I've read the Martian. It's kind of fun to think that electric vehicles could at least theoretically operate on Mars. (The batteries would have trouble at low temperatures and I definitely have the wrong tires. The motor is sealed, but not well enough for Mars, and sand would eventually get into and destroy a lot of the moving parts.)

It's also fun to modify machines to be used in ways they were never intended by the original designers. Fortunately a lot of the DIY electric car components are pretty flexible in terms of how you use them. For instance, you can get your motor controller, your battery management system, and your charger from different companies and reasonably expect them to work together because they each have a well-defined job and that's all they do.

I re-read Artemis now that I know something about welding, and was kind of disappointed it was all oxygen-acetylene, which I know next to nothing about rather than TIG, which is usually the recommended way to weld aluminum. (I'm not sure if you'd even need a shield gas like argon in a vacuum environment?) Maybe there is a good technical reason for that, but it wasn't explained in the book (nor does it really matter to the story except to the 3% of readers who care about welding trivia).

No, you wouldn't need a shield gas, and if I remember right Jazz is forced to borrow a tank of argon from her dad so as to not tip him off that she'd be welding outside, even though she wouldn't be using it.