How to Replace the Battery in a Wireless Door or Window Sensor
When a wireless contact sensor stops reporting, it is almost always the batteries -- not the sensor. Here is how to swap them on a 2GIG Thin Door/Window Contact (DW10) and confirm the opening is back on watch.
The 2GIG Thin Door/Window Contact (model DW10-345) is one of the most common wireless sensors we install, and it runs on two CR2032 coin batteries. When you get a low-battery or tamper alert, put the system in test mode, press the tab to pop off the cover -- the screw-mounted base stays on the frame -- swap both CR2032 cells with the + sign facing out, close it up, and trip the sensor to confirm it is talking to the panel again.
Key Takeaways
- 1A low-battery alert points to the coin cells inside the sensor, not a fault with the sensor itself
- 2The 2GIG DW10 uses two CR2032 lithium coin batteries -- replace both at the same time, not one
- 3You do not remove the sensor from the wall -- the base stays screwed to the frame and only the cover comes off
- 4Orientation matters: both batteries seat with the + sign facing out
- 5After the swap, put the system in test mode and trip the sensor to confirm it is reporting to the panel
A wireless contact sensor has one job: tell your system when a door or window opens. So when one stops reporting or throws a low-battery alert, it is easy to assume it has failed. Usually it has not. The coin batteries inside have just run down.
This guide covers the 2GIG Thin Door/Window Contact -- model DW10-345 -- one of the most common sensors on the systems we install and service. A sensor with dead batteries is a door or window you are no longer watching, so it is worth acting on quickly. The fix takes a few minutes and two inexpensive batteries. Here is how we do it.
What you need
Two fresh CR2032 coin batteries and a small flathead screwdriver. The DW10 takes two Panasonic CR2032 lithium cells, or an equivalent lithium battery. Use fresh cells from a sealed pack and replace both together. Before you open anything, put your panel in test mode or disarm the system -- the sensor has a cover tamper, and opening it on a live system can trip the alarm.
Step 1: Put the system in test mode
From your panel, put the system into sensor test mode (or at minimum, disarm it). This keeps the cover tamper from setting off the alarm or sending a signal to your monitoring center while you work. It also sets you up to verify the sensor at the end without leaving the panel.
Step 2: Pop off the cover
You do not take the sensor off the wall. The base is screwed to the door frame and stays put. Press the tab on the end of the case to release the cover and lift it away from the base. That is the part you open to reach the batteries.
Step 3: Remove both old batteries
Inside the cover you will find two coin batteries held by a metal clip and a pair of black plastic edges. To free each one, slide the tip of a small flathead screwdriver into the slot between the metal clip and the battery, then twist the screwdriver slightly while holding back one of the plastic edges. The battery pops loose. Do the same for the second cell.
Step 4: Seat two fresh batteries -- + sign facing out
This is the step to slow down on. Set each new CR2032 in with the + sign facing out, away from the sensor body, so the printed side is visible. Put a cell in backwards and the sensor will not power up -- and you will be back here thinking it is dead when it is only reversed. Seat both cells the same way before you close it.
These are lithium batteries. Handled improperly, they can generate heat, rupture, or catch fire, so do not puncture, crush, short, or force them. Keep new and used cells away from children -- if one is swallowed, seek medical help immediately. Do not throw them in the household trash; dispose of them per your local regulations. California residents: this product contains a coin cell battery with perchlorate material, which may require special handling.
Step 5: Close it up and confirm it is reporting
Snap the cover back onto the base until it seats. Then confirm the sensor is talking to the panel: with the system in test mode, hold the magnet next to the alignment mark on the side of the sensor and pull it away, and listen for the panel or keypad to beep. You want to see the sensor register and verify its RF communication with the panel. If it reports cleanly, you are done. If it will not, that is the point to flag it for service rather than guessing.
One note on mounting
If you ever remount the sensor, keep the two parts in their correct spots: the sensor body goes on the door frame, and the magnet goes on the moving door. The two work as a pair, and the alignment mark on the side of the sensor is what the magnet needs to line up with. Swap those positions or set them out of line and the sensor can read as open when the door is shut.
Watch it done
If you would rather see the swap in motion, this short walkthrough covers the same steps end to end.
Usually a sensor that stops reporting isn't broken. It's two dead coin batteries -- and a few-minute fix.
Your Checklist
- Confirm the battery type -- the 2GIG DW10 takes two CR2032 lithium coin cells
- Put the panel in test mode (or disarm) before opening the cover -- it has a tamper switch
- Replace both batteries at once with fresh cells, + sign facing out
- Leave the screw-mounted base on the frame -- only the cover comes off
- Trip the sensor and verify RF communication with the panel before you walk away
- Note the date you replaced them so you have a rough sense of when the rest are due
Common Mistakes to Avoid
Replacing only one of the two batteries
The DW10 runs on two CR2032 cells, not one. Swap in a single fresh battery next to a dead one and it will be back on the low-battery list in no time. Replace both together with fresh cells from a sealed pack.
Installing a battery backwards
Both cells seat with the + sign facing out, away from the sensor body. Flip one and the sensor never powers up -- which reads exactly like a dead sensor. Check orientation on both before you close the cover.
Trying to pry the whole sensor off the frame
You do not remove this sensor from the wall to change the batteries. The base is screwed to the frame and stays there. Press the tab on the end of the case and only the cover comes off.
Getting the sensor and magnet reversed on remount
The sensor body belongs on the door frame; the magnet belongs on the moving door. Reverse them, or set them out of line with the alignment mark, and the sensor can read as open when the door is shut.
Skipping the panel check
Fresh batteries in the cover is not the same as a sensor the panel can hear. Put the system in test mode, trip the sensor, and confirm it reports before you consider the job done.
Frequently Asked Questions
What battery does the 2GIG DW10 sensor take?
Two CR2032 lithium coin batteries -- the manual specifies Panasonic CR2032 or an equivalent lithium cell. It is a common size you can find at any hardware store, pharmacy, or online. Replace both cells at the same time rather than just the one that reads low.
Do I have to take the sensor off the wall to change the batteries?
No. The base is screwed to the door frame and stays mounted. You only remove the cover -- press the tab on the end of the case and it lifts off the base. That is the part that holds the batteries.
Do I need to re-program the sensor after changing the batteries?
In most cases you do not need to re-add it, but you should verify it afterward rather than assume. Put the system in test mode, trip the sensor, and confirm it is programmed and communicating with the panel by RF. If it never reports after fresh, correctly seated batteries, then it may need to be re-added -- and that is worth a call.
Will the alarm go off when I open the sensor?
It can. The DW10 has a cover tamper, so opening it while the system is armed -- or in some setups even while disarmed -- can trip an alert or signal your monitoring center. Put the system in test mode before you start and you avoid setting anything off.
Are the batteries safe to handle and toss in the trash?
They are lithium cells, so handle them with care -- do not puncture, crush, or short them, and keep new and used batteries away from children. Do not put them in your household trash. Dispose of them according to your local regulations, and note that in California these coin cells carry a perchlorate handling notice.
Related Services
Managing a building full of sensors and tired of chasing low-battery alerts?
With a PAXCare plan, we keep an eye on device health and handle the maintenance before a dead battery turns into a blind spot. Licensed in NY and NJ.