Why Xiaomi Mi 4X Battery Fails and When to Change It
The Xiaomi Mi 4X (also known as the Mi 4i in some regions) was released in 2015, and even with careful use, its original 3120 mAh battery will inevitably degrade by 2026. Typical signs of wear: the phone discharges in 2-3 hours at minimal load, turns off at 20-30% charge or requires a charge connection every 15-20 minutes.
The manufacturer claims a battery life of 500-800 charge cycles, but in practice this figure depends on the operating conditions. Overheating, using non-original chargers, frequent discharges to 0% and storage at 100% charge accelerate wear. If your Mi 4X suddenly began to reboot when connected to charging or heats up more than usual, this is also a reason to check the status of the battery.
Before you start replacing, make sure that the problem is in the battery.
- 🔋 Install the AccuBattery app (available on Google Play) and check the current battery capacity. If it is below 60% of the nominal (less than 1800 mAh), a replacement is required.
- 🔌 Connect your phone to charge and watch for behavior: If the charge jumps (e.g., from 10% to 50% per second), it’s a sign of damage to the battery controller.
- 🔥 Check the physical condition of the battery: if the phone case is swollen or there are gaps between the screen and the back cover, the battery should be changed immediately - the risk of fire is high.
What battery to choose for Xiaomi Mi 4X: original vs analogues
The original battery for the Mi 4X has an MB-J10 and a capacity of 3120 mAh. However, after 2018, Xiaomi officially stopped supplying spare parts for this model, so it is almost impossible to find a new original.
| Type of battery | Capacity | Pluses | Cons | Price (2026) |
|---|---|---|---|---|
| Original b/u (from disassembly) | 3120 mAh | Guaranteed compatibility, stable operation | Limited resource (already partially worn out), risk of buying a marriage | 1500–2500 ₽ |
| Premium analogue (e.g., premium, CAMELION, Remax) | 3200-3500 mAh | New battery, often increased capacity, 6-12 months warranty | Possible problems with charge calibration, not always accurate % indication | 1200–1800 ₽ |
| Budgetary analogue (no-name) | 3000–3100 mAh | Low price, availability | High risk of bloating, short service life, possible problems with the controller | 600–1000 ₽ |
When choosing an analogue, pay attention to:
- 🔍 Protection controller (must be built into the battery, otherwise the risk of short circuit).
- 📏 Thickness: the original battery is 3.85 mm thick. Analogs thicker than 4 mm may not fit into the body.
- 🔌 Compatibility of the connector: Mi 4X 3-pin plume (power, thermistor, data).
⚠️ Warning: Buy batteries only from trusted sellers with warranty. brand fakes CAMELION Baseus or Baseus are often sold with an understated real capacity (for example, instead of 3500 mAh - 2500 mAh.
Tools and preparation for battery replacement
To replace the battery in Xiaomi Mi 4X, you will need:
- 🔧 Screwdriver kit: cross-haired PH00 and flat 1.5 mm (for spinning the screws of the back cover).
- 📱 Plastic blades or mediators (2-3 pieces) for disengaging the body.
- 🔥 Dryer or thermo-air station (to soften the glue under the battery).
- 🧲 Suction (optional, to remove the screen, if required).
- 🛠️ Tweezers and scalpels (for careful detachment of plumes).
- 🔋 New battery with double-sided tape (usually included).
- 📸 Smartphone for shooting the process (it is recommended to take pictures of each step, so as not to confuse the plumes during the assembly).
Turn off the phone and remove it. SIM-map|Work on a clean, illuminated surface|Prepare the container for screws (so as not to lose)|Charge the new battery to 30-50% before installation-->
Before the start of the work:
- Turn off your phone and wait until it is completely cooled (if you have used it).
- Remove the back cover (if it is removable) or prepare a hair dryer to soften the glue.
- Discharge the old battery to 20-30% – this will reduce the risk of short circuit when disconnected.
⚠️ Warning: Do not use metal tools to tamper with the battery, it can puncture the battery body and cause electrolyte leaks. If the battery is swelling, wear safety glasses and gloves: if damaged, it can emit toxic gases.
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If you don’t have a hair dryer, you can use a regular household one, but keep it 10-15 cm away from your phone so as not to melt the plastic of the case.
Step-by-step: how to disassemble Xiaomi Mi 4X and remove the old battery
Disassembly of the Mi 4X requires care - the body of the phone is glued together and the plumes are fragile.
Step 1: Removing the back cover
1. Heat the back of the phone (especially at the edges) with a hair dryer for 2-3 minutes. Temperatures should be 60-80°C - enough to soften the glue, but not melt the plastic.
2. Insert a plastic blade into the gap between the body and the screen (start at the bottom edge where the charging connector is located). Carefully drive the blade along the edge, separating the lid.
3. After the cover is removed, put it aside. Be careful: it has a fingerprint scanner plume attached to it (if you have one in your model).
Step 2: Disconnecting the plumes
1 Unscrew 8 screws that fix the metal plate above the battery (use the PH00 cross screwdriver).
2. Gently tweez the plate and take it off. Underneath it you will see:
- 🔌 Battery plume (3 contacts).
- 📶 Antenna connectors (do not touch them without needing to).
- 🖥️ Display plume (covered with black tape).
3. Unplug the battery plume with a scalpel or a plastic spatula.
Step 3: Remove the old battery
1. Warm the battery with a hair dryer (50–60°C) for 1-2 minutes. This will soften the glue.
2. Pull the tongue carefully (if any) or slap the battery with a plastic spatula on the side. Do not use metal tools!
3 If the battery doesn't respond, reheat it and try again. Don't put too much effort into it, you risk damaging the motherboard.
4 After removal, examine the battery: if it is swelled, do not puncture it - dispose of it according to the rules for handling hazardous waste.
What to do if the battery is too tight?
Installation of a new battery and assembly of the phone
Before installing the new battery:
- Clean the place under the battery from glue residues (use alcohol and cotton swab).
- Check the integrity of the contacts on the motherboard – they should be clean and not bent.
- Remove the protective film from the new battery (if any) and glue the double-sided tape from the kit.
Installation:
- Connect the new battery plume to the circuit board connector, make sure it sits before the click.
- Carefully put the battery in place, starting at the bottom edge, press it to securely lock.
- Install the metal plate back and twist all 8 screws (don't pull over!).
- Connect the fingerprint scanner plume (if it has been disconnected) and snap the back cover.
⚠️ Warning: After you change the battery, the phone may not turn on right away. This is normal: first connect it to charging for 10-15 minutes, then try to turn it on. If the screen is not responding, check the connection of the display plume.
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After assembly, be sure to check all the functions: cameras, speakers, sensors and wireless modules. If something doesn't work, chances are you forgot to plug the plume in or damaged it during disassembly.
Calibration of the new battery: why it matters
The new battery requires calibration so that the charge controller can correctly determine its capacity, without which the charge indicator can show incorrect values (for example, 100% at a real 80%).
Calibration process:
- Full discharge: Use your phone before you turn off automatically (do not plug in charging even if a low charge warning appears).
- Charging to 100%: plug in the original charger and wait for full charge.
- Stabilization: After reaching 100%, leave your phone charging for another 1-2 hours.
- Recycle: Recharge the phone to 0% and charge it to 100% again. Repeat 2-3 times.
You can use the Battery Calibration app (available on Google Play) to speed up the process, but manual calibration is more reliable.
- ⚡ The phone’s operating time will increase by 20-30%.
- 📊 The charge indicator will show the exact values.
- 🔄 Reduced risk of sudden shutdowns.
If after calibration the phone still discharges quickly, check:
- 🔌 The quality of the new battery (possibly defective).
- 📱 Background processes (use Settings) → Battery → Using a battery for analysis).
- 🔥 Overheating (set up) CPU Monitor to track processor temperature).
Frequent Mistakes and How to Avoid Them
Even with a careful battery replacement, users often face problems, and here are the most common mistakes and solutions:
| Problem. | Reason. | Decision |
|---|---|---|
| The phone will not turn on after assembly. | Unconnected battery plume or display | Take the phone apart and check all the connectors. Make sure the battery plume is plugged in before the click. |
| Battery discharges quickly (less than 4 hours) | Poor analogue or lack of calibration | Check the battery with a tester (should be 3.7-4.2V). If the voltage is lower, replace the battery. Calibrate. |
| The phone overheats when charging | Charge controller damaged or non-original RAM used | Use a 5V/2A charger. If the heat is maintained, check the charge at the service center. |
| Charge indicator "jumps" (for example, from 50% to 20%) | Poor battery plume contact or faulty controller | If the problem persists, the power controller needs to be replaced. |
If after replacing the battery, the phone began to spontaneously restart, this may indicate:
- 🔌 Poor battery contact (check the plume fixation).
- 📱 Damage to the motherboard (for example, in the careless removal of an old battery).
- 🔥 Overheating of the processor (clean the phone of dust, replace the heat paste).
⚠️ Warning: If the battery is not charged for more than 1-2 hours after the battery is replaced, do not rush to blame the battery. First check the current consumption in standby mode (should be no more than 50-100 mA). High current indicates a software problem (viruses, background processes) or hardware malfunction (for example, a damaged communication module).