Is there a car adapter for the C3500 available from Averatec? I didn't see an obvious one on their site.

I just use an inverter I got on eBay for $5, it works.

Averatec does sell an auto kit. here is the link. Hope this helps.

http://www.averatec.com/accessories/adapters.htm

That's where I went originally, but the car adapter doesn't list the C3500 on it .. the AC adapter does however.

Let me be a little bit more specific about what I am refering to on that page:

Belkin Auto Adapter
The Belkin ACAnywhere Car Adapter is a compact and portable power solution for mobile users. The notebook auto adapter allows you to plug your notebook computer directly into a vehicle cigarette lighter to keep you powered on the go. This 140 watt car adapter works with all Averatec notebooks.