A guy named Steven Harris put out a video series some years back on how to build a no-frills version. I made a couple that supply backup power for the diesel parking heaters running in a shed and garage. Wish I'd known about this product because I just replaced the batteries in my mine. Mine aren't really portable, and now that I'm sharing a home with a wheelchair user, running drop cords all over the house isn't an option.

3 Body problem was already on my list. My wife tells my son after watching the trailer: you know your dad is gonna want to watch this shit.