The Xiaomi Mi 9T Pro, known globally as the Redmi K20 Pro, has earned a reputation as one of the most balanced devices of its generation. However, time does not spare chemical batteries, and after a few years of active use, battery capacity inevitably decreases, leading to rapid discharge and unexpected outages. Owners often face the dilemma of carrying the device into service or trying to replace the battery on their own, saving money.
The repair process of this smartphone is technically difficult due to the use of a retractable front camera, which requires accuracy when dismantling the case.You will need not only a new power source, but also a specialized set of tools, as well as attention to detail. In this article, we will discuss each step of the work in detail so that you can safely return the gadget to factory autonomy without damaging the fragile plumes.
Preparation of the workplace and selection of components
The ideal solution is to have a spacious table with good lighting and an antistatic mat, although you can do without a pile. It is critical to have a magnetic mat or screw containers ready, because the Mi 9T Pro uses different lengths of fasteners, and confusing them is a risk to the integrity of the motherboard.
The choice of a new battery is the foundation of the success of the whole event. The Roll is oversaturated with fakes, so when buying, pay attention to the presence of holograms, the quality of printing barcodes and the compliance of the declared capacity of 4000 mAh. The original part should have a voltage of 3.85V and the corresponding serial number, which can be checked through the engineering menu or special diagnostic applications.
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Buy the battery only from trusted suppliers who guarantee that there will be no bloating during the first months of operation. Cheap analogues often lose capacity after six months.
To work, you will need the following set of tools, without which safe disassembly is impossible:
- 🔧 Torx screwdriver set (T5, T6) cross-block (PH000) screw-breaker.
- 🌡️ Thermostole or hair dryer to soften glue under the back cover.
- 🧩 Plastic blades and mediators for accurate opening of the body.
- 🧲 Magnetic substrate for sorting screws by disassembly stages.
Rear panel removal and protection of internal components
The back cover of the Xiaomi Mi 9T Pro is glued around the perimeter to a double-sided scotch that requires heating to soften. Turn on the hair dryer at a medium temperature (about 80-90 degrees) and evenly warm the perimeter of the device for 2-3 minutes, avoiding hot air directly on the screen so as not to damage the matrix. After heating, insert a plastic suction cup at the bottom of the body, slightly pull up, creating a gap, and gently enter a thin plastic blade.
Move the blade along the edges, gradually cutting through the adhesive layer, but be extremely careful at the top of the smartphone. This is where the fingerprint scanner plumes (if any) and other sensitive connections are easily damaged by careless movement. Once the lid is separated, do not immediately try to remove it completely - first make sure that no cables connect it to the main board.
⚠️ Warning: Never use metal tools (knives, needles) to slam the lid as this is guaranteed to short-circuit or puncture the old battery, which can cause a fire.
Once you successfully remove the back panel, you will have access to the insides of the device, which are covered by a protective plastic plate, which covers the main board, the battery and the plume connectors. To remove it, you need to unscrew all the visible screws, the number of which can vary depending on the regional version of the device. Some screws can be hidden under stickers or rubber plugs, so carefully examine the surface.
☑️ Check before removal of protection
Disconnecting plumes and removing the old battery
When you remove the safety plate, you have full access to the motherboard and the battery. The first and most important step is to turn off the device. Find the connector connecting the battery to the board, and gently disconnect it with a plastic blade or nail, only then you can safely touch other connectors and components, eliminating the risk of short circuit.
The battery itself in the Redmi K20 Pro is fixed by a powerful adhesive layer at the bottom of the frame. To extract it, it is recommended to use special pull-out tapes that are laid under the battery by the manufacturer. If the tapes are broken or missing, you can gently tweak the edge of the battery with a plastic card, preheating the back of the smartphone slightly to the thermostole to 40-50 degrees.
| Parameter | Original | Quality copy | Cheap analogue |
|---|---|---|---|
| Capacity | 4,000 mAh | 3800-4000 mAh | 2500-3000 mAh |
| Tension. | 3.85V | 3.85V | 3.7V - 3.8V |
| Thickness | Standard | Standard | Often bloated |
| Cycle resource | 800+ | 500-600 | 200-300 |
When working with the battery, avoid deformation of the battery housing. A puncture of the lithium polymer battery will cause instant ignition and the release of caustic smoke. If you notice that the old battery is swollen, act with the utmost care, not pressing it with sharp objects.
What to do if the pulling tapes are broken?
Installation of a new battery and assembly of the device
Before installing a new battery, you need to carefully clean the seat of the residue of old glue, use a plastic blade and, if necessary, a little isopropyl alcohol to achieve a perfectly flat surface, which will ensure that the new battery fits tightly and prevent it from displacing or bloating in the future.
Apply a new layer of bilateral glue or special adhesive strips to the body, then carefully install the battery, combining the connector. Connect the battery plume to the motherboard before a characteristic click, making sure the contact is reliable. Do not turn on the device immediately - first check visually all connections and make sure that no plumes are compressed.
The assembly process is reversed: Place the safety plate, twist all the screws to their original length (longer ones usually go along the edges), then plug in the test plume or gently press the back cover for an initial health check before sticking it permanently.
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Proper cleaning of the seat from old glue is a guarantee that the new battery will lie flat and will not be subject to mechanical pressure, which reduces its service life.
Initial start and calibration of the battery
After the new element is physically installed, you need to do the correct initial charging, plug in the original charger and leave the smartphone to charge up to 100% when it is off, allowing the power controller to correctly determine the capacity of the new battery and calibrate the readings.
Turn on the device and check the percentage of charge. If the smartphone shows 1% or does not turn on, it may be that the connector is not fully inserted or the protection is activated. In this case, disconnect the battery for 10-15 seconds and connect again. It is also recommended to perform a full charge-discharge cycle: discharge the phone before turning off and recharge to 100%.
To diagnose the state of the new battery, you can use an engineering menu MIUI. Enter the code ##6485## In the phone app and pay attention to the parameters MB_06 (battery status; and MF_02 (Number of charge cycles. For a new battery, the state should be "Good" and the cycles should be minimal.
Possible problems and ways to solve them
Even with a careful assembly, there can be unforeseen situations. If the smartphone does not respond to the on button after replacing, check the voltage on the battery contacts with a multimeter - it should be within 3.7-4.2 Volts. Often the problem lies in an oxidized connector or insufficient contact that can be corrected by reconnecting.
Another common problem is the system reporting an "Unlicensed Battery" or a quick discharge, which may indicate a poor quality of the purchased component or the need to reset the power controller, and in some cases, a long connection to the charger (up to 12 hours) when turned off helps.
⚠️ Note: If you have damaged the main camera or display plume during operation, do not try to glue it together. Such damage requires a complete replacement of the module, since it is impossible to restore the conductors at home. In case the phone starts to heat up quickly in standby mode, check if the battery plume is squeezed by a protective plate.Mechanical damage to the insulation can lead to micro-circuiting that is dangerous to the device. Always do the final temperature check before the final sealing of the enclosure (FAQ) Can I replace the Xiaomi Mi battery? 9T Pro without removing the display? 9T The Pro allows you to replace the battery through the back cover. No display module is required to remove, which reduces the risk of damage to the screen, which in this model is one of the most expensive components. Do you need to glue the back cover to a special glue? Yes, using the B-7000 or the original adhesive layer is necessary to restore moisture protection (at least partial) and prevent backlash of the cover. Without the glue, dust and moisture will enter the inside. Why does the battery discharge faster than before? This may be due to the calibration of the system or the failure of the battery itself. Try to perform a full charge-discharge cycle. If the problem persists for more than 3-5 days, you probably have a poor copy with the real capacity below the declared one. Does the battery discharge discharge discharge discharge more delicately, and cause this battery to be damaged by the battery to the heat?