Using a Car Adaptor with the M17x-R1?

So my family's gonna go on an 8-hour road trip in about a week, and I'd like to know if anyone has any advice in regards to powering my laptop for the long drive there. I've got an M17x-R1 with a Core 2 Duo P8600 and a single GTX260m.

The cigarette lighter plug in my family's Prius says "120V" on it, so I'm guessing that's the limit to how much power it can output. The power brick for the M17x says that the "input" is 100-240V of power. I have a DC-to-AC power inverter that says it can do 140 watts of continuous power and 280 watts of peak power.

I've never powered my M17x through a car's cigarette lighter before (done it plenty of times with the M1710 and the M1730) and I have no idea what to expect. Are there any risks of me causing damage to the car if the power draw becomes too much, or are there any ways to control how much power my M17x uses? All I know is that shutting off the dedicated GPU will reduce power draw, but is it still safe?

Any help would be greatly appreciated!

 

I don't think it will work I tried this on my R2 and when I plugged my charger in to the inverter the blue light would come on, but when I plugged it in to my laptop it would turn off. If you wanna see for yourself take your laptop and charger to the car and try it might work for you with the 9400m.

 

I had a weird issue trying to run my Gateway 7811FX with my power inverter. It has somewhat similar specs to your R1...

What happened is it would run fine while the car was moving and revving. The emergency alarm on the inverter would buzz if I was idling.

What I advise you is to try it out, see if it runs fine without any alarms or fuses blowing. If all works well for the first 10 minutes, it will likely work fine the entire 8 hours. Just keep in mind you are drawing power from the battery, and if the car has a bad battery or bad alternator, you could drain the battery and strand your family. In other words DEFINITELY don't use the laptop while the car is not in motion.

Edit: Considering that it's a Prius...Dunno if I'd risk using the laptop too much - the electric-heavy power system of that car might be sensitive to large power draws like that. I would ask in a Prius forum if I were you.