Xiaomi Mi Band 4
The problem can be both a simple contamination of contacts and a serious breakdown of the power controller. In this article, we will examine all possible reasons why the Mi Band 4 does not charge, from software failures to hardware malfunctions. You will learn how to diagnose the problem yourself, what to do first, and when to contact the service center.
For convenience, we have a table of symptoms and solutions, and a checklist for quick check-up, so if you're in a hurry, go straight to Emergency Responses: What to do in 5 minutes.
Emergency measures: what to do in 5 minutes
Before you disassemble the bracelet or carry it for repair, follow these simple steps. In 60% of cases, the problem is solved in just a few minutes:
1. Reset the bracelet. Press the touch button for 10-15 seconds until the Mi logo appears. If the bracelet is completely discharged, first connect it to charging for 10-20 minutes, then try rebooting.
2. Clean the contacts. Take a cotton swab dipped in alcohol and gently wipe the gold contacts on the back of the bracelet and the metal springs on the charger. Don't use abrasive materials - they will damage the coating.
3. Check the cable and the adapter. Connect the charger to the other one. USB-port or adapter (preferably original from Xiaomi with output) 5V/1A). If you use a power bank, try charging from the socket.
4. Reset settings. In the bracelet menu, find Settings. → Reset → Attention: this will delete all local data (steps, pulse), but often helps with software failures.
☑️ Quick diagnostics of Mi Band 4
Top.-7 Reasons Why Mi Band is a Mi Band 4 chargeless
If emergency measures did not help, we will analyze every possible cause in detail - from the most common to rare hardware breakdowns.
1. Contamination or oxidation of contacts
Over time, the gold contacts of the bracelet and the charging springs accumulate sweat, dust, residues of cream or soap, which disrupts the tight contact and prevents the passage of current.
- 🔴 The charging indicator flashes and goes out
- 🔴 The bracelet is charged only in a certain position.
- 🔴 The swelling is going to stop (it will stop)
2. Faulty cable or adapter
The original Xiaomi chargers are designed for currents of 300-500 mA. If you use uncertified cables or adapters with output. >1A, The power controller of the bracelet may block charging, and the problem may be a cliff inside the cable (often broken at the base).
3. Failure of firmware or software
After upgrading to 1.0.9.54 or 1.0.9.66, some users encounter a bug where the bracelet "does not see" charging, although the contacts are clean.
- 📱 The bracelet is switched on but not charged
- 📱 Mi Fit App Shows 0% Charge Despite Connecting to Charge
- 📱 After resetting the settings, the problem temporarily disappears
4. Bloated or worn-out battery
The lithium-polymer batteries in the Mi Band 4 are designed to last 300 to 500 charge cycles. After 2-3 years of heavy use, the capacity drops by 30 to 50 percent, and the bracelet may suddenly turn off or not hold a charge.
- 🔋 The bracelet discharges in a few hours.
- 🔋 The body slightly swelled (seen by the gap between the glass and plastic)
- 🔋 Charging is very slow or stops at 20-30%
5. Failure of the power controller
The chip that controls the charging may fail due to voltage surges, short circuits, or factory defects.
- ⚡ The bracelet does not respond to charging at all (no indication)
- ⚡ When connecting to USB The computer gives an error "Device not recognized"
- ⚡ The bracelet warms up when trying to charge
Mechanical damage
Strikes, falls or severe compression can damage:
- 🛠️ Bracelet fees (cracks on the tracks)
- 🛠️ Charging contacts (bending springs)
- 🛠️ A plume connecting the battery to the board
7.Problems with the Mi Fit app
Rarely, an application crash blocks the charging process, such as when the settings are power-saving or the bracelet is getting stuck on data synchronization.
How do you check if the PO is to blame?
Table: Symptoms and solutions
| Symptoms. | Probable cause | Decision |
|---|---|---|
| The indicator flashes and goes out. | Dirty contacts or poor connection | Clean contacts with alcohol, press the bracelet to charging |
| Bracelet is not turned on, charging is not going | Discharged to zero or firmware failure | Hold on charging 30.+ minutes, then reset |
| Charging is very slow (1% per hour) | Faulty cable or bloated battery | Try another cable, check for body bloating |
| The bracelet warms up when charging | Short circuit or failure of the controller | Shut it down immediately! |
| Charging is only up to 80-90% | Failure of battery calibration | Fully discharge, then charge to 100% without interruptions |
Next Next post: How to Fix the Mi Band 4 Charging
If you're ready to go into repairs, follow this instruction, warning: disassembling the bracelet is not warranty (if it's still in effect).
Step 1 - Disassemble the bracelet
You'll need:
- 🔧 Plastic blade or mediator
- 🔧 Tweezers
- 🔧 Fryer (for softening glue)
1. Heat the hair dryer edge of the glass bracelet (30-40 seconds) - this will soften the glue.
2 Carefully tuck the glass with a plastic blade on either side. Move around until the glass is gone.
3. disconnect the battery plume from the board (it is attached with a small connector).
💡
If you can't unplug the plume, don't pull it by force -- you better heat the board with a hairdryer again, and too much effort can tear the contacts off.
Step 2. Battery check
1. Examine the battery for bloating. If it is deformed, it needs to be replaced.
2. Check the voltage with the multimeter:
- Normal: 3.7–4.2V
- Critically low: <3.0V (need to charge with an external device)
- Short circuit: 0V
Step 3. Cleaning the board
Use a brush soaked in isopropyl alcohol to clear the board of dust and oxides.
- 🔍 Charging contacts
- 🔍 Controller chip (usually marked as BQ25101 or similar)
- 🔍 The paths around the battery
Step 4: Replace the battery (if necessary)
For Mi Band 4, a type battery is suitable 3.8V 130mAh plug-in JST 1.0. When soldering, observe polarity:
- 🔴 Red wire — "+"
- ⚫ Black wire — "-"
Step 5: Assembly and testing
1. Connect the battery plume back to the board.
2. Set the glass in place and press (glue is not required - the body is held by pressure).
3. Connect to charging. If the bracelet doesn't turn on, try pressing the button for 10 seconds.
💡
If the bracelet doesn't charge after disassembly, the problem is probably the power controller, and replacing it requires soldering and trusting the professionals better.
Frequent Repair Mistakes and How to Avoid Them
Many users make the problem worse by trying to fix the bracelet incorrectly.
⚠️ Warning: Never use acetone, gasoline or other aggressive solvents to clean your contacts! They destroy the protective coating and can cause corrosion.
Error 1: Charging from Power Bank or Uncertified Adapters
The bracelet is sensitive to power quality, and cheap power bank or unstable voltage adapters can take out the charging controller.
Mistake 2: Strong pressure on the bracelet when charging
This can bend the contacts inside the charger or damage the springs.
Error 3: Using metal objects to clean contacts
Needles, knives or screwdrivers scratch the gold coating, impairing conductivity.
Error 4: Disassembly without battery shutdown
Short circuits when working with the board can burn the chips.
⚠️ Warning: If the bracelet stops turning on after disassembly, check if the display plume has broken off.
When to contact the service center
Not all breakdowns can be repaired by yourself.
- 🛠️ The bracelet does not respond to charging and rebooting
- 🛠️ On the board you can see burnt elements or cracks
- 🛠️ The battery is swelling or leaking
- 🛠️ After disassembly, new problems appeared (screen does not work, does not synchronize)
The cost of repair in official Xiaomi services:
- 💰 Replacement of the battery: 800-1200 rubles.
- 💰 Repair of the power controller: 1500-2000 rubles.
- 💰 Diagnosis: 300-500 rubles.
If the bracelet is older 2 Sometimes it’s cheaper to buy a new Mi Band. 6/7, It's better than repairing the old one, but for the Mi Band. 4 Parts are still sold, so the recovery is often justified.