If you're open to getting an outlet installed in the proper spot take a look at the direct drive options. They clamp directly to the torsion tube, and the motors can be replaced separately if they go out. As a bonus there's no overhead drivetrain so the sound is a fraction of even the belt drive models, and also nothing to clean or lubricate (other than the door itself). The models available are basically scaled down versions of the commercial units and were designed for durability from the get-go, overhead models are a comprise design to work with the older-style springs.