This Batteriser thing is getting lot of attention. Although many scepticisme too. here is one of them;

http://theness.com/neurologicablog/index.php/batteriser-cool-tech-or-scam/

Electronics made to use rechargeable AAs have to work down to 1.1V so their claim of batteries being thrown out at 1.35V-1.4V isn't the norm.

Also it would prevent any low battery indication from working. Which is pretty vital in something like a smoke alarm. It'll just stop working without alerting.

For low draw LED lights, the ones with larger cases, I have successfully connected half a dozen mostly-dead AA cells in series (end to end) with aluminum foil and electrical tape. I just add as many as I need to get the needed output voltage. The key is to match their voltages fairly closely -- otherwise the weakest one will overheat and leak. (That's why a multimeter, even a cheap one, is IMO critical in any luggable kit for car, bug-in, or bug-out. Fix and improvise!)

Not sure how well it would work, but here's an interesting piece about using a solar garden light circuit to burn down half-dead alkalines:
http://www.motherearthnews.com/diy/get-p...r-zbcz1506.aspx

I look at it this way..... If 'it' has hit the fan then why not try it, if indeed it only costs about 3 bucks and there isn't any other way. I wouldn't use it in anything I'm fond of as a regular power supply but if it is all I had, then why not as a last ditch?