Xiaomi's current Redmi series smartphones are famous for their autonomy, but even the most capacious batteries lose their original capacity over time. If your device starts to run out in a couple of hours, spontaneously shut down in the cold, or swells up while lifting the back cover, then it's time to think about repairing it. Replacing the power supply is a procedure that you can do yourself with a minimum set of tools and basic accuracy skills.
In this article, we will discuss the process of battery replacement, paying special attention to the nuances of disassembly of different models. It is important to understand that lithium polymer batteries are sensitive to mechanical damage and overheating, so rush is unacceptable.
Before you start physical intervention, you need to make sure the diagnosis is accurate. Sometimes charging problems are not due to wear and tear of the chemistry, but to software failures or malfunction of the power controller on the board. However, if the phone is more than two years old and it has been actively used, the degradation of the battery is the most likely cause of instability.
Diagnosis of battery status
The first step is visual inspection and software testing, and bloating is the most obvious sign that you can't ignore, because if the phone stopped lying flat on the table and started spinning like a yula, or the back panel moved away from the frame, it's a signal of a buildup of gas inside the sealed shell.
For deeper analysis, you can use the built-in MIUI diagnostics. Security often has a Verification section that scans the main nodes of the system, and there are third-party utilities that read data from the controller.
- 🔋 A sharp drop in charge: the phone shows 20% and suddenly turns off.
- 📉 Long charging: the process of replenishing energy takes much longer than before.
- 🌡️ Heat: the body warms up significantly even with simple tasks, such as calling or viewing messages.
- 💥 Bloating: Physical change in the geometry of the body or detachment of the screen / cover.
⚠️ Warning: If you notice a severe bloating, do not attempt to pierce the battery or force it into place.
Software methods show only indirect signs: accurate inference about the state of the resource of charge-discharge cycles can be made only after opening and measuring the voltage under load, but for the home user the symptoms described above are usually enough to make a decision about buying a new part.
Tools and training required
You can't replace a smartphone with the right tools, and you can't open a smartphone with a knife or a screwdriver with a wide sting, and you can often end up with cracks in the glass or damage to the internal plumes, and you'll need a specialty kit to work with Redmi.
The main tool will be a suction cup and mediators (plastic blades), metal objects are strictly prohibited, as they can close contacts on the motherboard or break through the insulation, which will lead to a short circuit.
☑️ Battery replacement kit
You will also need a screwdriver like Torx T5 or Phillips #00, as the screws in Xiaomi often have a star-shaped or cross hat.
Heating elements, such as a hair dryer or a special heating pad, are necessary to soften the glue that holds the back cover. Without heating, the glass can crack when you try to detach. The optimal heating temperature is about 80-90 degrees Celsius, you need to heat evenly around the perimeter.
Choosing a quality replacement
The component market is full of offers, but finding a really high-quality battery is difficult. Xiaomi's original batteries have special safety tags and QR-And the codes that you can check on the manufacturer's official website, unfortunately, there are a lot of fakes.
When choosing, consider the capacity specified in mAh (milliamper-hours), which must meet the factory specifications of your model, low capacity will lead to rapid discharge, and overstated (which is often written on cheap copies) is physically impossible in the same dimensions.
| Parameter | Original | Quality copy | Cheap forgery |
|---|---|---|---|
| Capacity | Conforms to the stated | Close to the stated (85-90%) | Significantly lower (50-60%) |
| Weight. | Standard. | It's a little easier. | Noticeably lighter (less chemistry) |
| Controller | Protected against overloads | Basic protection | Absent or of poor quality |
| Resource | 500+ cycles | 300-400 cycles | 100-150 cycles |
Avoid buying batteries without packaging or with a blurred label. A good battery should have a clear label, production date and serial number. Often, high-quality analogues from well-known brands (for example, Nohon or Deji) have protective holograms.
How to check the battery after purchase?
Body disassembly process
Disassembly of modern Redmi models begins with the device being turned off. This is critical for safety and preventing short circuits. SIM-cards to provide air output during heating and not damage the mechanism.
Heat the back cover around the perimeter. Keep the hair dryer at a distance of 3-5 cm, constantly moving it so as not to overheat one point. The glass should become warm but not burning hot. After 2-3 minutes of heating, gently insert the suction cup into the bottom of the cover and pull, creating a gap.
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Instead of a hair dryer, you can use a hot water medical heating pad, putting your phone down on it with a screen for 5-7 minutes, which is a more gentle method, eliminating the risk of overheating the matrix.
Insert a thin plastic mediator into the gap, drive along the edges, cutting the adhesive layer, and don't dip the mediator deep so you don't hit the plumes coming from the buttons or the fingerprint scanner if it's embedded in the switch button.
- 🛠️ Carefully disconnect the fingerprint scanner plume (if any).
- 🔩 Unscrew all visible screws that fix the protective plate.
- 📱 Remove the plastic lining covering the display and battery plumes.
- 🔌 Disconnect the main battery plume from the motherboard.
Once the plume is turned off, you can move on to removing the battery itself. In most Xiaomi models, it's glued to the frame with double-sided tape. You can't pull the plume, it breaks easily.
Removing the old battery and installing a new battery
To extract the old battery, it is best to use special hoods with suction cups or a thin plastic card, placing it under the battery, and if there is no suction cup, you can gently tamper with the edge of the battery with a spatula, trying not to damage the shell.
⚠️ Warning: It is strictly forbidden to use metal tools to smack the battery.Puncture of a lithium polymer battery will cause instant fire and the release of caustic smoke.
Clean the seat of the old glue. The surface must be clean and fat-free so that the new battery is flat and secure. The new part is often already covered with a film-protected adhesive layer.
Install the new battery by pairing the connector with the circuit board. Don't force the plume in, it should stand up easily. Once connected, be sure to check the phone's response: the screen should catch fire and the device should start charging.
If the phone is on and shows the correct percentage of charge, you can proceed to the final assembly, make sure that all the plumes are tightly pressed by connectors and closed with metal plates.
Assembly and primary calibration
The assembly is done in reverse order. Stick the new battery, install protective plates and twist the screws. The back cover before installation is also recommended to warm up and apply a new layer of glue or special B-7000 tape for leakproofness.
Once the phone is turned on, it is recommended to perform a calibration procedure, which will help the system correctly display the charge level, completely discharge the phone before turning off, then charge to 100% and hold on charging for another hour.
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Calibration of the power controller after the battery replacement is mandatory for the correct display of charge percentages and stable operation of the device.
In the early days of use, watch the heating temperature. The new battery may warm up a little during the first charge-discharge cycles, which is normal for pumping chemistry.
Regular use of original chargers will extend the life of the new battery, avoiding deep discharge to zero and trying to keep the charge in the range of 20% to 80% for maximum durability.