If your SensorPush sensor stopped working after you replaced the battery, it's typically due to one of two things: battery polarity (the direction the battery is facing) or battery quality.
Check the Battery Orientation First
The single most common reason a sensor won't work after a battery change is that the battery was installed with the wrong orientation. All SensorPush sensor models, including the HT1, HT.w, and HTP.xw, require the battery to be installed with the correct positive (+) and negative (-) orientation. If the battery is in backwards, the sensor simply won't power on and could be damaged.
For the HT1 sensor, the positive (+) side of the battery should face away from the circuit board. There's a small marking inside the battery compartment that indicates the correct orientation. For the HT.w and HTP.xw sensors, there's a diagram printed near the battery cap showing which way the battery should face. The positive (+) side should face up (toward you when you're looking at the battery cap).
It's worth double-checking this even if you're confident you got it right the first time. We've seen countless cases where customers were certain they had the orientation correct, only to discover upon closer inspection that it was actually reversed.
Make Sure You're Using a Quality Battery
Another common issue involves the quality of the replacement battery itself. We've noticed that some battery brands aren't reliable, particularly those from less-established manufacturers or third-party sellers on online marketplaces. Counterfeit batteries are surprisingly common, especially on sites like Amazon where third-party sellers mix their inventory with genuine products.
The most reliable battery brands we recommend are Panasonic, Murata, Duracell, and Toshiba. For purchasing, we suggest reputable electronics suppliers like DigiKey, Mouser, or Grainger. These sources sell genuine components and have quality control measures in place.
If you're unsure about your battery's quality, try replacing it with one from a known reliable brand and source. Many cases of sensors that "won't work after battery replacement" turn out to be caused by defective or counterfeit batteries rather than any problem with the sensor itself.
Re-Add the Sensor to Your App
After a battery has been depleted for a while, the sensor's internal state can sometimes get out of sync with your phone or Gateway. Even if you've confirmed the battery orientation is correct and you're using a quality battery, the sensor may need to be re-added to your app.
You don't need to delete the sensor from your app first. Simply go to the main "Devices" screen in the SensorPush app, tap the add button, and select "Add Sensor." Hold the sensor against your phone screen over the moving image as you did when you first set it up. After a few moments, the app should detect and reconnect to the sensor.
If the standard re-add process doesn't work, try deleting the sensor from your app first, then add it again as if it were brand new. To delete, tap on the sensor from the device list, scroll down to the bottom of its details screen, and look for the delete option.
Enable Bluetooth in the App
One thing that catches some customers off guard: if you're using a Gateway for remote monitoring, the SensorPush app automatically turns off its Bluetooth scanning to save your phone's battery. This means even if you're standing right next to the sensor, the app won't detect it unless you've re-enabled Bluetooth in the app's settings.
To check this, open the app and tap the settings button in the top-left corner of the main "Devices" screen. Look for the Bluetooth toggle in the Configuration section and make sure it's turned on. Once the sensor is reconnected, you can turn this off again if you prefer to rely solely on your Gateway.
Check the Battery Voltage
If your sensor is connecting but behaving strangely, it's worth checking whether the replacement battery actually has sufficient charge. Even new batteries can sometimes be defective or have lost charge from sitting in storage too long.
To check the battery voltage: from the home screen with "Devices" at the top, tap on your sensor to open its details screen. Do a pull-down gesture to refresh and get the latest reading. Then scroll down to the bottom where you'll see "Battery Voltage." A healthy, new CR2477 battery should show around 3.0V. Anything less than 2.3V means the battery is too low and needs to be replaced. If your brand-new replacement battery is showing low voltage, it's likely a defective or counterfeit battery.
When It Might Be a Hardware Issue
If you've confirmed the battery orientation is correct, tried a fresh quality battery from a reputable source, and gone through the re-pairing process, but the sensor still won't connect or read temperature and humidity, there may be a hardware issue with the sensor itself.
Sensors can occasionally develop defects, especially if they've been exposed to extreme conditions, moisture (for non-water-resistant models), or if the battery was left depleted for an extended period. In these cases, please contact us at support@sensorpush.com and we'll be happy to help.
Related Resources
For step-by-step battery replacement instructions including images and a video guide, see: How long will the battery last? And how do I change the battery?
For more information about re-connecting after a battery change, see: I changed the battery in my sensor, so why is my Gateway or phone not picking it up?