Users of Xiaomi fitness trackers often face a situation where the device stops responding to touch after a long downtime or complete battery discharge.If your Xiaomi Mi Band 4 does not turn on immediately after connecting to the charger, do not panic. This is a common phenomenon associated with the peculiarities of lithium polymer batteries in deep discharge.
In most cases, the gadget takes time to accumulate the minimum energy level necessary to start the system. However, there are software failures that require a forced reboot. In this article, we will discuss in detail the algorithms of actions that will help to revive the tracker without going to the service center.
It should be understood that the Mi Band 4 is a complex electronic device, and its behavior depends on the state of the firmware and the health of the battery. We will consider both standard on-board methods and ways to emergency restore the system when the system freezes.
Why Mi Band 4 doesn’t respond to charging
The first thing to do is to rule out the trivial reasons for the lack of reaction. Often the problem is not with the tracker itself, but with the way the power is supplied. The contacts on the tracker and the charging cable can become oxidized or contaminated with sweat, which prevents normal current.
If the charging indicator does not light up, try to thoroughly wipe the metal contacts on the capsule and USB-Sometimes it's enough to just move the capsule in the charging slots one millimeter in either direction to restore the connection.
⚠️ Note: If you use a third-party high-current charger (such as from fast charging your smartphone), the power controller may block the power supply for safety purposes. USB-port of computer or adapter with current up to 1 Ampere.
Also, consider the state of the battery itself, because if the tracker was discharged for several months, the chemical processes inside the battery could lead to a deep degradation, in which case the voltage may be below the start threshold of the controller.
For diagnostics, try connecting the device to another power source, and if after 15-20 minutes the screen is still black and the vibration signal is not, there may have been a software failure that requires more in-depth intervention.
Algorithm of inclusion after full discharge
When the battery is discharged to zero, the battery management system (BMS) goes into protective mode. In this state, the Mi Band 4 won't turn on instantly, even if you see the battery icon. It needs time.
Leave the tracker on charge for at least 30-40 minutes without trying to activate it, during which time there is a slow "swinging" of the battery with low currents, only after a certain voltage is reached, the system will allow the main processor and display to start.
What happens inside when you're in deep discharge?
After the device has been charging for a while, try a short tap on the touch button. If the screen catches fire and shows the percentage of charge, the problem is solved. If not, go to the software reboot methods.
It is important not to leave a fully discharged gadget in storage. Lithium polymer batteries are prone to self-discharge, and if the voltage falls below a critical minimum, it will be impossible to restore the capacity.
Forced reset and reset settings
If the battery is charged but the interface is not responding, the operating system has probably been “hang-up” in such cases, where a forced Hard Reset or a reboot through the menu helps.
To perform a soft reboot through the menu (if the screen reacts at all): swipe left to the settings menu, find System and select Reboot. The device will turn off and re-energize in a few seconds.
☑️ Actions when getting stuck
If the menu is not available, you can try the "discharge" method. Leave the tracker without charging until it completely sits down and turns off itself. After that, set it to charge to 100% and try to turn it on again. This often helps to reset the controller errors.
In extreme cases, when a software failure blocks all functions, a complete factory reset may be required, which will delete all training and pairing data, but bring the device back to life.
Diagnostics through the Mi Fit app
The main control and diagnostic tool for Xiaomi Mi Band 4 is the Mi Fit (or Zepp Life) application, which allows you to see the real state of the device, even if the tracker screen itself is turned off.
Open the app on your smartphone and go to the device profile. If the tracker shows as “Connected” but the data is not synced, try clicking the “Disable” button and then search the devices again.
| Status in the annex | Possible cause | Action. |
|---|---|---|
| Not found. | Battery is discharged or Bluetooth is turned off | Charge, check BT |
| Low charge. | Battery requires power | Put it on charge. |
| Synchronization error | Software or memory failure | Reconnect, reset, reset. |
| Update available | There's a new firmware. | Update. |
Also, the tracker profile settings often display the exact percentage of charge, even if the bracelet screen does not show this information, which helps to understand whether the charging process is underway.
If the application offers to update the firmware, be sure to do so. Updates often contain corrections for errors related to power consumption and stability.
Problems with the screen and sensor
Sometimes the device is working, vibrating at notifications, but the screen remains black, which may indicate a malfunction of the AMOLED matrix or the plume, but before sinning on (iron), check the settings.
In the Settings -> Screen menu, make sure that the Wrist Raise feature is activated. If it is turned off, the screen will not light up on its own and will need to be woken by touch.
Try changing the brightness of the backlight. If the screen appears black at minimum brightness, increase the value. Also check if there is a Do Not Disturb or Save Energy mode that can limit the display.
If you put a lot of pressure on certain areas of the screen, if it gets distorted or starts to work, it's a sign of physical damage to the matrix, and then software methods won't help.
When a battery replacement is required
The life of the lithium battery in the Mi Band 4 is an average of 2-3 years of active use. If your device is many years old and it holds a charge for less than a day or does not turn on after charging, most likely, the battery life is exhausted.
Signs of need for replacement:
- 🔋 The device turns off when charged 20-30%.
- 🔋 The tracker is charged instantly (for the 5-10 minutes) and discharges just as quickly.
- 🔋 The capsule is bloated (dangerously!).
- 🔋 The device does not turn on without connecting to USB.
⚠️ Warning: Battery bloating is fire hazard! if you notice the tracker capsule has deformed or the screen has gone "wave", immediately stop charging and dispose of the device.
Replacing the battery in the Mi Band 4 is possible, but requires care, as the capsule is sealed in a sealed case.It is often easier and cheaper to buy a new tracker than risk damaging the electronics on opening.
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Extend battery life: Try not to discharge the tracker to zero regularly. Put it on charge when there is 15-20% left. Deep discharge is the main enemy of lithium batteries.