How to replace the battery Xiaomi Mi 9T Pro: the full guide

Smartphone Xiaomi Mi 9T Pro has established itself as one of the best flagships of the mid-segment, but time does not spare lithium-polymer batteries. After two or three years of active operation, the battery capacity inevitably drops, the device begins to discharge in a couple of hours or suddenly turn off in the cold. Many owners are thinking about self-repair to return the gadget to its former autonomy without contacting the service center.

The battery replacement process in this model has its own characteristics related to the design of the case and the location of the plumes. Unlike many modern devices, it has a mechanical pop-up camera module, which requires special care when dismantling. Proper preparation and understanding of the sequence of actions will allow you to successfully complete the procedure and save a significant amount of money.

In this article, we will take a look at every step of the way, from the selection of components to the final assembly, and you will learn what tools are really needed, how to safely unplug the back cover and what to look for when you connect a new battery. Importantly, before you start work, be sure to turn off your smartphone to avoid short circuits.

Diagnostics and selection of a new battery

Before starting to disassemble, you need to make sure that the problem lies in the wear of the chemical battery. If the phone quickly discharges, warms up or “jumps” the percentage of charge, most likely, the resource is exhausted. Xiaomi Mi 9T Pro (model M1903F11G) uses a battery model BM4J with a rated capacity of 4000 mAh.

When buying a new part, it is important not to run into a fake. The market is full of low-quality copies that can swell in a month of use. Pay attention to the quality of the logo printing, the presence of holograms and barcodes that should match the number on the battery board itself.

• 🔍 Check the production date: Lithium polymer batteries degrade even when stored, so don't take parts older 1-2 years.
• 🔍 Compare weight: the original battery has a strictly defined mass, a strong deviation in the lower direction indicates a smaller capacity.
• 🔍 Look. QR-code: on original Xiaomi parts, the code must be read by the scanner and match the information on the package.

Don’t skimp on components, as a poor-quality battery can damage the power controller or, in the worst case, cause a fire.The original part will ensure the manufacturer’s declared autonomy and correct operation of the Quick Charge 4+ fast charging system.

Tools and workplace preparation required

A minimum set of specialized tools is required to make a successful repair. Use of improvised tools such as knives or pins is strongly discouraged, as there is a high risk of damage to internal components or injury. Organize a workspace in good light to see small screws and plumes.

You'll need a dryer or a thermal film to heat the glue, and a suction cup or a thin mediator to snap the case off. All screws are better folded in a magnetic mat or spread out on a sheet of paper marked out, as they may differ in length and type of thread.

Pay special attention to the integrity of the tools. A scratched metal spatula can close contacts on the board, so it is preferable to use plastic analogs, and prepare a container for small parts so that nothing is lost in the process of work.

⚠️ Warning: Only work on a clean, dry and non-conductive surface. Static electricity can disable electronics, so it is advisable to use an antistatic bracelet or periodically touch a grounded metal object.

Removal of the back cover and removal of protective elements

Start the disassembly process by heating the perimeter of the back glass panel, the glue that holds the lid softens at about 80-90 degrees Celsius, warm the edges evenly for 2-3 minutes, avoiding prolonged exposure to the center part where the battery is located.

After heating, gently insert the suction cup into the bottom of the back cover, closer to the charging connector, and pull up slightly to create a gap. Insert a plastic blade or mediator into the resulting gap and run it along the perimeter, cutting the adhesive layer. Move smoothly, without sharp jerks, so that the glass does not crack.

• 🔥 Do not heat the case too much: if holding the phone in your hands becomes uncomfortable, pause to avoid damaging the display or internals.
• 🔥 Be careful with the fingerprint scanner: it is located on the inside of the cover and is connected by a thin plume to the motherboard.
• 🔥 Disconnect the scanner plume immediately after removing the lid before placing it on the table to avoid damaging the contact.

Once you remove the lid, you'll see a black plastic panel covering the bulk of the components, and it's screwed with a few screws around the perimeter and in the center, unscrew them all using the appropriate screwdriver, and carefully remove the protection to access the battery and the plumes.

Disconnecting the plumes and removing the old battery

Before you can remove the battery, you need to turn off all the plumes that go to the motherboard, which is a critical step, which requires maximum concentration, first you disconnect the connector of the battery itself to turn off the device, and then all the other plumes of the display and cameras.

The battery in Xiaomi Mi 9T Pro is planted on double-sided tape, which over time becomes very durable. Under no circumstances do not try to tamper with the battery on the upper edge with metal tools - a puncture of the lithium element causes instant ignition. Use special hoods, suction cups or plastic card, putting the battery on the bottom.

To make things easier, you can warm up the battery area with a hairdryer, but be very careful not to swell the battery itself. If there are plumes under the battery (in this model they go under it), be careful not to damage them when you remove them.

Once the old element is removed, clear the seat of the residue of the old glue. The surface should be flat and clean, so that the new battery lay tight and does not shift during operation of the device.

Installation of a new battery and assembly of the device

You can use special adhesive tapes to repair smartphones or high-quality double-sided 3M tape on the new battery. Apply the adhesive evenly, avoiding overlapping contacts and areas where the plumes pass.

Put the battery back in place, making sure the connector matches the connector on the board. Carefully press the battery over the entire area for a secure lock. Now you can move on to connecting the plumes, first the battery connects, then the display and the rest of the components.

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Before you finish building, check the phone's performance, turn it on, make sure it's charging responsive, touchscreen and cameras are working, and if everything's working, turn off the phone and continue building.

Put a plastic safety panel in place and twist all the screws. Don't pull the screws over because you can damage the thread in the plastic racks. Make sure all the screws fall into place and the panel doesn't backfire.

Apply a new layer of glue around the perimeter of the back cover or use a special adhesive frame, which will ensure the sealing of the case and protection against dust. Press the cover and lock the device with rubber rings for 15-20 minutes before the glue is fully grasped.

First start and calibration of the battery

Once assembled, turn on your smartphone. The system can boot a little longer than usual, as the primary initialization of the power controller is underway, check if the correct percentage of charge is displayed and if the charging process is underway.

To properly operate the battery indicator, it is recommended to calibrate the device completely before turning off, then charge it to 100% when turned off. After reaching full charge, keep the phone charging for another 1-2 hours.

⚠️ Attention: In the first few charge-discharge cycles, the controller may be showing incorrect percentages. This is normal, the system gradually learns and calibrates the new capacity.

If the phone turns on, holds a charge and correctly displays battery information, the replacement can be considered a success. Now your Xiaomi Mi 9T Pro is ready again for active operation without the need for constant recharging.

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Proper calibration in the first days of use extends the life of the new battery and ensures the accuracy of the charge display.

Frequently Asked Questions (FAQ)