How to charge Xiaomi Mi Band 4: step-by-step instructions and secrets of long work

The Xiaomi Mi Band 4 fitness bracelet remains one of the most popular activity-tracking gadgets, despite the release of new models, with its main advantages being compact, sensor accuracy and long battery life (up to 20 days with moderate use), but even such a reliable device requires proper handling, especially when it comes to charging. Failure to follow simple rules can lead to rapid battery wear, malfunctions or even breakdown.

In this article, we’ll look at all the ways Mi Band 4 can be charged, from the standard method with the original cable to alternative solutions in case of loss. You’ll learn how long it takes to fully charge, how to avoid typical errors (such as overheating or using uncertified adapters), and what to do if the bracelet does not respond to the power connection.

If you’ve just purchased the Mi Band 4 or experienced charging problems, this guide will help you understand all the nuances, and for experienced users, we’ve prepared expert tips on process optimization and fault diagnosis.

1. Completement and original charger

In the box with Xiaomi Mi Band 4 you will find:

• 📦 The fitness bracelet with the strap itself
• 🔌 Specialized charging cable (with magnetic connector)
• 📄 Short instructions in several languages (including Russian)

The original cable has a unique design: on the one hand, a standard cable. USB Type-A for charging or computer, and magnetic connector that attaches to the back of the bracelet. The Mi Band 4 does not support wireless charging (unlike newer models like the Mi Band 7), so without this cable or its analogue, it is impossible to charge the device.

Many users lose or break the original cable, and you can buy a replacement, but there's a caveat: use only certified accessories. Cheap Chinese counterparts often have the wrong polarity or weak magnet, which leads to:

• ⚡ Slow charging (2-3 times longer than standard time)
• 🔥 Battery overheating
• 🚫 Complete inoperability of the bracelet (in rare cases)

2. Step-by-step instructions: how to charge the Mi Band 4

The charging process takes minimal effort, but there are a few critical moments that are often missed.

1. Take the bracelet capsule out of the silicone strap carefully, pull it toward the screen, and that's what you need to access the charging contacts on the back.
2. Connect the magnetic cable. Match the metal contacts on the bracelet with the cable connector. The magnet must securely lock the connection - if the cable falls off, check the cleanliness of the contacts (see section 5).
3. Connect to the power source. Use it: 🔌 Smartphone charger (5V/1A or 5V/2A) 💻 USB-port 🔋 Power Bank (external battery)

Wait for the start of charging.

The full charge time depends on the current battery level:

It's important! 4 It does not support fast charging (Quick Charge or Quick Charge). VOOC). Use of powerful adapters (9V/2A and above) will not speed up the process, but may cause overheating.

3. Alternative charging methods (if the cable is lost)

Sometimes the original cable gets lost or broken, and there are a few ways out.

Method 1: Universal Magnetic Cable

There are universal charging cables for fitness bracelets on sale (for example, from Baseus or UGREEN). They're good for the Mi Band. 4/5/6 have:

• 🔄 Adjustable polarity (switch) +/-)
• 🧲 Strong magnet for reliable fastening
• 🔌 USB-Type-C or Micro-USB to choose from

The cost of such a cable is from 300 to 800 rubles. the main thing when buying is to check compatibility with Mi Band 4 (check with the seller).

Method 2: Charging from another Xiaomi bracelet

If you have a Mi Band, 5/6, Their cables are partially compatible with version four, but there are risks:

• ⚠️ Incomplete attachment of contacts (may not charge)
• ⚠️ Overheating due to tension mismatch

Method 3: Homemade adapter (for power users)

If you're an electrical engineer, you can weld an adapter from an old Micro-USB cable.

1. Cut off the Micro-USB connector and clear the wires.
2. Salt. + and - to the contacts on the back of the bracelet (check polarity with a multimeter!).
3. Fix the structure with insulation or thermal glue.

⚠️ Attention: This method is risky, because if you make a mistake in polarity, the bracelet can fail!

4.Typical charging errors and their consequences

Even experienced users sometimes make mistakes that shorten the life of the Mi Band 4.

Mistake 1: Using Unoriginal Power Adapters

The bracelet is powered. 5V/0.5–1A. Powerful adapters (for example, from laptop to laptop) 19V) may:

• 🔥 Causing battery overheating
• 📉 Accelerate battery degradation (capacity loss by 30-40% per year)

Error 2: Charging at extreme temperatures

The optimal temperature for charging is from +10°C +35°C. If you charge the bracelet:

• ❄️ In the cold (below 0)°C) - battery may swell
• ☀️ In the sun (above 40)°C: risk of fire (very rare but possible)

Error 3: Keeping 100% charge constant

Lithium batteries (and the Mi Band 4 has a 135mAh Li-Po battery) don't like to run at maximum.

• 📊 Capacity will decrease by 20-25% in 6 months
• 🔋 The time of autonomy will be reduced from 20 to 10-12 days

💡

To extend the battery life, charge the bracelet to 80-90% and do not leave it on charge after reaching 100%.

Error 4: Charging through a damaged cable

If you can see on the cable:

• 🔌 Wrapping or bare wires
• 🧲 Weakened magnet
• 💥 Melt marks.

A damaged cable can short-circuit and disable not only the bracelet, but also the charger.

5. How to Clean Contacts for Reliable Charging

Over time, dust, sweat, or oxide film accumulates on the contacts of the bracelet and cable, which interferes with normal charging, and cleaning should be done every 2-3 months (or more often if the bracelet is actively used during training).

To clean up, you will need:

• 🧴 Cotton swab
• 💧 Alcohol (isopropyl or medical 70%)
• 🧼 Soft toothbrush (optional)

Step-by-step:

1. Wet the cotton swab in alcohol and gently wipe the contacts on the bracelet and cable.
2. For severe contaminants, use a toothbrush (without pressing!).
3. Allow the parts to dry 5-10 minutes before connecting.

⚠️ Attention: Do not use:

• 🚫 Abrasive materials (sandpaper, metal brushes)
• 🚫 Acetone or solvents
• 🚫 Water (can get inside the body)

💡

Regular cleaning of contacts increases the charging speed by 15-20% and prevents malfunctions in the bracelet.

6 Bracelet not charging: causes and solutions

If after connecting to charging on the screen Mi Band 4 does not appear indicator (lightning) ⚡), check the following:

Problem 1: Faulty cable or adapter

Symptoms:

• 🔌 The cable is not fixed by a magnet.
• 💡 The indicator on the bracelet does not light up.

Decision:

• Try another cable or adapter.
• Connect the bracelet to the computer - if charging is going, the problem is in the power supply.

Problem 2: Contaminated contacts

Symptoms:

• ⚡ The charging indicator flashes and disappears
• 📉 The swelling is then turned off (and then turned off)

Solution: Clear the contacts according to the instructions in Section 5.

Problem 3: Software failure

Symptoms:

• 🔄 The bracelet is turned on but does not show the charging process
• 📱 Mi Fit app doesn't see battery level

Decision:

1. Reset the bracelet: Press the touch button for 10-15 seconds until the Mi logo appears.
2. Update the firmware through Mi Fit (Device Profile) → Update of the PO).
3. Reset the bracelet to factory settings (Settings) → Resetting in annex).

Problem 4: Damaged battery

Symptoms:

• 🔋 The bracelet discharges in a few hours.
• 💥 The body swelled or deformed.

Solution: In this case, you need to replace the battery. Contact the Xiaomi service center or a trusted wizard. The cost of replacing is from 800 to 1500 rubles.

7 How to extend the battery life of Mi Band 4

Xiaomi Mi Band 4 is equipped with a lithium polymer battery (Li-Po), which degrades over time, but the right care can increase its life by 30-50%.

Advice 1: Optimal level of charge

The ideal range for lithium batteries is 20-80%. Try not to drain the bracelet to 0% and not to hold it 100% all the time.

• 🔋 Charge at 15-20% charge
• ⏰ Turn off power at 80-85%

Advice 2: Regular use

If the bracelet is idle for more than a month, the battery can lie down.

• 📅 Charge and discharge it up to 50% every 2 weeks
• 🏃‍♂️ Wear at least 2-3 times a week

Advice 3: Energy saving settings

The Mi Band 4 has hidden energy saving features:

• 🌙 Turn off screen lighting for the night: Settings → Raising your hand to activate → Off.
• 📵 Reduce the sync frequency with your phone: Mi Fit → Notifications → Synchronization every 30 minutes.
• 🔍 Turn off unnecessary sensors (such as heartbeat if not used): Settings → Heart monitoring → Including only in training.

Advice 4: Keeping the bracelet

If you have not used the bracelet for a long time:

• 🔋 Charge to 50-60%
• 🌡️ Store in a dry place at a temperature +10…+25°C
• 📦 Remove the capsule from the strap (so that the body does not deform)

8. Frequently Asked Questions (FAQ)