What battery is in the thermometer Xiaomi: a complete guide to types, replacement and nuances

Xiaomi thermometers are some of the most popular smart gadgets for health, but even they require periodic maintenance, and the main question that owners have is: what battery is used in the model, how to replace it correctly, and whether it can be saved on analogues. The type of battery depends not only on the accuracy of the measurements, but also on the life of the device.

In this article, we will take a look at all official Xiaomi thermometer models (including Mi, Mijia and Smartmi), specify the exact types of batteries, give step-by-step instructions for replacing and warn against common errors, and also give you an idea of how to extend the life of the battery and what to do if the the thermometer stopped turning on after replacement.

Xiaomi Thermometers and Their Batteries

Xiaomi produces several lines of thermometers, each using a different type of battery, and below is the current list of models (as of 2026) with the indication of batteries:

• 🔋 Xiaomi Mi Smart Thermometer (LYWSD02MMC) — CR2032 (3 V)
• 🔋 Mijia Bluetooth Thermometer (LYWSDCGQ/01ZM) — CR2032 (3 V)
• 🔋 Smartmi Air Detector (PM2.5 + temperature PM2.5-08) — 2×AAA (1.5 Every)
• 🔋 Xiaomi Mi Temperature and Humidity Monitor 2 (LYWSD03MMC) — CR2450 (3 V)
• 🔋 Xiaomi Mi Bunny Thermometer (children's model) VCL-BH319) — CR2032 (3 V)

Note that most models use the CR2032 lithium pill, but there are exceptions: for example, the Smartmi Air Detector is powered by AAA finger batteries, and the LYWSD03MMC has a more capacious CR2450. If you are not sure about the model, check the markings on the case or in the Mi Home app.

⚠️ Warning: Some sellers are positioning fakes under the Xiaomi brand with batteries LR44 or AG13. The original devices of the company are never equipped with alkaline "tablets" - only lithium (CR...). Check the labeling on the food element!

How to determine the type of battery in your thermometer

If you don’t know the exact model of the device, there are several ways to identify the power cell:

1. External inspection: Turn over the thermometer and find the battery compartment, usually marked on or near the contacts (e.g. CR2032).
2. Mi Home. Open the device card in the app, go to Settings → About the device. In some models, the type of battery is specified in the Specifications section.
3. Measure the diameter and thickness of the battery: 📏 CR2032: diameter 20 mm, thickness 3.2 mm 📏 CR2450: diameter 24.5 mm, thickness 5.0 mm

If the thermometer is disassembled and the battery is removed, compare it to a coin:

• 💰 CR2032 approximately equal to a 10-kopeck coin (Russia) or 1 eurocent.
• 💰 CR2450 closer in size to a 5-ruble coin or 2 euro cents.

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If the battery is leaky or covered with white coating, don't reuse it. Lithium cells can damage the contacts of the thermometer when the electrolyte leaks. Clean the compartment with alcohol and cotton swab.

Step-by-step instructions for replacing the battery

Replacing the battery in Xiaomi thermometers takes no more than 5 minutes, but requires care.

1. Open the compartment. Most models (like the LYWSD02MMC) have the lid locked with a latch, put it in a screwdriver with a flat stinger or the edge of a bank card, and apply a uniform force to keep the plastic mounts intact.
2. Remove the old battery. Use non-magnetic tweezers or apply your nail to the element. If the battery is boiling, don't pull it by force, but sway it slightly from side to side.
3. Install a new battery. Polarity is indicated in the compartment: + should match the marking on the housing. CR2032 and CR2450 "plus" is usually on top.
4. Close the lid. Make sure the sealing gum (if any) is flat. Click the lid until the characteristic click.

⚠️ Note: After replacing the battery, the Xiaomi thermometer may require re-synchronization with the Mi Home app:

1. Hold the power button (if any) for 5-10 seconds.
2. In the app, select Add Device → Thermometer.
3. Follow the instructions on the screen.

Which battery to choose: original vs analogues

Xiaomi’s original batteries (if they come with a kit at all) are often replaced by their counterparts.The main rule is: use only lithium cells labeled CR... Alkaline (LR...) or silver-zinc (SR...) batteries are not suitable – they have a different voltage and can damage the device.

Selection advice:

• 🛡️ Avoid no-name batteries – they often leak and have low capacity.
• 🔋 For long work, choose items marked Premium or Long Life.
• ♻️ Dispose of old batteries in special containers (in electronics stores or HOA).

Frequent problems after battery replacement and their solutions

Even with the right replacement of the battery, the Xiaomi thermometer can malfunction.

1. Thermometer not switched on

Causes and solutions:

• 🔌 Bad contact. Check if the battery fits tightly. Try to bend the contact plates slightly in the compartment.
• 🔋 A discharged cell. Even a new battery can be sat. Check it with a multimeter (voltage must be in place). ≥ 3 V for CR2032).
• 📱 Reset. Hold the reset button (if any) for 10-15 seconds. In models without a button, resetting the battery for 1 minute will help.

2.Indications are confused or unstable

Possible causes:

• 🌡️ Sensor contamination. Wipe the sensor with a soft napkin dipped in alcohol.
• 📶 Interference from other devices. Move the thermometer away from routers, microwaves, wireless speakers.
• 🔄 Calibration required. In the Mi Home app, check for firmware updates for the device.

3.The battery is running out fast

How to extend the service life:

• 📴 Turn off constant synchronization. In the thermometer settings in Mi Home, set the data update interval no more than 1 time in 10 minutes.
• 🌐 If the thermometer is near the hub (such as Xiaomi Gateway), the Bluetooth signal can be weakened.
• 🔌 Remove the battery for prolonged non-use, such as if the thermometer is not needed in the summer.

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If the Xiaomi thermometer flashes red after replacing the battery and doesn't sync, the Bluetooth settings are likely to have gone wrong. Solution: Remove the device from the Mi Home and add it again.

Where to buy a battery for the thermometer Xiaomi

The CR2032 and CR2450 are sold in most stores, but not all of them are suitable for precision devices.

• 🏬 Electronics chain stores: "Svyaznoy", "M. Video", "Eldorado" You can find premium batteries here (for example, Duracell or Energizer).
• 🛒 Supermarkets: "Pyaterochka", "Magnit", "Auchan" (brands) GP kodak).
• 🌍 Online: Wildberries (Search on Request "CR2032 Lithium") Ozon (branded kits, such as Panasonic CR2032 x5) AliExpress (cheap options, but the risk of running into a fake)
• 🔧 Specialized shops: "Chip and Deep", "Amperka" (for CR2450 and other rare types).

Average prices (for 2026):

• CR2032: 30–100 ₽ per unit (depending on the brand).
• CR2450: 80–150 ₽ piecewise.
• Set AAA (4 pcs: 150-300 ₽.

⚠️ AliExpress often sells batteries CR2032 10 ₽ They're usually fakes with low capacity (instead of the 220 mAh claimed, the real 100-150 mAh) and it's better to pay for a proven brand for a thermometer.

How to extend the life of a battery in a Xiaomi thermometer

The life of the battery depends not only on its quality, but also on the operating conditions. The following tips will help save on replacement:

1. Optimize your sync settings. In the Mi Home app, go to Device Settings → Update Rate and select a 30 minute or 1 hour interval. The less the thermometer transmits data, the longer the battery will live.
2. Use Power Saving Mode. Some models (e.g. LYWSD03MMC) have an option called Economy Mode. Turn it on in the settings.
3. Keep the thermometer in the right conditions. Avoid extreme temperatures (below -10°C or above +50°C). Lithium batteries discharge faster in heat.
4. Turn off Bluetooth if you don't need it. If the thermometer is only used for local measurements (without transferring data to the app), turn it off from Mi Home via Settings → Delete the device.

Interesting fact: Xiaomi thermometers with a CR2450 battery (such as LYWSD03MMC) have 30% lower power consumption than models with CR2032. If you plan to buy, give preference to devices with a more capacious battery.

FAQ: Frequent questions about batteries in Xiaomi thermometers