Smart Lock Battery Died? How to Get In and What to Do Next

Smart locks rarely die without warning. They beep, flash or send an alert to your phone, and then, if nobody acts, the keypad goes dark. The good news is that almost every lock is designed for that moment. The catch is that the backup only helps if you know where it is before you need it.

The warnings before the battery dies

• A beep or a flashing light when you enter a code or lock the door.
• A low-battery alert in the lock's app, if it has one.
• The motor sounding slower, or the bolt taking longer to move.
• Codes that sometimes need entering twice.
• A keypad that lights up dimmer than it used to.

When you see any of these, change the batteries that week. A lock that's warning you still has enough power to work, which makes it the easy time to do it.

Getting in when the keypad is dark

Look at the lock's manual, or the maker's website for your model. The backup is usually one of these:

• A key cylinder. Many keypad locks still have a keyhole, sometimes behind a small cover. The key that came with the lock opens it.
• Battery contacts on the outside. Some keypads have two small contacts, or a slot underneath, where a fresh battery held in place powers the keypad long enough to enter your code.
• A backup through the app, on some models, when your phone is close to the lock.

If there's no backup, or the backup key is inside the house, it's a lockout. Call us and tell us the kind of lock on the door.

Changing the batteries without losing your codes

On most locks the codes and settings are stored in memory and survive a battery change. Still, it's worth doing it the right way:

1. Open the inside cover while the door is open, so you can't be locked out while you work.
2. Replace every battery at once, never just one or two.
3. Use the type the manual asks for. Some locks are picky about rechargeable or lithium cells.
4. Put the cover back, then test your code and the app with the door open before you close it.
5. Write the date on a small piece of tape inside the cover, so you know when they were last changed.

If the lock does ask to be set up again afterward, the manual shows how. Keep a written note of the admin code somewhere safe inside the house.

A lock that eats batteries

If fresh batteries only last a fraction of what the manual says, something is making the motor work too hard. The usual cause is the bolt rubbing on the strike: the door has shifted, the bolt drags going in, and the motor strains every time it locks.

• Try locking with the door open. If the bolt moves easily then but struggles with the door shut, it's an alignment problem. Our guide to a door that won't lock covers what to check.
• Cold weather shortens battery life too, on doors that face the weather.
• Very frequent use, or auto-lock set to lock after every opening, adds up.

Sorting out the alignment protects the motor as well as the batteries.

Plan for the next time

• Keep the backup key with you, or with someone you trust nearby, not inside the house and not under the mat.
• Set a reminder to change the batteries once a year, or at the first warning.
• Know where your lock's backup is, and try it once, on a calm day, with the door open.
• Keep spare batteries of the right type in the house.
• If the lock has an app, turn on low-battery alerts and check who has access every few months.

Thinking about a smart lock?

A keypad or smart lock is one of the best ways to stop house lockouts, as long as it's fitted properly and has a backup you know how to use. We fit keypad and smart locks at homes and businesses, and set the bolt and the strike so the lock isn't straining from day one. See smart lock installation for more.

Before you buy one, check that it suits your door. Our guide on measuring a door for a new lock shows the four measurements that matter.