Why does not charge fitness bracelet Xiaomi Mi Band 4: a full analysis of problems and solutions

The Xiaomi Mi Band 4 fitness bracelet has become a hit with healthy lifestyle fans — compact, functional and with impressive battery life. But even such a reliable device sometimes fails: one of the most common problems is that the bracelet has stopped charging or charging is extremely slow. If your Mi Band 4 does not respond to the connection to the charger, does not show a charging indicator or discharges immediately after disconnecting from the network, do not rush to write it off.

In 80 percent of cases, the problem is solved without going to the service center, and it's enough to diagnose the cause correctly. In this article, we'll look at all possible scenarios, from trivial contamination of contacts to software failures, and give you step-by-step instructions for restoring performance. We'll focus on the hidden "chips" of Mi Band 4 firmware that can block charging after upgrades. If you've tried standard methods (reboot, contact cleaning) and they haven't worked, you'll find solutions for complex cases.

1. Checking of charger and cable

The first thing to rule out is a charging module malfunction. The Mi Band 4 uses a proprietary connector. USB-C Or microUSB!), so standard smartphone cables won't work, and even if the charge looks good, its internal contacts could oxidize or deform.

How to check:

• 🔌 Connect the bracelet to another charger (borrow from friends or buy a new one – the original is worth it). ~300₽).
• 🔍 Examine the charging connector for the presence of foreign objects (dust, fabric fibers) or traces of corrosion.
• 📱 Try charging the bracelet from another power supply (for example, from charging a smartphone with an output). 5V/1A adapter).
• 💡 Check if the charge indicator on the bracelet is on when you connect. If not, the problem is in the contacts or the board.

Note: Some users are confusing Mi Band 4 Mi Band 5/6 — If you accidentally used a charger from another model, it could have damaged the bracelet contacts.

2. Diagnostics of the bracelet contacts

The most common reason for not charging is contamination or oxidation of the contacts on the back of the bracelet, sweat, hand creams or dust on metal plazas, which blocks the transmission of current. Unlike smartphones, the Mi Band 4 contacts are not protected by rubber plugs, so they require regular cleaning.

How to clean contacts:

1. Remove the strap from the bracelet (carefully pull the lock on the back side).
2. Take a cotton swab soaked in isopropyl alcohol (not vodka! it leaves a plaque).
3. Carefully wipe all 4 pins (two large and two small) until shine. Don't push hard - they're soldered to the board!
4. Let the bracelet dry for 10-15 minutes before connecting to charging.

If there is no alcohol, you can use an eraser (washing gum) - it removes oxides well. But after that, be sure to blow the contacts with compressed air (for example, a can of keyboard cleaning).

Remove the strap|Drinking contacts with alcohol|Remove oxides with abscesses (if necessary)|Blow in compressed air|Let's dry for 15 minutes.-->

⚠️ Warning: Never use abrasive materials (paper sandpaper, metal brushes) or aggressive liquids (acetone, solvents) to clean, which will damage the protective coating of contacts and exacerbate the problem.

3. Software failures and resetting of settings

Sometimes the bracelet does not charge due to software errors, especially after updating the firmware or synchronization failure with the Mi Fit application. For example, a bug is known in firmware versions 1.0.9.14 and 1.0.9.26, when the bracelet “hangs” in low charge mode and does not respond to charging.

How to reset your settings:

1. Connect the bracelet to the charger and wait 30 seconds.
2. If the indicator does not light up, press and hold the touch button under the screen for 10-15 seconds until the vibration appears.
3. After resetting the bracelet should show the charging indicator (if the problem was in the software).

If the reset didn’t help, try a forced firmware update:

• 📱 Install the latest version of Mi Fit from Google Play or App Store.
• 🔄 In the app, go to Profile → Mi Smart Band 4 → Firmware update.
• 📲 If the update does not start, untie the bracelet in the settings and tie again.

4. Battery problems

The average battery life of the Mi Band 4 is 2-3 years when used actively. If the bracelet has become discharged in a few hours or does not hold charge at all, most likely, the battery is worn out.

• 🔋 The bracelet is charged only in a certain position (for example, if you press the contacts with your finger).
• ⚡ Charging is jerky: then the indicator appears, then disappears.
• 📉 The charge level drops from 100% to 0% in 1-2 hours.
• 🔥 The bracelet heats up when charging or working.

How to check the status of the battery:

If you decide to replace the battery yourself, consider: the Mi Band 4 uses a type battery. 3.7V 135mAh plug-in JST When soldering a new battery, be sure to check the polarity - the polarity will lead to instant failure of the power controller!

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Before replacing the battery, take a picture of the location of the plumes and contacts - in the Mi Band 4, it is easy to confuse the connectors of the vibration motor and the heart rate sensor.

Mechanical damage and moisture

Xiaomi Mi Band 4 has protection by standard 5ATM, This means resistance to splashes and short-term immersion to depths of up to 50 meters, but it does not guarantee protection against condensation inside the housing, which can occur after a long time:

• 🏊 Swimming in a pool with chlorinated water.
• 🚿 Prolonged exposure to hot water (shower, bath).
• 🌧 Rainfall with high acidity (in industrial areas).
• 💦 Acute temperature changes (for example, if you go from frost to a warm room).

Signs of moisture intrusion:

• 🌫 The appearance of fogging under the screen.
• 🔋 The bracelet is not charged, but the screen can be turned on by pressing.
• 📱 In the Mi Fit application, an error appears "Device is disabled".
• 🔊 Vibration disappears when notified.

What to do:

1. Remove the bracelet from the water immediately, do not press the buttons!
2. Wet the body with a dry napkin, remove the strap.
3. Place the bracelet in a silica gel container (box bags with shoes) for 24-48 hours.
4. Don’t use a hair dryer or microwave – it will hurt the charge!

⚠️ Attention: If the bracelet stopped charging after moisture hits, but the screen is working - this is a sign of corrosion on the board. In this case, self-repair is almost impossible: you need to wash the board in an ultrasonic bath and then solder the damaged tracks.

6. Alternative charging methods

If the original charger is lost or broken and the bracelet needs to be recharged, you can use non-standard methods. Importantly, these methods are suitable only for emergencies and can damage the bracelet if used incorrectly!

Method 1: Charging from USB-port

This will require:

• 🔌 USB-Type-A cable (from an old mouse or keyboard).
• 🔧 Two paper clips or thin wires.
• 📌 Isolation.

Instructions:

1. Take it apart. USB-cable and expose the red (+5V) black (GND) wire.
2. Attach them to the contacts of the bracelet (large areas — "+" and--- little data).
3. Secure the paper clips and seal it.
4. Connect to USB-port.

If the bracelet does not respond, change the polarity.

Method 2: Using a charging device from Mi Band 3

Although the Mi Band 3 and Mi Band 4 connectors are visually similar, they are not compatible in the wiring!

• 🔪 Carefully tuck the plastic case of charging with a knife.
• 🔧 Soak the wires so that "+" The "-" matched the contacts of Mi Band 4.
• 📏 Check the multimeter voltage (should be) ~5V).

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Never use a higher voltage power source to charge the Mi Band 4. 5V (It's like charging from tablets or laptops, and it's going to knock out the power controller of the bracelet!

7. When to contact the service center

If all of these methods didn't work, it's likely that the problem is a hardware malfunction, and here are some signs you should call a specialist.

• 🔥 The bracelet warms up when connected to charging.
• 💥 There was a smell of burning or smoke from under the body.
• 🛠 Mechanical damage to the board (cracks, chips) is visible).
• 📵 The bracelet is not defined by any device (even after resetting).
• 🔋 Battery swelled (bracelet body deformed).

Cost of repairs in service centers:

Official Xiaomi service centers in Russia:

• 📍 Moscow: list of addresses.
• 📍 St. Petersburg: Marshal Govorov str., 35 (in the shopping center "Gulliver").
• 📍 Regions: check by phone 8 800 775-66-88.

Before the service visit:

• 📄 Keep a check or warranty card (if the bracelet is warranty).
• 📱 Reset the bracelet to factory settings (to delete personal data).
• 🔍 Take a picture of the malfunction (such as a bloated battery or corrosion).

8.Preventing charging problems

To avoid charging problems in the future, follow these guidelines:

• 🧼 Clean the contacts of the bracelet and charger once every 2 weeks (coat wand with alcohol).
• 🚫 Do not wear the bracelet in a sauna, bath or under a hot shower – despite 5ATM, steam penetrates into the body.
• 🔋 Charge the bracelet to 80-90%, not 100% – this will prolong the life of the battery.
• 📱 Update your firmware regularly through Mi Fit, but don’t install the beta version.
• 🛡 Use a silicone case to protect against dust and moisture (worth it). ~200₽).
• 🔌 Do not leave the bracelet on charging for more than 2-3 hours - this can lead to overheating.

If you are actively exercising and sweating, remove the bracelet after exercise and wipe it with a dry cloth.Sweat contains salts that accelerate the corrosion of contacts.

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Keep the bracelet in a dry place with a bag of silica gel - this will prevent the formation of condensation inside the case with temperature changes.

FAQ: Frequent questions about charging the Mi Band 4