ok i am looking at this:

12v Sealed lead acid, its 84 Whr,



http://www.atbatt.com/product/22257.asp?utm_source=frog&utm_medium=cpc&utm_content=textlink-sealed-lead-acid&utm_campaign=frog1&utm_term=PS-1270-F2&gclid=CPDao9_fprMCFYpFMgodaDsAjQ $23.00 bucks

so that means i can pull 84 watts and in a hour before its dead correct?

so that means if i pull 40 watts then this battery should give me almost 2 hours of use,

i know of situations where i have not had -5v with some computer power supplies and it still works anyways,

sometimes though the serial ports suffer...

i was thinking of getting a 5v and 12v voltage regulator, wiring right to the +5 +12 rails.

if i am thinking about this correctly i can just hook it up and leave it up because the voltage regulator will work in the opposite when its charging????

that way it will not over change when plugged, so all i would need is a supplemental ( battery on/off ) switch.