Preparation for disassembly: what you need to know before the beginning
Removing the battery with Xiaomi Redmi 4X — It's a challenge that requires not only accuracy, but also understanding the design of the smartphone, and this model, released in 2017, has a non-removable battery soldered to the motherboard via a computer. FPC-Unlike modern adhesive devices, this uses a combination of double-sided tape and mechanical locks, which complicates the process.
Before you start, consider: 90% of damage during dismantling is due to haste or the wrong tools. If you have never disassembled smartphones, it is better to contact the service center - the cost of replacing the battery in Xiaomi is from 1,200 to 2,500 rubles (2026).
Important: Once the battery is removed, the smartphone will automatically reset the time and date settings (due to the power outage of the RTC chip), a normal occurrence not related to a breakdown.
Required tools and materials
For safe removal of the battery you will need:
- 🔧 Plastic mediator (or guitar) - to disconnect the body without scratches.
- 🔨 The screwdriver. PH00 (magnetic) - for the screws of the back cover.
- 🧲 Suction (optional) - helps to lid after heating.
- 🔥 Hair dryer or thermo-air station - for softening the glue (temperature not higher than 60)°C!).
- 🧴 Isopropyl alcohol (90%+) — glue-residue.
- 📦 Logs for screws - so as not to lose small details.
⚠️ Warning: Do not use metal blades or knives, they will damage the plumes or body. Also avoid overheating: if the glue does not lend itself, heat longer at low temperatures, rather than increasing degrees.
Step-by-step: how to disassemble the Redmi 4X and get to the battery
The process consists of 5 stages. Follow them strictly in order:
- Turn off your smartphone and remove it. SIM-Wait for the device to cool down completely if it's in operation.
- Heat the back cover with a hair dryer around the perimeter for 2-3 minutes. Keep the hair dryer at a distance of 5-7 cm, evenly driving along the edges.
- Put the lid on the mediator, starting at the bottom edge (near the Micro-USB connector). If the lid fails, warm up for another 1 minute.
- Take the lid off and put it aside. Be careful, there's a fingerprint scanner plume attached to it.
- Unscrew 10 screws (marked in the photo below) with a cross screwdriver. Rotors of different lengths - remember their location!
When you take the back off, you'll see the battery glued to the body, and it's connected to the motherboard via a JST 1.0 connector (white). Don't pull the battery right away, disconnect the plume first!
Smartphone's off and cooled.|All screws are unscrewed and folded separately|Mediator and alcohol on hand|Photo of the insides taken (for assembly)-->
Battery Disconnection: How Not to Damage the Motherboard
The most critical point is the power plume is disconnected, and an error here can short-circuit or damage the charging controller.
- Take a plastic tweezer or a mediator.
- Carefully apply the white connector to the side (see photo) Pull strictly upwards, not to the sides!
- If the connector does not lend itself, drop 1 drop of alcohol on the base - this will weaken the glue.
- After disconnecting, check the voltage on the battery contacts with a multimeter (should be 0 V).
⚠️ Warning: If you see a spark or hear a crack when you disconnect the connector, stop disassembling immediately! This is a sign of residual voltage in the capacitors. Wait 10 minutes and try again.
| Action. | Risk | How to avoid |
|---|---|---|
| Spinning screws | Throwing off | Use a magnetic screwdriver, do not use force |
| Removal of the back cover | Damage to the fingerprint scanner plume | Put the lid on the opposite side of the plume |
| Battery disconnection | Short circuit. | Check the voltage with a multimeter |
| Battery extraction | Puncture or rupture of the shell | Use a plastic mediator, do not use force |
Removal of the battery: safety and nuances
The battery in the Redmi 4X is glued to double-sided 3M 9448A tape to remove it:
- Tap the edge of the battery with a plastic mediator.
- Slowly drive the mediator along the body, separating the glue, if resistance is strong, drip the alcohol under the battery.
- Don't pull the battery around corners, it can tear the shell. Move evenly around the perimeter.
- Once removed, inspect the battery for swelling, and if the case is deformed, do not put it back in place and store it next to flammable objects.
⚠️ Warning: If the battery starts to make a hissing sound or heats up, this is a sign of the beginning of thermal acceleration. Immediately place it in a non-combustible container (for example, a metal bucket with sand) and take it outside. Do not try to put it out with water!
What to do if the battery is too tight?
Installation of a new battery: compatibility and calibration
For Xiaomi Redmi 4X suitable batteries with the following characteristics:
- 🔋 Capacity: 4100 mAh (original) or 4000-4200 mAh (similars).
- 🔌 Voltage: 3.85 V (nominal).
- 📏 Sizes: 145.5 × 70.5 × 3.5 mm (tolerance) ±0.2 mm).
- 🔗 Connector: JST 1.0 PH-2 (white, 2 contacts).
After installing the new battery:
- Connect the plume to the motherboard.
- Secure the battery with a new double-sided tape (e.g. 3M 9088).
- Put the body back together.
- Charge your smartphone to 100% and calibrate your battery:
1. Charge to 100% and keep on charging for 1 hour.
2. Turn off charging and discharge until automatically turned off.
3. Repeat the cycle 2-3 times.Correct connection of the battery plume (should be clicked when fixing).
- The presence of a short circuit on the board (try the voltage on the contacts of the battery).
- Charging connector state – it may be contaminated or oxidized.-->
Frequent Mistakes and How to Avoid Them
Even experienced craftsmen sometimes make mistakes when working with the Redmi 4X.
- 🔧 Tangled screws: screws of different lengths - if you screw a long one into a place for a short one, you can damage the board.
- 🔌 Damaged print scanner plume: when you remove the cover, it's easy to tear.
- 🔥 Battery overheating: If you heat the dryer for longer than 5 minutes, the glue can dry even more.
- 📱 Misassembly: Forgotten screws or unconnected plumes will result in a broken display or camera.
To minimize the risks, take photos of each stage of disassembly, for example, take a picture of the location of the screws before unscrewing them, which will save hours when assembled.
💡
If the battery is quickly discharged after the battery is replaced, the problem is not with the battery but with the power controller (the BQ25890 chip on the board) and requires a soldering station and experience to replace it.