What battery is in the thermometer Xiaomi Mijia: a complete guide to choosing and replacing

Xiaomi Mijia series thermometers LYWSD (for example, models LYWSD03MMC or LYWSD02) They've become popular because of their accuracy, compactness and integration with the Mi Home ecosystem, but even such a simple device requires periodic maintenance, primarily a replacement of the battery. The question “what battery in the thermometer Xiaomi Mijia” arises from users not by chance: the correct choice depends on the stability of the sensor, the frequency of replacement and even the accuracy of readings.

In this article, we will examine not only the type of battery used in various Mijia thermometers, but also the nuances of its replacement, the signs of discharge, and give recommendations for choosing analogues. We will focus on common errors that can lead to device failure or malfunction. If you are faced with the thermometer stopped synchronizing with your smartphone or shows incorrect data, the problem may lie in the power source.

Before we get to the practical tips, note that, despite their simplicity, Xiaomi thermometers are sensitive to battery quality. Using cheap or fake batteries can reduce the life of the device by 2-3 times, so it is important not only to know what battery you need, but also where to buy it.

Official models of Xiaomi Mijia thermometers and their batteries

The Mijia range of thermometers includes several popular models, each with its own power characteristics, and the table below is a table with the current data for 2026:

As you can see from the table, most models use a type battery. CR2032 — This is a standard lithium power cell with a diameter of 20 mm and a thickness of 3.2 mm. LYWSDCGQ apply CR2450 (24.5 mm diameter, which is due to the increased capacity and higher power consumption of the sensor. CR2032 instead CR2450 will lead to unstable operation of the thermometer due to insufficient voltage under load.

If you are not sure about your device model, check it in the Mi Home app:

1. Open the app and go to the Devices section.
2. Select your thermometer and click on the three dots in the upper right corner.
3. In the Settings menu, find the Information item – the exact model will be indicated there.

How to determine that the battery in the thermometer Xiaomi has gone down

Lithium batteries CR2032/CR2450 They don't discharge instantly, they drop gradually. But Xiaomi Mijia thermometers often stop working properly before they're completely discharged. Here are key signs that the battery needs to be replaced:

• 🔋 The thermometer is no longer synced with the Mi Home app (data is not updated or comes with a delay).
• 📉 Temperature/humidity readings become unstable (jumps without objective reasons).
• 🔄 The device periodically “disappears” from the network and appears again only after a restart.
• 🚨 On the screen (if any) appears low charge icon or flashing indicator.
• 🔌 The thermometer is not switched on after pressing the reset button (if it is provided in the model).

Please note: if the thermometer LYWSD03MMC I started to show false data (for example, temperature). +100°C or humidity 0 percent, the problem may not be the battery, but the sensor damage. In this case, try resetting the device to factory settings through the Mi Home app. → Reset).

⚠️ Attention: Some users confuse battery discharge with Bluetooth module problems. If the thermometer does not connect to the phone, first check whether Bluetooth is on on the smartphone and whether the device is within range (up to 10 meters without obstacles).

For accurate diagnosis, you can measure the battery voltage with a multimeter:

1. Carefully remove the power element from the thermometer.
2. Connect the multimeter probes to the battery contacts (polarity is not important).
3. If the voltage is below 2.8 V, it is time to replace the battery.

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Before replacing the battery, take a picture of its location in the compartment – this will help to avoid errors when installing a new one (especially important for models with non-standard polarity).

Step-by-step instructions for replacing the battery in Xiaomi Mijia

Replacing the battery in Xiaomi thermometers is a simple procedure, but requires care. Below is a universal instruction, suitable for most models (LYWSD03MMC, LYWSD02 etc.).

Screwdriver cross (for models with screws)|Plastic blade or mediator|New battery CR2032/CR2450|Alcohol wipes (for cleaning contacts)|Multimeter (optional, to check the voltage)

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Step 1. Open the thermometer body

In most Mijia models, the back cover is mounted on the latches to remove it.

1. Place the thermometer on a flat surface with the face down.
2. Insert a plastic blade into the gap between the body and the cover (start with the corner).
3. Carefully lid the lid as you move around the perimeter. Avoid excessive effort - the plastic is fragile!

In models LYWSDCGQ The cover can be additionally fixed with a screw - it must be twisted with a cross screwdriver.

Step 2: Remove the old battery

When the lid is removed, you'll see a battery compartment, and notice the polarity of the battery compartment (usually marked on the body «+» and «−»). To extract the power element:

1. Tap the battery with your nail or plastic spatula on the side.
2. If it is “feeling”, do not pull force – gently shake it from side to side.

⚠️ Warning: Do not use metal objects (knives, screwdrivers) to remove the battery - this can cause a short circuit and damage the thermometer board.

Step 3. Install a new battery

Before installing the new battery:

1. Wipe the contacts in the compartment with an alcohol napkin (this will remove the oxides and improve contact).
2. Check that the polarity of the new battery matches the marking on the case.
3. Carefully insert the power element before clicking (it should fit tightly to the contacts).

For models LYWSD03MMC After the battery is replaced, you may need to reset (press the button for 5 seconds).

Step 4. Gather the hull.

Make sure all the latches are in place and the cover is tightly attached to the body.

1. Check if the battery is installed correctly (turn it over).
2. Make sure your contacts are not contaminated.
3. Try resetting the device through the Mi Home app.

Which battery to choose for Xiaomi Mijia: original vs analogues

The quality of the battery not only determines the life of the thermometer, but also the stability of its operation. CR2032 They can discharge quickly, they can leak, they can't provide enough voltage under load:

• 🔝 Original Xiaomi batteries – sold bundled with some models of thermometers or separately (article) MJBAT01CR). Guaranteed compatible, but more expensive than analogues.
• 🔋 Duracell CR2032 — reliable option with a long service life (up to 1.5 years in thermometer.
• 🔋 Energizer CR2032 — Good balance of price and quality, suitable for models LYWSD02 and LYWSD03MMC.
• 💰 Maxell CR2032 — budgetary equivalent, but may last less (about 8-10 months).
• 🔋 Panasonic CR2450 — optimal choice for the model LYWSDCGQ (high capacity, stable voltage).

Avoid unnamed or suspiciously low-priced batteries, which often have understated capacity and can damage thermometer contacts when leaking, and it is also not recommended to use rechargeable versions. CR2032 — They have a lower voltage (2.4 V instead of 3 V), which will lead to incorrect operation of the sensors.

If you live in a cold climate, you should prefer batteries labeled "for extreme temperatures" (e.g. Duracell Extreme or Energizer Ultimate Lithium) that are better able to hold their capacity in sub-zero temperatures, which is the case for street thermometers. LYWSDCGQ.

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For maximum life of the thermometer, use batteries with lithium technology (Li-MnO2) — They hold the charge longer and are less prone to self-discharge.

Frequent Battery Replacement Mistakes and How to Avoid Them

Even a simple procedure like replacing a battery can be problematic, if you don't take into account some nuances.

• 🔄 The wrong polarity, if you confuse it «+» and «−», The thermometer won't turn on. Always check the markings on the case.
• 🔋 Use of old batteries -- even if the battery had been in the package for a few years, it could have decreased in capacity.
• 🛠️ Contact damage – when removing the battery with metal objects, you can scratch the board, which will lead to poor contact.
• 💧 Ignoring the leak – if the old battery leaks, its remnants must be completely removed with alcohol, otherwise the new one will quickly discharge.
• 📱 No reset after replacement – some models require a reboot (press the button for 5-10 seconds).

Pay special attention to sealed models (e.g. ClearGrass for aquariums), when disassembling such devices, it is easy to damage rubber seals, which will lead to moisture getting inside. If the thermometer is no longer waterproof after replacing the battery, use silicone sealant to restore protection.

⚠️ Note: If the thermometer is replaced after the battery is replaced LYWSD03MMC He started to show the temperature with an error. ±5°C, most likely, the sensor was damaged during assembly, in which case the device will have to be replaced, the sensors in these models are not repaired.

Another common problem is that the thermometer doesn't connect to the Mi Home after the battery is replaced.

1. Remove the device from the application (Settings) → Remove the device).
2. Reset the thermometer to factory settings (press the button for 10 seconds before the indicator blinks).
3. Add it again through Add the device → Dashi → Thermometer.

Where to buy a battery for Xiaomi Mijia: proven sources

The quality of the battery directly affects the performance of the thermometer, so it is important to buy it in safe places.

• 🛒 Xiaomi’s official store – original batteries MJBAT01CR, But there are often supply disruptions.
• 🛒 AliExpress – Look for sellers with a rating above 98% and reviews of original batteries (e.g. Duracell or Energizer "OEM" — It's more often a fake.
• 🛒 Local electronics – in stores such as “Svyaznoy”, “M. Video” or “Eldorado” usually have certified batteries CR2032 famously.
• 🛒 Pharmacies – sometimes sell batteries for medical thermometers that are suitable for Xiaomi Mijia.
• 🛒 Amazon/eBay — If you order from abroad, choose sellers with a return guarantee (in case of marriage).

The cost of the original Xiaomi battery is about 200-300 rubles, while Duracell CR2032 It will cost 100-150 rubles apiece. Buy "sets of 10 pieces" for 200 rubles is impractical - most likely, these are low-quality analogues with a short service life.

When buying, pay attention to:

1. Production Date: Lithium batteries lose up to 2% of their capacity per year, even in packaging.
2. Packaging – Original Duracell or Energizer batteries have holographic stickers and autopsy protection.
3. Voltage - should be exactly 3 V (check with a multimeter in case of doubt).

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If you use Xiaomi thermometers frequently (for example, to monitor the temperature in multiple rooms), stock up the batteries and store them in a dry place at room temperature.

How to extend the battery life in the thermometer Xiaomi

Average battery life CR2032 Xiaomi Mijia thermometer is about a year old, but if you use it properly, you can increase it to 1.5-2 years:

• 📶 Reduce the data rate – in the Mi Home settings, set the update interval no more than 1 time in 10 minutes (default – 1 time in 2 minutes.
• 🔌 Turn off the thermometer for prolonged non-use – if you go on vacation, remove the battery (especially important for street models).
• 🌡️ Avoid extreme temperatures – at temperatures below −10°C or higher +50°C battery discharges faster.
• 🔋 Use low-discharge batteries like Panasonic CR2032 or Varta Longlife.
• 📵 Keep the thermometer in the area of strong reception Bluetooth – if the signal is weak, the device spends more energy on repeated attempts to transfer data.

For display models (LYWSD03MMC) You use extra energy to light up, and if you don't need a screen, you can turn it off in the Mi Home settings. → Display. → Turn off the backlights. That'll extend the battery life by 20 to 30%.

If the thermometer is used outside (for example, LYWSDCGQ), Protect it from direct sunlight and precipitation, overheating and moisture accelerate the discharge of the battery, and you can use a silicone case to provide additional protection.

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Optimal operating mode for maximum battery life: data update interval - 10 minutes, screen illumination is turned off, operating temperature - from 0°C +40°C.

FAQ: Frequent questions about batteries in thermometers Xiaomi Mijia