Add a battery backup to your garage door opener

Last Updated on 8 months by Christopher G Mendla

In many cases, a power failure will preclude opening a garage door with an automatic opener. 

The Problem – A power outage may mean that you can’t open your garage door.

If the power goes out you may find that you can’t open your garage door from the outside or inside. In some cases, especially with elderly or disabled drivers and passengers, they depend on the garage door to enter and exit their home.

Can’t open the door from the outside

If the power goes out and you don’t have an automatic backup generator, you may find that you can’t open the garage door.

Some people add a manual disconnect that will allow you to disconnect the door from the opener from the outside and manually raise it. These disconnects are not very common. In addition, some people may physically be unable to open the door.

Can’t open the door from the inside.

Almost all garage door openers have a disconnect system inside the garage. You pull on the handle and a rope disconnects the door from the opener allowing you to manually open the door. At least that is the way it is supposed to work. If you have a car in the garage just getting to the disconnect handle can be a problem. In some cases, the mechanism might not disconnect. In other cases, there might not be enough room between the vehicle and the door to easily open it.

As mentioned above regarding access from outside, some people can’t physically handle manually lifting a garage door.

One Solution – Add a battery backup.

You can add a battery backup that will allow you to open and close the door at least 2 to 4 times. The same UPS (uninterruptable power supply) units that are used for computers can be used to power a garage door. A UPS contains a battery that is constantly charging. When the power goes out, the battery provides power to the outlets of the UPS.

If you have the slightest doubt about wiring, loads, codes or other issues, you should consult a licensed electrician.

Sizing.

UPS units are rated in terms of Volt-Amps. You need to select a unit that has a rating that exceeds the electrical load of your garage door. An undersized UPS will either not work or will sound an overload alarm when the door is in operation.

There should be a plate on your garage door opener specifying the wattage of the unit. It could also be specified as amps.

Note that most openers also have a light bulb. If the opener specifies 5 amps and has one 100 watt light bulb, then the draw is 5.9 amps since a 100 watt bulb needs .9 amps.

This isn’t an exact science. so you want to over specify your UPS.

In this case, let’s say we have a 5 amp opener and a 100 watt bulb, that is 5.9 amps. Since UPSs are rated by volt-amps, we need to go to a calculator such as https://www.rapidtables.com/calc/electric/amps-to-va-calculator.html . Most home wiring will be single phase. We’ll enter the amps and volts and press calculate

This tells us that we need a UPS with a rating of at least 649 Volt-Amps. That does not mean that you should purchase a UPS with a 650 VA rating. You want a margin for error.

Note that older openers may draw more than an new opener with a similar amp rating.

In this case, a 1000 VA UPS should be sufficient. You can purchase UPS battery backups online.

Installation

You need to place the UPS so that the Garage Door plugs into the BATTERY outlets of the UPS. You should minimize any extension cords. Be sure to use a heavy enough cord for the load. Again, if you have any doubts, consult an electrician.

You also need to make sure that the unit is secure, ideally on a wall and not hanging from the ceiling. Having a 20 pound unit dropping from the ceiling could cause serious injury to people or to your shiny new vehicle.

Make sure that everything required for the open is plugged into the outlets marked ‘battery’ and that nothing else is plugged into the UPS. Be sure that family members and employees know to not plug anything else into the UPS.

House wiring outlet capacity.

Keep in mind that when the power comes back on, there will be an additional load on the house wiring and that particular circuit to charge the UPS. You should verify that the outlets you are using can handle the load of a charging UPS while the door is being operated.

Electrical codes

Keep in mind that there might be local electrical codes that could apply.

Mark the date and set a reminder

The batteries used in UPS units have about a three year lifespan. After that, they should be replaced. Mark the units with the date of installation. Make a note to replace the batteries.

Test the system.

Give the UPS a day to fully charge. Then, simply unplug the UPS from the wall. Test the opener from both inside and outside. Keep in mind that the battery will start depleting when you use the UPS in the battery mode.

The higher end units will have a display showing the load and battery status. The run time will not be that relevant as it is meant more for applications such as computers.

If you have devices such as a keypad for entry, make sure those work.

In the example below, the load on the UPS while the door is being raised is 75%. This is well within the range of the unit. The battery is at about a 50 percent charge. If you do need to use the UPS in a power failure, keep an eye on the battery status.

Note that many portable generators will not be able to reliably charge a UPS. So use the UPS sparingly. This has to do with the sine wave that a generator creates and if that wave is compatible with the UPS. In some cases, you can power the UPS off while charging and power it back on when done. In some cases, a unit might be charged by shutting it down and plugging it into a generator.

Summary

Installing a battery backup for your automatic garage door opener can make life a lot easier during a short or long term power outage. The reserve power is limited so use it sparingly.

The effort will be rewarded when the power goes out and you need to get your vehicle out of the garage or when you come home in a howling storm and the power is out.