Glider Independent Palm Nav Setup

Hi All,
I am looking for some advice on a palm nav setup,
my situation is this:
I don't own a glider, I fly club gliders, so I can't
rely on a glider having a particular wiring setup,
I already have a modern Garmin GPS, and am looking
to create a glider independent setup to switch between
gliders as needed. I've been looking at old r.a.s
threads and have sort of come to the conclusion that
an iPaq 36/3800 is what most people like, has anyone
tried running these off batteries other than the glider?
Does anyone else have any experience with this sort
of setup? Budget is quite limited (so £2000+ pieces
of equip are out of the question ;-) )

Any help greatly appreciated.

Cheers

Jamie Denton

p.s. to contact me directly, use the form on www.deviantpenguin.co
uk as the email address above is completely fake