Running a door UPS so it lasts

Door back-up units are commonly replaced early, and usually for one of three reasons that have nothing to do with the unit.

A door back-up unit is switched on once and then ignored for years, which is why they tend to be replaced earlier than they should be.

Three habits account for most of it. Leaving the unit switched off at the wall, so the battery sits discharged and sulphates — a battery kept flat is a battery being destroyed slowly. Undersizing, so every cycle runs the unit at its limit. And siting: a unit above a shutter head sits in the hottest, dustiest part of the opening, and heat is what shortens a battery.

The operating sequence is worth following rather than improvising. Mains on before the unit; unit on before the door is used; and on shutdown the reverse, so the motor is never switched by removing its supply. A monthly cycle on battery — close and open the door once with the mains off — tells you the unit still works, which is otherwise something you discover during the storm.