I got one of these, which is 12volt and is powered by the cigarette lighter
http://www.halfords.ie/webapp/…12473#tab1
A handy yoke, packs away very small in a bag. but only for light cleaning. I only paid €40 in currys for it.
Hopefully it will be handy when away for extended breaks, but dont use it at home to clean van, as the suction is not great!