A dead lock usually announces itself — red light, a voice warning, or a keypad that ignores you — and the swap itself is the easy part. What gets people locked out is putting them back wrong. Four AA alkalines in one model, two CR123 lithiums in another, polarity flipped on one cell: the door doesn’t know or care that you were in a hurry.
How Do You Replace the Batteries Step by Step?
- Work from inside the house. A battery cover, faceplate, or slide-off compartment sits on the interior side.
- Open it. Some models press off by hand; others hide a small Phillips screw. If screws are involved, snug them when you close up — Master Lock’s electronic lock instructions say do not over-tighten.
- Pull out every old battery. Remove all of them, not just the one that looks weak.
- Insert the new set with the polarity marks matched exactly — plus to plus, minus to minus, per each cell’s diagram.
- Close and secure the cover or push the compartment back until it clicks.
- Test the lock.
If nothing happens, the polarity is the first thing to recheck.
Which Batteries Does Your Lock Actually Take?
The battery type is model-specific, and guessing wrong is the most common mistake. August’s own three lock generations split between lithium CR123 cells and standard alkaline AAs.
| Lock Model | Battery Type | Count |
|---|---|---|
| August Wi-Fi Smart Lock | Non-rechargeable CR123 lithium | 2 |
| August 3rd Generation Smart Lock | Non-rechargeable alkaline | 4 |
| August 1st Generation Smart Lock | Non-rechargeable alkaline | 4 |
| DigiLock deadbolt/deadlatch (one variant) | Premium alkaline AA | 4 |
| DigiLock deadbolt/deadlatch (other variant) | Premium lithium 123A | 4 |
| Philips EasyKey DDL801-5HBS | Alkaline AA | 4 (tray holds up to 8) |
Nuki’s Smart Lock puts its battery compartment on the bottom of the unit: press the small lever in the arrow direction, slide the compartment out, swap the cells, and push it back in. Check your model’s manual or support page before buying replacements, and if your lock is getting old, it may be worth comparing a newer unit against our tested battery-operated door lock picks before sinking more money into an aging one.
What Happens If the Batteries Die While You’re Locked Out?
A dead battery doesn’t have to mean a locksmith, but the emergency options differ by brand. DigiLock’s procedure covers a valid Manager Key that can be inserted and left in the key slot until the lock operates and the door opens.
Learn how your specific lock warns you before it dies. Whatever the signal looks like on your model, treat it as a deadline rather than a suggestion, and replace the cells promptly instead of waiting for the lock to give out entirely.
Two more habits keep you out of trouble. And recycle the spent batteries through a local program rather than tossing them in the trash.
FAQs
Do I have to remove the lock from the door to change batteries?
No. The battery cover, faceplate, or compartment sits on the interior side of the door, so the lock stays mounted while you swap the cells.
Can I use rechargeable batteries in a smart lock?
Stick with what the manufacturer specifies.
How often should door lock batteries be replaced?
Replace them as soon as the lock warns you — red flash, voice prompt, or app alert — rather than on a fixed calendar. Battery life swings with traffic, temperature, and radio use.
References & Sources
- DigiLock. “Replace Deadbolt or Deadlatch Lock Batteries.” Confirms in-place battery replacement, whole-set changes, polarity, and Manager Key emergency access.
- Nuki. “Smart Lock Batteries.” Documents the bottom-mounted battery compartment removal and reinsertion process.
- Kwikset. “Install / Replace Battery.” General manufacturer guidance for electronic lock battery servicing.