RE: What is your favorite strange tool that you can’t buy at a regular supply house?
This is my favorite homemade tool. Rheostat to aid in cold weather charging. Once wired in series with the condenser fan motor, it allows the motor to become variable speed. I can dial in 90° day and charge the system to perfection every time. While charging, you do have to continually adjust the head pressure with the rheostat but, it works like a champ!!