Are you in a situation where the Xiaomi Mi Band 4 has been discharged to zero, and the original charging cable is lost, broke or simply unavailable? Don't panic - there are several ways to bring the bracelet back to life without a branded accessory. In this article, we will discuss 7 working charging methods, including the use of improvised means, adapters from other devices and even homemade solutions.
It's important to understand that the Mi Band 4 has a unique charging connector, the magnetic contacts on the back of the case, which are both plus (reliable mount) and minus (complicity with other cables), but with some tricks you can get around this limitation, we will also tell you which methods are safe and which can damage the device, and give recommendations for extending the battery life.
If you're willing to experiment, you'll do it. But remember, you do all the power manipulations at your own risk. If you do the wrong thing, you have a chance to knock the bracelet out of order or reduce battery capacity, so follow the instructions carefully and don't ignore the warnings.
1.Use of charging from other versions of the Mi Band
The easiest and safest way to do this is to use the cable from other Mi Band models, but not all chargers will work.
- ✅ Mi Band 3/5/6 — All the connectors are identical, the voltage and the current are the same, and you can charge them without worry.
- ⚠️ Mi Band 2 is partial compatibility. Contacts are different, but with a neat connection (with tape fixing) it can work.
- ❌ Mi Band 1/1S — The connector is fundamentally different, trying to connect is useless.
- 🔄 Mi Band 7 and later backwards compatibility, and their cables will fit the Mi Band 4, but not vice versa.
If you have a charger from the Mi Band 5 or 6, just plug it into the bracelet, it should start charging automatically, as long as the contacts fit tightly, if the cable is hanging, lock it with tape or rubber band, but do not squeeze the case.
⚠️ Warning: Do not use Amazfit or other brands chargers, even if they look similar. The voltage may vary, leading to overheating of the battery or failure of the power controller.
2. Charging through USB-port with a homemade adapter
If there is no cable at hand, there is USB-A port (from a computer, power bank or phone charger) can be built to build a temporary adapter:
- 📌 Two thin wires (for example, from unnecessary headphones or USB-cable).
- 🧲 Small magnet (can be removed from old electronics or toys).
- 🔌 USB-The sluice (or any power source with an exit) 5V).
- 🛠️ Fixing insulation or heat-glue.
Step-by-step:
- Cut off from USB-cable connector (if you use a whole cable, just expose the wires (+5V) black (GND) wire.
- Seal them or tightly twist them with thin wires (length ~ 5 cm).
- Stick the magnet to the back of the bracelet so that it attracts contacts (as in the original cable).
- Attach the wires to the contacts of the bracelet: red - to the plus (usually marked as "+"), black - to the minus.
- Set the design with a seal and connect to USB-port.
If done correctly, the charge indicator will appear on the bracelet screen. Don't leave the device unattended - homemade adapters can overheat.
Polarity of wires (plus to plus, minus to minus)|
Strength of magnet attachment |
No short circuit |
Power supply voltage (5V only)|
Disconnection at the first signs of overheating-->
3. Alternative power sources: power bank, phone, laptop
If you have an external battery, an OTG smartphone or a laptop, you can try charging the bracelet through them, and the main thing is to ensure that the contacts are connected correctly.
| power supply | Required accessories | Pluses | Cons |
|---|---|---|---|
| Power bank | Homemade adapter or cable from Mi Band 3/5 | Autonomy, high capacity | Risk of overheating when connecting incorrectly |
| Smartphone (OTG) | OTG-cable + homemade adapter | Always at hand, you can charge on the road | Slow charging, phone discharge |
| Laptop/PC | USB-bare-wire | Stable voltage, process control | You need to disassemble the cable, the risk of damage to the port |
You will need to connect to a smartphone OTG-adapter (adapter with microUSB/Type-C on USB-A). Next, act like a power bank: connect a homemade adapter or native cable from another Mi Band model. OTG-Charging – Check This In Advance.
⚠️ Warning: When charging from a laptop or PC, turn off the fast charging mode (if any). High current can damage the bracelet power controller. Optimal current for the Mi Band 4 is 100-200 mA.
4 Wireless charging: myth or reality?
Many users are wondering if you can charge the Xiaomi Mi Band 4 wirelessly, like a smartphone induction pad, and unfortunately, this model does not have a wireless charging module, so this method will not work.
However, there is a workaround: use a wireless receiver with USB-For example, some power banks support wireless charging for phones and have USB-port for other devices:
- Put the power bank on wireless charging.
- Put him on. USB-Port of a homemade adapter for Mi Band 4.
- Charge the USB-exit bracelet.
It's not really wireless charging in the literal sense, but it's not wired from the outlet, and the main downside is the double loss of power (first on wireless transmission, then on conversion to USB), so it's going to be very slow.
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If you often have to charge the bracelet in camping conditions, buy a compact power bank with a solar panel in advance. It will allow you to charge the Mi Band 4 even without access to the power grid using a homemade adapter.
5. Emergency methods: batteries, power supplies, car lighter
In critical situations, when there is no USB-In the port, alternative DC sources can be used:
- 🔋 Batteries. AA/AAA — I'll use a couple of finger batteries (3V) with a homemade holder. 9V Batteries ("Crona") - too high voltage!
- 🚗 Car lighter - through the adapter to USB (12V → 5V). It is important to check the adapter output voltage.
- 💻 Power supply from the router - most give 5V/1A, But you need to bare the wires and connect them to the contacts of the bracelet.
When using batteries, observe polarity and do not exceed the voltage of 5V. To stabilize, you can use a diode 1N4007 (it will reduce the voltage by about 0.7V).
[Battery 3V] — [Diod] — ► [Plus contact Mi Band 4]
[Battery 3V] — — — — — — — — ► [Minus contact Mi Band 4]This method is suitable only for extreme cases - the constant use of unstable power sources reduces the battery life.
What happens if you confuse polarity?
6. How to extend the life of the battery after non-standard charging
If you have managed to charge the bracelet in an alternative way, monitor its condition in the following days.
- ⚡ Reduce battery capacity due to unstable current or voltage.
- 🔥 Disable the power controller – if there was a voltage surge.
- 📉 Reduce the time of autonomy due to the violation of chemical processes in the battery.
To minimize damage, follow these tips:
- 🔄 Full discharge-charging cycle – after non-standard charging, discharge the bracelet to 0% and charge up to 100% with the original cable (if any.
- 🛡️ Avoid overheating – do not leave the bracelet in the sun or near heat sources after charging.
- ⏱️ Reduce charging time – don’t keep the bracelet on charge for more than 2 hours, even if the indicator doesn’t show 100%.
If after alternative charging the bracelet began to discharge quickly or incorrectly display the percentage of charge, try to reset it to factory settings through the Mi Fit application:
- Open Mi Fit. → Choose your bracelet.
- Go to Settings → Additional → Reset.
- Confirm the reset and wait for the reset.
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After charging the Mi Band 4, it may take 2-3 full charge-discharge cycles to restore the battery to normal operation. If problems persist, the battery or controller is likely damaged.
7.Where to buy the original charging and how to avoid fakes
If alternative methods do not suit you, the best way is to purchase an original charger, which is inexpensive (from 300 to 600 rubles), but guarantees the safety and long life of the bracelet.
- 🛒 Xiaomi’s official store – mi.com or brand stores (e.g. Mi Store).
- 🌍 AliExpress – look for sellers with a rating above 98% and reviews about the originality of the product.
- 🏬 Electronics stores - Svyaznoy, M. Video, Eldorado (check the package for the presence of a hologram).
How to distinguish the original from the fake:
| Sign. | Original | Fake. |
|---|---|---|
| Packaging | White cardboard with Xiaomi logo, hologram | Thin plastic, blurred text, no hologram |
| Cable | Soft silicone, clear markings. | Hard plastic, smell of chemistry, typos in the text |
| magnet | Gravity of attraction moderate, precise landing | Too weak or strong magnet, backlash |
| Price. | 300 to 600 rubles | Below 250 rubles (often a "Chinese copy") |
Remember, cheap fakes can not only hold the bracelet poorly on charge, but also damage the battery due to unstable voltage.