I have a chinese one i bough like 10 years ago for 15$ maybe... I use it for football balls and inflatable pillow for camping... Once my tire was really down (Nail) so i inflated it fairly and went for repair...
For emergency, anything that blows air is good enough... i remember dad had a foot operated compressor :D

Umm, it's a four year old thread, and the poster you asked hasn't posted since January 2008 according to his profile. Maybe someone else knows, or maybe he is lurking, but it may have been better to start a new thread.

Cheers

Oh yeah I'm still around just don't own an X5 anymore :( So I don't follow up on this forum.

Got this message in my inbox at work.

The ARB compressor connects using crocodile clips, 1 to positive terminal in your engine bay and the other to any earth point. They have an on/off switch but automatically turn off when the small tank pressure get to 80psi. They also have a fuse. There it won’t cause any issue with electrics on the car.

Cheers, Wally.

I keep a portable air compressor in the X5. Comes in handy not just for the tires, but for when I bring my bikes along too and other stuff. I ordered a Viair and for the price and the reviews, you can't go wrong! ;)

Amazon.com: Viair 00073 70P Heavy Duty Portable Compressor: Automotive