As an Amazon Associate I earn from qualifying purchases. Links to Amazon on this page are affiliate links.
What happens when a smart lock battery dies?
Updated
The lock stays in whatever position it was in. If it was locked, it stays locked, and the keypad, fingerprint reader and app stop working. You get in with the backup the maker built in: a physical key on most models, and on some, a USB-C port you can feed from a power bank. Know which one your lock has before the day it matters.
You get warnings first
Locks do not die without notice. Schlage says the Encode shows a flashing low battery icon after a code is entered. August's FAQ says you get an app notification, then an email. Wyze says the Lock Bolt's low battery light flashes red. Change batteries at the first warning.
Backup by lock
| Lock | If the batteries die |
|---|---|
| Schlage Encode | Use the key. Schlage says Encode locks have no 9V jumpstart, unlike its Touch series |
| Wyze Lock Bolt v2 | Plug a power bank into the USB-C port, then enter your code. Keys are included too |
| Aqara U100 | USB-C emergency power, or the mechanical key, per the listing |
| Yale Assure Lock 2 Wi-Fi | Backup key included, per the listing |
| eufy C220 | Physical key. Two included |
| ULTRALOQ Bolt SE | Two mechanical keys included |
| August Wi-Fi Smart Lock | Your existing key still works from outside |
Wyze adds a warning: USB-C power is a short term fix to get in. Do not leave the lock on a power bank. Replace the batteries.
How long batteries are supposed to last
- Schlage Encode6 months
- eufy C2208 months
- Wyze Lock Bolt v28 months
- Aqara U1008 months
- ULTRALOQ Bolt SE18 months
- August Wi-Fi3 months
These are maker claims under the maker's idea of typical use. The August number comes from August's FAQ, which says battery life depends on how often the lock runs, bolt friction, WiFi signal and router settings. Owner reports for several of these locks are much shorter. See battery claims vs owner reports.
A plan that works
- Know where your key is. The key does you no good inside the house. Leave one with someone you trust or in a safe spot outside.
- If your lock has USB-C, keep a charged power bank and cable in the car.
- Keep a spare set of the right batteries in a drawer. The August takes two CR123 cells, per its FAQ. Most others here take AA.
- Fix a sticky bolt. A bolt that drags uses more power on every lock. Do the free throw check.
If a dead battery is your biggest worry, look at the locks with two backups on our shortlist. This page is general information, not security advice.