Brian & Stefan
Take a look at this powertank aka jumpstarter
http://catalogues.repco.com.au/offer...urce=catalogue
It is currently on special until the end of April at Repco
I haven't physically seen it for myself but it will give 12V with the same 600Amp and I "think" it has the all important cigarette socket on the side of the unit which would appear to solve the shortfall of the one you saw at supercheap for $30 but didn't appear to have the cigarette socket. It also has a little light to boot on the front!
It probably wouldn't be enough to run multiple devices but for something that is small, easily portable and will run a mount for a few hours maybe it might be okay????
Brian - let us know what you think