> the middle of the field when I need to do things like weld farm equipment

There is an entire genre of welding equipment designed for this scenario.

https://bakersgas.com/collections/miller-engine-driven-weldi...

Exactly why the power source being the truck I already own anyway is far more appealing, at least it would be if the aforementioned problems were solved. Special tools come with special costs that don't really make sense most of the time.