Garage door opener backup battery: what it does and how many cycles to expect

A garage door backup battery buys you a short window, not a working door for the length of a blackout. B&D says its battery backup will usually get between two and four full cycles, and it counts one lift and one lower as a single cycle.

Leaving home uses one cycle: open, drive out, close behind you. Coming home uses another. So two to four cycles works out to one or two trips out and back. That's our estimate, worked from B&D's figure.

Our view at Levee Garage Doors is simple. Treat the battery as your way out and your way back in. After that, it's the manual release cord, which is red on Merlin openers, so check yours. The cycle figure belongs to B&D's own unit, so check your opener's manual for its own number.

How many times will a garage door backup battery open the door?

On B&D's own page the answer is between two and four full cycles, with lift and lower counted as one. That is a handful of door movements, not a day's worth.

It is still worth having. B&D pitches its backup for floods, fires and scheduled or unplanned outages, and makes the point that being locked out of your own garage can be a safety issue. Picture needing the car during a storm with the power gone, or getting home after dark to a dead street.

Spend the cycles on purpose. Open the door, get the car out, and close it once. Don't cycle it to "see if it works" while the power is off.

What happens when the power drops?

You don't have to do anything to start it. B&D says you don't need to activate it or charge it: it activates when the power goes out and recharges when the power comes back.

While it's running, the door isn't a bare motor. According to a Merlin dealer's product page, Merlin's backup powers the opener and its safety features. An audible signal sounds while the door runs on battery, and LED lights show whether the battery is charging, in use or needs replacing.

If the cycles run out before the power returns, the manual release takes over. Once the power is back and you've used the release, the opener has to be reconnected. Merlin's steps differ by door: for roller doors pull the cord again, and for sectional or tilt openers use the green button next to the red string.

Does my opener have a battery backup?

Don't assume it does. Merlin says its openers do not use a battery, unless your motor has a backup battery system installed, and your user manual shows whether yours has one.

Not every opener can take one either:

• Merlin. The Battery Backup 24V suits select Merlin garage door openers manufactured from 2009 onwards. Merlin's page lists the SilentDrive Elite MR855MYQ and the Commander Platinum II, Extreme II, Elite and Elite II. Two similar-looking single roller door motors can differ here: Merlin says the MR655 and MR855 differ in power, battery backup support and warranty.
• B&D. Its Battery Backup is compatible with all B&D sectional door automatic openers, and B&D says it comes complimentary with any Smart Pro garage door opener purchase.

A beep can mislead you. If your opener beeps or flashes while the power is on, B&D says the most common reason is that it is due for scheduled maintenance. A Merlin backup, by contrast, signals while the door runs on battery. Find the make and model number first, then read the manual.

Backup battery or manual release?

You need both, because they do different jobs. A common mistake is treating a backup battery as normal power or as a stand-in for the manual release, when B&D's own figure is about two to four lift-and-lower cycles.

The battery gives you a few powered cycles with the safety features working. The manual release works when the battery is flat, or when there's no battery at all. Merlin's blackout advice still puts knowing the red release cord first, ahead of the backup battery.

The short version of Merlin's release steps: pull the red cord down once, then push the door up by hand. Merlin warns: “Do not try to pull the door using the manual release cord; it will snap under the load.” Take care if the door is open, because weak or broken springs can let it fall rapidly.

We've written the full walk-through already. See how to open your door safely in a blackout and how to find your manual release cord before you need it.

How do you look after a backup battery?

Mostly by watching it. The battery charges itself, so your job is to read its signals. On Merlin's backup the LEDs show charging, in use, or battery needs replacing. When it asks for a new battery, get one matched to your model from a dealer or technician rather than guessing.

Both makers put a one-year warranty on the unit: B&D's Battery Backup and Merlin's Battery Backup 24V.

Fold it into the opener's regular service. B&D recommends servicing the opener once in the first 12 months and every two years after that. Merlin generally recommends an annual service, and says warranty-required servicing varies by opener, so check the manual. A service visit is a sensible time to confirm the backup still takes over when the power is cut.

Where does a backup battery fit in a storm-season plan?

NSW Storm Season runs between September and April, although major storms can happen at any time. The SES says that in its last storm season it responded to more than 23,416 incidents. Its advice starts with the basics: make an emergency plan and keep an emergency kit.

The garage door is one line in that plan. Merlin's blackout checklist runs in three steps: know the red release cord, then the backup battery, then keep the driveway clear. That order makes sense to us. Plan for the cord, use the battery while it lasts, and keep the path out free of bins and branches.

Bigger systems bring the same problem. The Bureau says a Category 3 cyclone's winds can cause power failures, which we unpacked in what Category 3 means for your garage door. Wherever you are across the Maitland LGA, from the flats to the hills, a blackout is when you find out what your opener can do.

Check your opener before the next storm

Start with two questions: does your opener have a backup battery, and can it take one? The model number and the manual will tell you. Our Readiness Gauge walks you through reading your door in five checks.

If you're still unsure, or the opener is beeping and you don't know why, tell Levee Garage Doors the make, the model and what the door is doing through our enquiry page. We'll talk it through before the next storm does it for you.