my cousin built me an electric powered reel for christmas a few years ago. It uses an old starter motor. A few other club members have built similar rigs but with small briggs & stratton engines.

Here's a video of the first trials: https://www.youtube.com/watch?v=8VHwhx93foU&t=8s

Since then we've realized that it needs to be connected to the cars battery, with the car running, to pull in all the rope. We've also double backed the rope so that its only pulling about 1000 ft at a time. Overheating of the starter motor is still a concern. https://www.youtube.com/watch?v=fKUZZ5Wt9kw

Happy to answer any questions and give any advice on auto tow. We are just getting into auto tow season here in Kansas. Lots of fun.