Sensor Battery, Charging, and Replacement

Battery life is generally 1-2 years for replaceable-battery Sensors, but cold environments and weak signal can shorten it. Select the section that matches your model. Do not open a rechargeable Sensor.

Rechargeable Sensors: ST3, ST4, ST5, ST6, ST9, ST10, and SW2

1. Open the charging-port cover.
2. Connect the Sensor with the Micro USB cable supplied with it.
3. Confirm that the red indicator turns on. This means the Sensor is charging.
4. Disconnect the cable when the red indicator turns off. The Sensor is fully charged.
5. Close the charging-port cover securely before returning the Sensor to service.

The App battery percentage is an estimate and may not refresh immediately. If it still shows the old value, place the Sensor near its Hub, trigger a fresh report with the Sensor button or pinhole, and check the App again.

If the red indicator never turns on, try reconnecting the cable and using another working USB power source. If it still does not turn on, contact support with the Sensor model, SN, and observed indicator state.

Replaceable batteries

ST7 and ST8: 9 V 6LR61

1. Turn the Sensor off.
2. Open the battery cover or compartment.
3. Remove the old 9 V 6LR61 battery and connect a new battery of the same type.
4. Close the cover and turn the Sensor on. ST7 beeps when it powers on; for ST8, turn the alarm switch to ON.

ST7 and ST8 connect directly to a phone. Keep the phone nearby when checking the battery or syncing data. ST8 can continue logging without the phone, but the phone must be nearby to view or synchronize stored readings.

MS1 and MS2: three AAA batteries

1. Open the battery cover.
2. Remove all three old batteries.
3. Install three new AAA batteries, matching the + and - marks. Do not mix old and new batteries or different brands.
4. Close the cover. Press Setup/Test for about 1 second to trigger a fresh report through the Hub.

MS1 and MS2 have external probes. Keep the Sensor body accessible and place only the probe in the cold area when possible. In a freezer, use batteries rated for low temperatures.

SS1, ST1, and ST2: CR2032 button batteries

These models use replaceable CR2032 button batteries. Open the rear housing with a plastic card, never a metal tool, and install a new CR2032 battery with the + side facing the circuit board. Do not force the housing.

After replacing a battery

Bring a Hub-connected Sensor close to its Hub and trigger a report with the Sensor Setup/Test button or pinhole. If the Sensor remains offline or its data does not update, follow Sensor Offline and Sensor Probe Disconnected.

The App battery display is an estimate. If it still shows the old value after a fresh report, wait for the next scheduled reading before replacing the battery again.