Modern Xiaomi smartphones, such as the popular Redmi Note, Mi and POCO series, are equipped with non-removable lithium-polymer batteries. This design solution allows manufacturers to make the case thinner, tighter and increase battery capacity due to dense layout. However, over time, usually after 2-3 years of active use, the capacity of the chemical cell decreases, the phone begins to quickly discharge or turn off in the cold.
Many users mistakenly believe that a fixed means that you can't replace it at home, but in fact, this only indicates that access to the battery requires partial or complete disassembly of the case using a special tool and heating appliances, a process that requires accuracy, but is feasible with the availability of theoretical training.
Before you start physical intervention, you need to assess the risks. Self-replacement will deprive you of the official warranty if it has not expired. In addition, inept actions can damage the display plumes or break the charging plume. If you are not confident in your abilities, you better contact an authorized service center, but if you decide, follow the instructions as accurately as possible.
Tools and workplace preparation required
To replace the power supply properly, desire alone is not enough. You will need a specialized set of tools, which is often sold as a smartphone repair kit. It is critical to prepare a heating element, since modern Xiaomi phones are assembled with glue. A regular hair dryer will not work due to the low flow temperature, so it is better to use a temperature-adjusted building hair dryer or a professional heat pad.
The second important aspect is safety: Lithium polymer batteries are sensitive to puncture and overheating, should only work on a clean, dry surface, away from flammable objects, be sure to remove metal jewelry from your hands so that you do not accidentally close the contacts of the motherboard if the device is partially assembled.
- 🛠️ Precision screwdrivers (cross-hatched) P2, P5 and flat) for screw twisting.
- 🔥 Building hair dryer or heating pad for heating the perimeter of the case to 80-90 degrees.
- 💳 Plastic card or mediator for neat opening of the case without scratches.
- 🧲 Magnetic mat for sorting screws of different sizes.
- 🧤 Antistatic gloves to protect components from static electricity.
⚠️ Note: The use of metal blades to open the case is strictly prohibited - this is guaranteed to lead to rupture of plumes or damage to the display.
Pay special attention to lighting. Small screws and connectors are not visible in dim light, which increases the risk of error. If you have a magnifying glass or a magnifying glass, use them to inspect the internal components before starting work.
Diagnosing the state of the battery before replacement
Before you disassemble the phone, make sure that the problem lies in the wear of the battery, and not in the software failure or malfunction of the power controller. In the shell of MIUI (and its successor HyperOS) there are built-in diagnostic tools that allow you to assess the current state of the system without third-party software.
To start the engineering menu, enter the code in the “Phone” application ##6485##. In the list of parameters you are interested in items that begin with MB_ or BAT_. For example, a parameter MB_06 The battery state is indicated, and MB_00 — If the system says "Good" but the phone lives 2 oh, it may be calibration misplaced or physical wear, but the controller has not yet recorded a critical error.
It’s also worth checking the usage statistics in the Settings → Battery and Performance menu. If you see that background processes are consuming energy abnormally, it’s possible that the problem will be solved by resetting the settings or removing the “heavy” application, and you won’t need to replace the hardware.
Xiaomi’s Hidden Diagnostics Codes
The process of disassembling the Xiaomi smartphone
The beginning of the work is always the same: you need to get SIM-The tray is not to damage it when it is heated. The phone is then turned off completely. Heat the back cover around the perimeter for 2-3 minutes, constantly checking the temperature with your finger to avoid overheating the glass or plastic. The optimal temperature is when the body is hot to hold, but there is no burn yet.
After heating, insert the suction cup into the bottom of the back cover and pull slightly, creating a micro-gap. In this gap, gently insert a plastic mediator and start running it along the edges, cutting the adhesive layer. Don't try to tuck the lid in one place - the adhesive needs to be "flake off" sequentially throughout the circuit.
☑️ Safe Disassembly Algorithm
When the lid is removed, you'll see a metal plate covering the motherboard, and it's attached with a lot of screws of different lengths, and it's important to remember or photograph the location of each screw, because screwing a long screw into a short hole can break the board and put the phone out of action forever.
Once the metal shield is removed, you can access the main modules, and the first thing you do is turn off the battery connector, and this is done with a plastic blade or a nail, putting the connector up from the bottom up, and only after the battery is turned off, you can touch the other plumes, because this will turn off the device and eliminate the risk of short circuit.
Removing the old and installing a new battery
Xiaomi smartphones typically have a double-sided tape on their battery, which you can't remove on dry -- you can damage the cell shell, which will cause fire. There's a proven method: put a plastic card on the edge of the battery and put a little isopropyl alcohol (not water or acetone!).
The alcohol will dissolve the glue, and the battery can be removed effortlessly. If the battery is too swelled, act with utmost care: any pressure can damage the internal separator. In such cases, it is better not to use sharp objects at all, but soak the glue with alcohol until completely released.
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Use isopropyl alcohol 99% concentration. It does not conduct current and quickly evaporates, leaving no moisture inside the case, unlike vodka or cologne.
The new battery must be original or high-quality copy (High Copy). Before installation, clear the seat of the residue of old glue and apply new strips of double-sided tape (B-7000 or special stickers). Set the battery, press it tightly and connect the plume to the characteristic click.
| Characteristics | Original | Quality copy | Cheap forgery |
|---|---|---|---|
| Weight. | It is consistent with the stated | 5-10% lighter | Much easier. |
| Font marking | Clear, smooth, not washed | Possible micro-inaccuracies | Blurred, smeared |
| QR-code | It's scanned. | Often not read. | Missing or fake |
| Cycle resource | 500+ full cycles | 300-400 cycles | 100-150 cycles |
When you're connected, don't rush to close the lid, turn on your phone and check if the charge is going, if the battery percentage is displayed correctly, and if everything works, you can start the final assembly.
Assembly of the device and checking leakage
You do the reverse assembly. You put the metal shield in, you twist all the screws according to the pattern, then you apply a new layer of glue, or you use special tapes around the perimeter of the case to restore the leakage, press the back cover and lock it with rubber bands for 15 to 20 minutes before the glue drys out.
After assembly, you need to do a primary calibration. Discharge the phone to 0% (until it turns off), then charge it when it's off to 100%. Then turn it on and check it out, which will help the power controller "understand" the real capacity of the new element.
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Proper calibration after battery replacement extends its life and ensures an accurate display of the percentage of charge in the system.
Check all the sensors, cameras and speakers, and if your fingerprint or proximity sensor stops working after you build it, you may have pressed the plume badly or damaged it when you build it, and you'll have to repeat the procedure.
Typical errors and security measures
One of the most common mistakes is ignoring the heating of the case: trying to tear the lid by force causes cracks in the glass; another mistake is using a soldering iron next to the battery; high temperatures can instantly ignite electrolyte vapors inside the cell.
Also, users often forget to turn off the battery before disconnecting other plumes, which can cause a voltage surge and fuses on the board to burn, and always remember: the battery turns off first, the battery plugs in last.
⚠️ Warning: If you smell a sharp chemical smell or see smoke, stop working immediately, take the device out into the open and fill it with sand!
Do not try to charge the phone if it warms more than 40 degrees in the battery after replacement, which is a sign of an internal short circuit or a defect of a new cell.