Smart home ecosystem owners often face the need to maintain their devices, and power comes first. When a smart thermometer stops transmitting data or a low-charge notification appears on the smartphone screen, the user faces the challenge of quickly replacing the battery. The right choice of battery is critical not only to restart the device, but also to ensure its long-term and stable operation over the next months.
Xiaomi’s product range and sub-brands like Aqara and Yeelight are extremely wide, causing confusion about the types of energy sources used: Some models require standard “finger” batteries, others are powered by compact “pills”, and still others have built-in lithium cells that can not be replaced without leakage. In this article, we will discuss in detail what battery is used in your model of the Xiaomi temperature sensor, how to replace and what to look for when buying a new battery.
Failure to replace or install a defective battery can lead to incorrect readings or complete failure of the device. It is important to understand the difference between chemical composition, voltage and dimensions, so as not to damage the electronics of the gadget. We have prepared a detailed guide to help you navigate the variety of models and avoid common errors in the maintenance of smart equipment.
The main types of power in Xiaomi devices
Xiaomi engineers use different approaches to power consumption depending on the form factor and tasks of the device. Compact humidity and temperature sensors are most often used lithium cells such as "pill" due to their small size and ability to produce stable voltage over time. Larger or energy-consuming models can meet standard cylindrical elements of the AAA or AA format. Understanding the size is the first step to successful replacement.
Special attention should be paid to the chemical composition of the battery. In most cases, lithium-manganese cells (denoted by the CR prefix) are used for sensors, which have a nominal voltage of 3 Volts. The use of alkaline analogs of the same size is unacceptable, since their voltage is only 1.5 Volts, which will cause the device to malfunction. It is also important to consider that some “tablets” may have different heights, which will physically prevent them from being installed in the compartment.
- 🔋 CR2032 — The most common type of tablet with a diameter of 20 mm and a thickness of 3.2 mm, used in most sensors Aqara and Xiaomi.
- 🔋 CR1632 — thinner (1.6 mm), which is sometimes found in compact key fobs or specific models of thermometers.
- 🔋 LR03 (AAA) — standard little finger battery with 1.5 volts, used in larger devices or control panels.
When buying, always pay attention to the manufacturer’s labeling. Original Xiaomi batteries often have the company logo, but in their characteristics they are no different from quality counterparts from Panasonic, Duracell or GP. The main thing is to avoid cheap nameless batteries that can quickly discharge or, worse, leak and oxidize the contacts of the device.
What battery is needed for the Aqara sensor and Xiaomi Temperature Humidity Sensor
The most popular model in the smart home ecosystem is the Xiaomi Mi Temperature and Humidity Sensor (often called a “square” or “round” depending on the generation). For the classic square version, as well as for the round version of the 2nd generation, the de facto standard is the CR2032 power element. This size ensures the device operates for 1-2 years depending on the frequency of the sensors polling and the quality of communication with the gateway.
However, there is a nuance with newer or more specialized models. For example, some versions of Aqara sensors with E-Ink display function also use CR2032, but can consume energy differently due to the energy consumption of the screen. The instructions for such devices always emphasize the need to use lithium batteries, since the display requires short-term but powerful current pulses that alkaline cells can not provide.
⚠️ Warning: Never try to shove in the compartment for CR2032 two smaller batteries (for example, two batteries) CR2016), Even if they fit in diameter, it will cause the sensor board to close and burn.
The replacement process in these models is usually as simple as possible. There is a small slot on the back of the device, in which you need to turn a coin or a special screwdriver. Once the case is opened, you will see a round battery fixed by a plastic holder. When removing the old battery, it is recommended to wipe the contacts with dry lilac cloth to improve conductivity.
Importantly, after the battery is replaced, the device may require re-pairing or resetting, although in most cases, the Aqara and Xiaomi sensors store the settings in memory and automatically connect to the gateway. If no automatic connection has occurred, use a pin to briefly press the reset button on the case.
Power for Xiaomi Bluetooth Thermometer 2 and other models
The Xiaomi Bluetooth Thermometer 2 (a color-coded E-Ink display) is fundamentally different, with a built-in lithium polymer battery that charges through a USB Type-C port on the side of the phone, and the question of “what battery” is transformed into “how to charge properly,” which doesn’t include external batteries.
For simpler models, such as the Mijia Smart Temperature and Humidity Monitor, which connect directly to a smartphone without a gateway, the CR2032 standard is also often used.However, always check the specification on the box or in the Mi Home app, as engineers can change the layout in new device revisions. In some rare cases, the CR2450 type size can be found, which is significantly thicker and has a larger capacity.
| Model of the device | Type of battery | Tension. | Exemplary resource |
|---|---|---|---|
| Xiaomi Temp Sensor (Square) | CR2032 | 3.0 In | 12-18 months |
| Aqara Temp Sensor (Circle) | CR2032 | 3.0 In | 18-24 months |
| Xiaomi Thermometer 2 | Built-in Li-Po | 3.7 V V | Up to 1 year (1 charge) |
| Yeelight Sensor | CR2032 | 3.0 In | 12 months |
If you're in doubt about the type of battery, look at the labeling inside the compartment. Manufacturers always specify the size and polarity required (which side to put "plus" up) directly on the plastic of the case. Ignoring these labels can lead to improper installation.
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Buy leakproof batteries, even expensive brands sometimes leak, and cheap ones almost always, which will save your smart sensor contacts from corrosion.
Instructions for safe replacement of the power element
The battery replacement process, despite its simplicity, requires a certain sequence of actions to be followed so as not to damage the fragile plastic latches of the case. Xiaomi devices are often assembled without screws, on tight latches that require careful handling. Incorrect opening can leave ugly marks on the body or break the mounts.
☑️ Checklist for battery replacement
First, you take the device in your hand and find the opening hole. Put a coin or a flat screwdriver in there and make a counterclockwise rotational motion. The lid should snap with the characteristic sound. Don't use excessive force; if the lid doesn't lend itself, try changing the angle of the tool. After removing the old battery, wait 5-10 seconds before installing the new one, which will allow the electronics to completely reset the residual charge.
When installing a new element, make sure that the side with the inscriptions and logo (usually a “plus”) looks up. In some Xiaomi sensor models, the battery can be closed with an additional insulating film that must be removed before first use, although it is usually not in replaceable batteries. After installation, press the lid tightly until you click around the perimeter.
⚠️ Attention: Don't touch the surface of the battery with your fat fingers. Fat spots can create a conductive track and speed up the self-discharge of the cell.
Once the device is assembled, the indicator (if any) may flash, signaling to turn on. In the Mi Home app, the charge status will not be updated immediately - this can take from a few minutes to an hour, since the sensors do not poll the gateway constantly, but at certain intervals to save energy.
Problems of autonomy and their solution
Sometimes users are faced with a situation where a new battery dies in a couple of weeks, which may indicate not a defective battery, but problems with the settings of the device or the environment. The low temperature itself reduces the capacity of the chemical elements, so the sensor installed on an unheated balcony in winter, will discharge faster.
Another reason for a quick discharge could be a bad signal from Zigbee or Bluetooth. If the sensor is far from the gateway, it has to constantly search for the network and transmit data at maximum power, which quickly depletes the resource. It is also worth checking the frequency of the survey: in the settings of some models, you can change the data interval, increasing it to save charge.
Effects of temperature on the battery
If the sensor continues to lose charge rapidly, try reconnecting it to the gateway by removing the old device from the application and adding it again. Sometimes a software failure causes the charge level to be incorrectly displayed or the device to stick in active data mode.
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The optimal distance between the sensor and the Zigbee gateway should not exceed 10 meters in line of sight, and the walls and metal structures significantly weaken the signal.