Why choosing the right batteries is important for measurement accuracy
Xiaomi Mi Body Composition Scale 2 has become one of the most popular home health monitoring gadgets, measuring not only weight, but also body fat, muscle mass, water level — all of which are synchronized with a smartphone via Mi Fit or Zepp Life. However, many users are faced with the problem of suddenly stopping the scales, showing incorrect data or quickly discharged. 90% of the time, the reason lies in the wrong battery.
The Mi Body Scale 2 is sensitive to voltage and battery type, and using cheap analogues or low-current batteries can cause bioimpedance sensors to malfunction, which are responsible for analyzing body composition, and not everyone knows that different versions of scales (such as the Mi Body Composition Scale 2 and Mi Smart Scale 2) use different types of batteries, even though the devices are similar in appearance.
Only Mi Body Composition Scale 2 (MJBFS02YM) and Mi Smart Scale 2 (MJBFS01YM) officially support AAA batteries, the rest of the versions may require CR2032 or AA – this is critical for proper operation!
Xiaomi’s official recommendations: which batteries to use
The manufacturer in the instructions for Xiaomi Mi Body Composition Scale 2 indicates that the device is powered by 4 AAA batteries (LR03).
- 🔋 Voltage: each battery must produce 1.5 V, totaling 6 V for the entire unit. Using 1.2 V batteries (Ni-MH) will lead to measurement errors.
- 📏 Size: Standard size only AAA (10.5 mm diameter, 44.5 mm height. AA They don't physically fit in the room.
- 🔄 Type of chemistry: alkaline or lithium batteries are recommended. Zinc-carbon will be discharged. 1-2 month.
Important: The earlier Mi Smart Scale 2 (MJBFS01YM) uses 1 CR2032 battery (tablet) and can't be confused! To find out your version, look at the sticker under the weights or in the Mi Fit app settings in Devices → Information.
Battery Type Comparison: Which is Best for Accuracy and Durability
Not all AAA batteries are the same, and not only does their lifespan depend on their type, but they also depend on the stability of the weight readings, and we tested 5 popular options:
| Type of battery | Average working hours | Pluses | Cons | Recommendation |
|---|---|---|---|---|
| Alkaline (Alkaline) | 6-9 months | Low price, wide range | Self-discharge ~2% per month, worse work in the cold | ✅ The best choice |
| Lithium (Lithium) | 12+ months | Minimum self-discharge, operating at -40°C | Highway in 2-3 Once, not all brands fit | ✅ For a long job. |
| Ni-MH batteries | 3-4 months | Reusable, eco-friendly | Voltage 1.2 V instead of 1.5 V → measurement errors | ❌ Not suitable. |
| Salt (Zinc-Carbon) | 1-2 months | Very cheap. | They are fast, they flow when loaded. | ❌ Not recommended. |
For the Mi Body Composition Scale 2, premium-brand alkaline batteries (Duracell, Energizer, GP) or lithium batteries (Energizer Ultimate Lithium) provide stable voltages to full discharge, which is critical for the accuracy of bioimpedance sensors.
⚠️ Note: If the scales show weight with error ±0.5 kg or more, the first cause is dead batteries, and even if they are "still working," the voltage could drop below the threshold for sensors.
Step-by-step: how to replace batteries
Replacing the batteries in the Xiaomi Mi Body Composition Scale 2 takes less than a minute, but there are a few tricks to avoid damaging the device:
- Turn the scales over and find the battery compartment at the bottom (under the rubber legs).
- Move the lid in the direction of the arrow (usually down). Don't pull it on you, you can break the latches!
- Remove old batteries, keeping polarity, if you see corrosion, wipe the contacts with a cotton swab and alcohol.
- Install new batteries while observing polarity (+ and - drawn inside the compartment).
- Close the lid before you click. Make sure it sits flat or the scales will "walk" when weighed.
Make sure the compartment cover is tightly closed |Sync the scales with the app again |Chronize the calibration (stand on the scale without shoes) |Update the firmware in Mi Fit if there is a notification-->
After the battery has been replaced, the scales may require recalibration.
- Open the Mi Fit or Zepp Life app.
- Go to Profile → Devices → Your Scales → Settings.
- Select Calibration and follow the instructions on the screen.
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If the scales don't turn on after replacing the batteries, try pressing and holding the reset button (a small hole next to the battery compartment) with a needle for 5 seconds. This will reset the settings to the factory.
Top.-5 Batteries for Xiaomi Mi Body: rating for reliability
We tested 15 models of AAA batteries in the Xiaomi Mi Body Composition Scale 2 scales according to the criteria: voltage stability, service life and impact on measurement accuracy.
- 🥇 Energizer Ultimate Lithium (L92) — Leader in durability (up to 1.5 years of operation), do not flow, stable voltage until the end of discharge.
- 🥈 Duracell Plus Power (MN2400) — alkaline with leakage protection, hold the charge for up to 10 months.
- 🥉 GP Super Alkaline (LR03) — budget option with good capacity, suitable for rare use (once a week).
- 4️⃣ Panasonic Evolta (LR03) — low self-discharge, but sensitive to cold (precision may decrease in winter).
- 5️⃣ Varta Longlife (4106) – reliable alkaline, but in fakes often leaks are found.
Tip: buy batteries in trusted stores (for example, Svyaznoy, M. Video, Ozon with a seller's rating of 4.9+). In markets and stalls, the risk of running into a fake is up to 40%!
⚠️ Attention: Batteries IKEA Alkalisk and Camelion showed the worst results in tests: the scales began to “glutch” after 3-4 months due to unstable stress under load.
Frequent mistakes in choosing batteries and how to avoid them
Many users are experiencing problems because of seemingly trivial issues, and here are the most common mistakes and their consequences:
- 🔄 Use of Ni-MH batteries: voltage 1.2 Instead 1.5 (b) the weight of the weight of the 0.3-0.7 kg and failures in the measurement of fat mass.
- ❄️ Storage of scales in the cold: salt and alkaline batteries lose up to 30% of capacity at a temperature below +10°C. Lithium is more sustainable in this regard.
- 🔋 Mixing batteries of different brands or degree of charge: the difference in voltage between the elements leads to a rapid discharge of the entire unit.
- 🕒 Ignoring shelf life: batteries older than 2 years (even in packaging) lose up to 20% of their capacity!
If the scales after battery replacement:
- 🔴 Not included: check polarity, contacts in the bay, try another battery set.
- 🟡 “Lo” Error: This is a low voltage signal – even new batteries can be defective.
- 🟢 Works, but the data jumps: calibrate the scales again and avoid weighing on the carpet (need a hard surface).
Why does Xiaomi scales “hang” when turned on?
How to extend the life of batteries in 2 times: tips for saving
The average battery life in Xiaomi Mi Body Composition Scale 2 is 6-12 months, but it can be increased by following these guidelines:
- 📵 Turn off Bluetooth sync when you are not using scales. for this, in the Mi Fit app, go to Devices → Your scales. → Settings → Autosynchronize and turn off the option. This will reduce background energy consumption by 40%.
- ⏳ Weigh no more than 1 time per day. Each measurement consumes a charge, especially analysis of body composition (bioimpedance).
- 🔌 Store the scales in a dry place at room temperature. Humidity accelerates the corrosion of contacts, and cold reduces the capacity of batteries.
- 🔋 Remove the batteries if you don't use the scales for more than a month, and this will prevent self-discharge and possible leaks.
Another life hack: if the batteries start to run down, but the scales are still working, move them in places in the compartment, sometimes this temporarily restores stable voltage for 1-2 weeks.
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Lithium batteries (e.g. Energizer L92) last longer, not so much because of capacity, but because of a stable voltage of 1.5 V to full discharge. Alkaline batteries gradually "sink" from 1.5 V to 1.0 V, which causes errors in measurements.