I read the PDF and this thing is meant to run off your 12VDC car system (that means you can use any 12VDC source (probably 11-14 is acceptable). I've done some simlar type things and just used a little Gell Cell (sealed battery that I would rechange once in a while). I had an old 7Amp Hour unit that would run things for ever, but anything from 2Amp hour and up should last a couple hours or more depending on size. I put an inline fuse of about 1amp, just incase, and used the plug in connector that came with the adaptor I had for the way to turn it on and off (You might put in a switch?). On the other hand you could just put Eight 1.5VDC batteries in series to get your 12VDC, but I don't think it's as nice of a package (Just my oppinion).

Based on the PDF:
Pin 1 is your +12VDC (red wire)
Pin 3 is your common (Black wire)
Unit draws .8Amps or less

Good Luck, taking those high altitude pictures!