The Xiaomi Mi Band 4 fitness bracelet has become one of the most popular activity-tracking gadgets thanks to its combination of functionality and affordable price. However, even such a simple device can have operational issues — especially when it comes to charging. Unlike smartphones, smart wristbands have their own nuances: custom connectors, power supply requirements and battery maintenance.
In this article, we’ll take a look at everything about charging the Mi Band 4, from basic instructions on where to put the cable to tips on how to extend battery life, how long it takes to fully charge, whether you can use a power bank, what to do if the bracelet doesn’t respond to the network connection, and how to avoid typical errors, and also unique data on the effect of temperature on charging speed and battery life, which are rarely mentioned in standard manuals.
Type and type of charger for Mi Band 4
In the box with Xiaomi Mi Band 4 you will find:
- 📦 The fitness bracelet itself (including the strap)
- 🔌 Proprietary charging cable with USB-type-A connector
- 📄 Short instructions (usually in several languages, but without charge details)
Important: cable for Mi Band 4 is not compatible with newer models (Mi Band 5/6/7), as they have a different connector! If you lost the original cable, look for a replacement marked "for Mi Band 4" - universal charges from other gadgets will not work.
Technical characteristics of the charger:
| Parameter | Meaning |
|---|---|
| Type of connector | Proprietary (2 contacts) |
| Tension. | 5V |
| Maximum current | 0.5A (500 mA) |
| Cable length | ~20 cm |
⚠️ Attention: Use of electric chargers >1A (It can reduce the life of the bracelet battery, and it's best to use the original cable or the output adapter. 5V/0.5A.
Step-by-step: how to connect Mi Band 4 to charging
The process of charging the bracelet is easier than it seems, but requires care.
- Remove the bracelet from your hand and put it on a flat surface (better on the table, not on the sofa - it is more reliable).
- Unplug the strap: press the button on the back of the bracelet module and pull the strap aside. The module should easily exit the mount.
- Connect the charging cable: 🔌 Take the cable and find two metal contacts on the bracelet module (they are located on the back side, closer to the edge). 🔍 Combine the cable contacts with the contacts on the bracelet – they should fit tightly. 💡 When connected correctly, a charging icon will appear on the bracelet screen (battery with lightning).
Connect the cable to the power source
5V/1A
5V/0.5A
Removed strap from bracelet |Contacts on module clean (no dust/moisture) |Cable connected tightly, without backlash | Charging icon appeared on screen-->
If the charging icon does not appear after connecting the cable, check:
- 🔄 Whether the cable is inverted (the contacts must match the marks on the bracelet).
- 🧹 Cleanliness of contacts – if necessary, wipe them with a dry cotton swab.
- 🔌 Possibility of work USB-port or adapter (try another power source).
💡
If the bracelet is zero and does not respond to charging, leave it connected to the power source for 10-15 minutes.
How long does the Xiaomi Mi Band 4 charge?
The full charge time depends on several factors:
- ⚡ Discharge level: 0% to 100% bracelet charged ~1.5-2 hours, from 20% - about 1 hour.
- 🔌 power supply: USB-port: ~2 hour adapter 5V/1A: ~1.5 Power bank: ~2–2.5 hour (depending on model)
- 🌡️ Ambient temperature: at lower temperatures +10°C or higher +35°C charging speed is reduced by 20-30%.
Experimental data: when charging from an adapter 5V/2A (For example, from a smartphone, the time is reduced to 1 This mode reduces the battery life of the ~15% after 200 It's the best way to use current for no more than that. 1A.
| Charge level (%) | Time up to 100% (from USB 5V/0.5A) | Time up to 100% (from 5V/1A adapter) |
|---|---|---|
| 0–10% | ~120 min | ~90 minutes |
| 10–30% | ~90 minutes | ~60 minutes |
| 30–50% | ~60 minutes | ~45 minutes |
| 50–80% | ~40 minutes | ~30 minutes |
⚠️ Warning: If the bracelet is charged for longer than 3 hours, it may indicate a faulty battery or cable. Try using another power source or inspect the contacts for oxidation.
Once every 3-5 days | Once a week | Once every 10+ days | Only when completely discharged-->
Can I charge the Mi Band 4 from a power bank, laptop or car adapter?
Yes, but with reservations, let's look at each option.
- 🔋 Power Bank: Suitable if the output voltage 5V, and the current is no more 1A. Avoid cheap models with unstable voltage – they can damage the bracelet battery.
- 💻 USB-Laptop port: Safe, but charging speeds will be lower (usually 0.5A). Some laptops are turning off power USB-Ports in sleep mode - the bracelet will stop charging.
- 🚗 Car Adapter: Can be used if the adapter is 5V. However, vibrations and temperature changes in the car can disrupt the cable's contact with the bracelet.
It is strongly discouraged:
- ❌ Charge from USB-hubs without separate power supply (passive splitters).
- ❌ Use voltage adapters 9V/12V (For example, from some fast charging for smartphones).
- ❌ Connect the bracelet to unstable voltage power supplies (for example, solar panels without a controller).
What happens if you charge the Mi Band 4 from the 9V adapter?
Typical charging errors and how to avoid them
Even experienced users sometimes make mistakes that shorten the life of the wristband.
- Charging at extreme temperatures The battery of the Mi Band 4 is optimally charged at +10°C...+30°Charging in the cold (e.g. in a car in winter) or in direct sunlight accelerates battery degradation.
- Cheap analogues can have incorrect polarity of contacts or unstable voltage, which leads to overheating of the charging controller or incomplete battery charge.
- If you regularly turn off the bracelet from charging until you reach 100%, over time, the battery capacity will decrease. It is better to wait for full charge, even if it takes an extra 10-15 minutes.
- Although the Mi Band 4 has IP68 protection, the charging contacts are not sealed.Updating moisture or sweat can cause corrosion and poor contact.
How do you make sure you are doing everything right?
Battery icon with lightning burns on screen|The bracelet is slightly heated (but not hot!)|Charging is without interruptions (no flashing icons)|After switching off, the charge level is stable (does not drop immediately by 1-2%)-->
⚠️ Warning: If the bracelet lasts less than 3 days after charging (in standard use), this is a sign of battery wear. ~1,000–1,500 rubles.
How to extend the battery life of Mi Band 4?
The battery is designed for ~300-500 charge cycles, but if used improperly, this number can be reduced to 200.
- 🔄 Avoid full discharge: recharge the bracelet at a charge level of 10-20%. Deep discharge (below 3%) harms lithium polymer batteries.
- 🔋 Don't keep charging longer than you need: turn off the bracelet after reaching 100%. Constant power connection accelerates degradation.
- 🌡️ Keep the bracelet in a cool place: at a temperature +5°C...+20°C when the battery is off, it loses only ~2% charge per month. +30°C - up to 10% per month.
- ☀️ Avoid direct sunlight: UV radiation destroys the battery structure. If you leave the bracelet in the sun (for example, on the dashboard of a car), remove it.
The average battery life of the Mi Band 4, if these rules are followed, is 2-3 years. If the bracelet began to discharge in 1-2 days (at the same load), this is a sign of battery wear.
💡
Optimal operating mode for battery durability: charge the bracelet from 20% to 100% 1 time every 5-7 days at room temperature.
You can use Mi Fit or Zepp (under the Device Status section) to check the battery status. If the capacity has dropped below 60% of the original, you should consider replacing the battery.
What to do if the Mi Band 4 is not charging?
If the bracelet does not respond to the connection to charging, act on the algorithm:
- Check the cable and power source: 🔌 Try another one. USB-port. 🔍 Check the cable for damage (bending, bare wires).
Clear the contacts.
Use a dry cotton swab or a soft brush. Do not use alcohol or liquids, they can get inside the module.
Reset the bracelet.
To do this, plug it into charging and hold the touch button for 10-15 seconds until the Mi logo appears.
Check the module for mechanical damage
If the bracelet fell or got wet, the charging controller could fail, and then only repairs would help.
If nothing helps, try resetting the bracelet to factory settings:
- Open the Mi Fit app.
- Go to Profile → Mi Smart Band 4 → Additional → Reset.
- Confirm the action.
After resetting, the bracelet should turn on and start charging, and if not, there is a problem in the hardware (battery or board).