Finally some good news! I found another feedback algorithm that seems to work a whole lot better. I'm about to go out on a drive and see how it does.

I also added a staged output function to the current hardware. Basically, at the target temp, the fan goes to 50%. A few degrees over it goes to 75%, and at several above that, it goes to 90%. A few degrees below the target temp it stays at 25%, and if it gets too low it turns off again.

If the feedback hunts too much for their satisfaction, they can change one of the switches to enable the staged output.

So, I don't think there's anything in the way now of starting to build more and offering them for sale

This next week I'll get everything lined up so I can start cranking them out