I'm about to buy my first automatic chicken door. I chose run chicken because it's the only decent door available in EU (I wanted to bu ypullet shut but shipping+import taxes rise its price at impossible levels).
Since it's very hot in summer where I live and the side of my coop that is in direct sunlight can get up to 80°C on metal surfaces, I need to place the door on the inside or the batteries might explode.
I chose a model with no solar panel right for this reason (very dumb choice from run chicken to not give a separated solar panel).
If I program it to work on GPS, it shouldn't need the sunlight to open and close, right?