Laptop with Inverter

Can someone explain how and where to measure the voltages to make sure plugging my laptop into a car inverter won't fry anything? My laptop is a Dell XPS 17, so the battery life is crummy, and the battery seems to be going bad. When logging the battery lasts maybe 30-40 minutes. The laptop's power supply is 150W, and I have a 400W inverter here I'd like to use. I plan on wiring the inverter power straight to the battery and the ground straight to frame.

An orange piece of paper came with the flashscan unit warning me about using an inverter and how to check if it is safe, but it was unclear as to where I'm supposed to measure the voltages exactly.

It's a V1 if that makes a difference.

Thanks!

Short answer is there is just no guarantee you aren't going to blow something up using an inverter, I would never use one, ever!