ADT's low battery article lists every sensor battery: the Door/Window Sensor takes one CR2; the Motion Sensor one CR123A; the Water and Temperature Sensor one CR123A; the Keychain Remote one CR2450; the Indoor Siren two CR123A; the Smoke and CO Detector three CR123A; the Smoke Detector three CR123A; the Heat Detector two CR123A; the Carbon Monoxide Detector two CR123A; and the Glass Break Sensor four CR123A.
The checks in more detail
The batteries in door and window sensors may have a shelf life of up to ten years, but in a device the expected life is up to two years, and heavier use shortens it, so ADT recommends changing all wireless sensor batteries annually or as your system directs. Before replacing, make sure the battery is seated properly. If the low battery message does not clear for more than 24 hours after replacement, delete and re-add the sensor. A motion sensor may just need cleaning, since residue from the pulled tab can reduce contact:
open the sensor, remove the battery and clean the positive side and the contact point with an alcohol swab until no marks remain. Beeping or a yellow Disarm button on the Base may accompany a low battery. Use fresh, matched cells. Write the change date on the inside of the cover so you know the age at the next warning. Cold garages and hot attics shorten battery life, so expect earlier warnings there. Keep spare batteries of each type in one labeled box.
ADT notes a shelf life of up to ten years for the door sensor battery but only up to two years in service, so old stock is not the problem, and a quick annual swap of all the sensors is the simplest routine. The keychain remote uses a CR2450, the siren two CR123A and the glass break sensor four, so spare batteries for a whole home fill a small drawer and are worth keeping labeled.
Differential
Likely causes of “ADT sensors and detectors has power or battery problems”, and how to tell them apart
- 1
An aging battery
What separates it The sensor beeps or shows a Low Battery message because the battery inside it is getting old
How to confirm Replace the battery with the exact type ADT lists for that sensor and check the message clears
- 2
A misseated battery
What separates it A low battery message appears even though the battery is new because it has been fitted badly
How to confirm Reseat the battery so it sits correctly against the contacts and check the polarity marks
- 3
A dirty contact
What separates it The low battery message persists after a new battery is fitted because the contacts are dirty
How to confirm Clean the battery contact with an alcohol swab and let it dry before you refit the battery
- 4
A message that will not clear
What separates it The message will not clear even after replacement, and the sensor still shows low battery in the app
How to confirm Delete the sensor and add it again after waiting 24 hours so the old status is cleared
- 5
Heavy use
What separates it The battery seems to run down far too fast because the sensor is triggered very often
How to confirm Expect earlier changes for sensors in busy areas, and consider a better position for the sensor
Before you touch a setting
Record this first — changing settings destroys the evidence
- The sensor and the battery type it uses
- The age of the battery that is fitted
- Whether the tab residue was cleaned
- How long it has been since the battery was last replaced
Try in this order
0 of 7 completedIdentify the sensor's battery
ReversibleIdentify the sensor's battery from ADT's list, since the Door and Window Sensor, Motion Sensor and others each take a different cell.
Reseat the battery
ReversibleReseat the battery and check the polarity marks, because a battery that is a little loose or the wrong way round gives a false low battery message.
Replace it
ReversibleReplace it with fresh, matched cells, using the exact type ADT lists, and do not mix old and new batteries in a sensor that takes several.
Clean contacts
ReversibleClean the contacts on a motion sensor with a swab and a little alcohol, and let them dry before closing the battery compartment.
Wait 24 hours
ReversibleWait 24 hours for the message to clear after a battery change, because the status can take a while to update.
Delete and re-add
ReversibleDelete and re-add the sensor in the app if the message persists after 24 hours, then test it in Test Mode.
Contact ADT
ReversibleContact ADT if the message will not clear after all of this, and give them the sensor type and the date you changed the battery.
Model-specific
What is true of this model and not of its siblings
- Coin and CR cells
- CR2, CR123A and CR2450 depending on device.
- Life
- Up to two years in use.
- Other models this page answers
- These steps also fit models Carbon Monoxide Detector, Indoor Siren, Live Light, Premium Door/Window Sensor, Smoke and Carbon Monoxide Detector, Smoke Detector, Water and Temperature Sensor.
Stop boundary
When this stops being a self-service repair
- !If the message persists, contact ADT through chat
- !If a battery has leaked, clean the compartment carefully and replace it with a fresh one
- !If the life is very short, check what keeps triggering the sensor and whether the position suits it
Evidence ledger
Sources behind this answer
Battery types and lives.
Motion sensor setup and use.
Base setup and placement.
Base LED patterns.
The company and its products.
Exact questions
Common questions
What does the Door/Window Sensor use?+
The Door and Window Sensor uses one CR2 battery, which is the small lithium cell you fit behind the cover of the sensor.
What does the Motion Sensor use?+
The Motion Sensor uses one CR123A battery, so keep a spare of that type at home for the next time it runs low.
What does the Glass Break Sensor use?+
The Glass Break Sensor uses four CR123A batteries, so replace all four together when its low battery message appears.
How long do batteries last in use?+
Batteries can last up to two years in use, though the life depends on how often the sensor is triggered and the temperature.
How often should I change them?+
ADT suggests changing sensor batteries annually, which is a sensible routine even when no low battery message has appeared yet.
Why does a low battery message persist?+
A low battery message can persist because of a dirty contact or a stale state in the app, rather than because the battery is really flat.
Can cleaning fix it?+
Yes, cleaning can fix it for motion sensors, since dust or film on the battery contacts causes a false low battery reading.
What does the Indoor Siren use?+
The Indoor Siren uses two CR123A batteries, so replace both together when they run low.
What does the Smoke and CO Detector use?+
The Smoke and CO Detector uses three CR123A batteries, so replace all three together when the low battery warning appears.