Xiaomi Mi Band 4 remains one of the most popular fitness bracelets even years after its release – its reliability, functionality and affordable price attract millions of users. However, many face problems when charging the device: the bracelet is not detected, it charges too long or does not turn on after connecting to the network. In this article, we will analyze all the nuances of charging, from choosing the original cable to diagnosing faults, and give expert recommendations for extending the battery life.
The Mi Band 4 design involves a magnetic charger that attaches to the back of the case, but even here there are pitfalls: unoriginal cables can damage the contacts, and the wrong position of the bracelet at the docking station leads to slow charging, and we tested various scenarios and collected checklists, compatibility tables and answers to frequent questions to make your bracelet work like a new one.
1.What is the right charger for Xiaomi Mi Band 4?
Original charger for Mi Band 4 has a marking MDY-08-EM And it comes with a bracelet. It's a small magnetic module with a USB-If you have lost your native cable, it is important to choose a certified replacement to avoid compatibility issues.
There are cheap analogues on the market, but they often have inadequate voltage (5V/0.5A instead of 5V/1A), which leads to slow charging or overheating of the battery.
- 🔹 Mi or Xiaomi logo on the docking station body.
- 🔹 Magnets firmly fix the bracelet without backlash.
- 🔹 The length of the cable is exactly 20 cm (in non-original often 15 or 25 cm).
- 🔹 The package is marked Output: 5V≈1A.
If you're buying a replacement, give preference to proven brands like Baseus or UGREEN that make licensed accessories for Xiaomi. avoid nameless cables with AliExpress - they can damage the power controller of the bracelet.
2. Step-by-step instructions: how to properly charge the bracelet
The charging process of the Mi Band 4 seems intuitive, but many users make mistakes that shorten battery life.
- Remove the capsule from the strap. Press the button on the back of the bracelet and pull the capsule upwards. Don't put too much effort into it. The locking mechanism is fragile!
- Connect the magnetic cable. The contacts at the docking station should fit tightly to the metal pads on the bracelet. Make sure the magnets are pulled in with a characteristic click.
- Connect to the power source. Use it. USB-port of the computer, charger for the smartphone (5V/1-2A) Avoid ports with higher voltages. 5V (For example, in some car charging).
- Wait for the indication. The battery icon with the charging animation will appear on the bracelet screen. If there is no indication, check the contact density or try another one. USB-port.
Full charge time is 1.5-2 hours (0% to 100%) If the bracelet is charged longer than 3 hours, this indicates a battery failure or the use of an unoriginal cable.
☑️ Checklist before charging Mi Band 4
⚠️ Warning: Do not charge the bracelet at lower temperatures +5°C or higher +40°C. This can cause the battery to bloat or the power controller to fail.If the bracelet overheats during charging, turn it off immediately and let it cool for 30 minutes.
3. How long does charging take and how to extend the battery life
The Mi Band 4 battery has a capacity of 135 mAh (in the NFC version - 125 mAh), when properly operated, it can withstand 300-500 charging cycles without significant loss of capacity. However, many users are faced with the fact that the bracelet begins to discharge in a few hours.
| Problem. | Reason. | Decision |
|---|---|---|
| Fast discharge (less than 2 days) | Background processes (synchronization, notifications) | Turn off unnecessary alerts in the Mi Fit app |
| The bracelet does not hold charge after a year of use | Natural wear of the battery | Calibration: Discharge to 0%, then charge to 100% without interruptions |
| Charging is interrupted by 80-90% | Overheating protection worked. | Charge at room temperature, remove the strap |
| The bracelet does not turn on after charging | Deep discharge or damage to the controller | Hold on charging for 30 minutes, then press the reset button (see Section 6) |
To maximize the life of the battery, follow these rules:
- 🔋 Avoid full discharge (charge at 10-20% charge).
- ⚡ Do not leave the bracelet on charging for more than 4 hours - this creates an excessive load.
- 🌡️ Keep the device at temperature +10…+30°C.
- 🔄 Calibrate the battery once every 3 months (full discharge-charge cycle).
💡
If the bracelet has not been used for a long time (more than a month), before charging, let it lie down for 10-15 minutes at room temperature, which will restore the chemical processes in the battery and speed up charging.
4. Frequent charging errors and how to avoid them
Even experienced users sometimes make mistakes that shorten the life of the Mi Band 4, and here are the most common ones and ways to fix them:
Error 1: Using a non-original cable with inappropriate parameters.
Non-original chargers can give current higher 1A, Symptoms: bracelet gets very hot, charging is interrupted by 50-70%, the solution is to purchase a certified cable or use it. USB-hub.
Error 2: Charging from powerful adapters (fast charging).
Quick Charge or Power Delivery adapters (such as those from smartphones) can deliver voltages higher than 5V, which damages the battery. Always use standard 5V/1A or 5V/2A chargers.
Error 3: Trying to charge the bracelet without removing it from the strap.
The contacts on the back of the capsule should be tightly attached to the docking station. If the bracelet remains in the strap, the magnets do not lock properly and charging is interrupted. Always remove the capsule before connecting to the cable.
⚠️ Warning: If the bracelet shows a false charge level after charging (for example, 100% is immediately reset to 20%), this is a sign of a controller failure.
What to do if the bracelet does not respond to charging?
5.How to Clean Contacts and Resolve Charging Problems
Over time, the contacts on the bracelet and docking station become oxidized or contaminated, which leads to a poor connection.
- 🧴 Cotton swabs.
- 💧 Isopropyl alcohol (70% or higher).
- 🔍 Lupa (optional, to inspect small details).
Step-by-step cleaning:
- Soak the cotton swab in alcohol and gently wipe the metal contacts on the back of the bracelet.
- Similarly, clear the contacts at the docking station.
- Allow both devices to dry for 10-15 minutes (alcohol evaporates quickly, but it is better to be safe).
- Check charging – if the problem persists, repeat the procedure or inspect the contacts for mechanical damage.
If the contacts are darkened or covered with green coating (oxidation), use an eraser for careful cleaning. Then wipe again with alcohol. Do not use abrasive materials (sandpaper, metal brushes) - they will damage the coating!
⚠️ Warning: If the bracelet is not charging after cleaning, check the integrity of the spring contacts at the docking station. They must be flat and elastic. If the springs are bent or broken, the charger must be replaced.
6. Resetting and fault diagnosis
If the Mi Band 4 doesn't charge or doesn't work properly, sometimes it helps to reset to factory settings, which will delete all the data from the bracelet, but return it to its original state.
- Open the Mi Fit app on your smartphone.
- Go to Profile → Mi Smart Band 4 → Additional → Resetting.
- Confirm action, the bracelet will reset and return to factory settings.
If the bracelet does not respond to reset via the application, perform a hardware reset:
- Remove the capsule from the strap.
- Connect the bracelet to the charger.
- Press the touch button for 10-15 seconds until the Mi logo appears.
After resetting, try recharging the bracelet. If the problem persists, check the following points:
- 🔌 Cable: Try another USB-port.
- 🔋 Battery: If the bracelet is turned on only on charging and immediately switches off, the battery fails.
- 🛠️ Power Controller: If signs of short circuit (bracelet warms, does not turn on) repair is required.
💡
If after all the manipulations the bracelet is not charged, most likely the problem in the hardware (battery or controller).In this case, contact the service center - self-repair can aggravate the situation.
7. Alternative charging methods (in case of loss of cable)
If the original cablelost is broken and you can’t buy a new one, you can use alternative methods, but remember, these methods do not guarantee safety and can damage the bracelet!
Method 1: Use of a universal docking station.
Some universal smartwatch chargers (such as the Amazfit) have adjustable pins, and you can try to fit them to the Mi Band 4, but the risk of damage to the contacts is high.
Method 2: Directly connect to contacts.
For experienced users: you can carefully solder the wires from USB-cable to the contacts of the bracelet, observing polarity (+ However, this requires soldering skills and knowledge of circuitry!
Method 3: Wireless charging (modified bracelets only).
Some enthusiasts install a wireless charging module in the Mi Band 4, but it requires disassembling the device and loses the warranty. If you are not confident in your abilities, you should buy a new cable.
⚠️ Warning: Alternative charging methods can damage the power controller or even fire the battery. Use them only as a last resort and at your own risk!