should be good.