Declining autonomy is a natural process for any lithium-polymer battery, and the flagship Xiaomi Redmi 8T is no exception. Over time, the device begins to discharge faster, spontaneously turn off at a charge rate of 15-20% or charge for a long time, which signals physical wear of the battery's chemical composition. Owners often face the dilemma of buying a new smartphone or trying to extend the life of the current gadget by installing a new power system.
Replacing a battery on its own saves a significant amount of money compared to authorized service centers, where the cost of work can be half the price of a new part. However, this process requires accuracy, a specialized tool and an understanding of the internal workings of modern electronics. Misconduct can lead to damage to the plumes, bloating a new battery or even short circuit.
In this article, we will take a look at every step of the procedure, from the workplace preparation to the final calibration of the power controller, how to safely open the case, disconnect the plumes without risking them breaking, and correctly lock the new battery. It is important to understand that opening the case automatically deprives the device of warranty, so you should only start repairing if the warranty period has already expired or does not cover this type of malfunction.
Diagnostics and selection of a new battery
Before starting disassembly, you need to make sure that the problem lies in the physical wear of the battery, and not in software failures or a fault of the charging controller. Battery bloating is the most obvious sign, which is often accompanied by detachment of the back cover or the appearance of gaps in the body. If the rear panel of the Redmi 8T began to bend, it is strictly forbidden to operate the device, as this creates a risk of fire or further damage to the display matrix.
When choosing a new battery, the key parameter is its capacity and compatibility with a particular model. For the Xiaomi Redmi 8T (model M1908F1), the standard battery is a 4,000 mAh battery. There are many options on the market, but it is important to distinguish the original components from quality analogues and outright fakes. The original part is marked with the BM4B code, which can be found on the factory packaging or on the board of the old battery after removal.
Pay attention to the date of production: lithium polymer cells degrade even when stored, so a battery that has been in storage for three years will have a reduced life. A quality analog can be better than an expired "original." When buying, check for a protective circuit on the end of the battery - it prevents overheating and overcharging.
It is also worth considering that cheap copies often have real capacity for the product. 30-40% The use of these components will cause the problem of autonomy to return in a couple of months. BM4B nominal-capacity 4000 mAch and typical 3900 max 3.85Weight checks can also help: the original weighs around 45-48 gram, while cheap forgeries can be considerably easier due to material savings.
Tools and workplace preparation required
A minimal but specific set of tools will be required to make the repair work successfully; the use of inappropriate items such as knives or pins can cause permanent damage to the body and internal components; the main tool for opening the body will be a hair dryer or a heating platform, since the Redmi 8T back cover is glued to a durable polymer glue.
In addition to the heat source, you will need thin plastic cards or special mediators (scapula) to peel off the lid. Metal tools at this stage are dangerous to use, as you can damage the glass or cut your finger. To work with internal components, you will need a set of screwdrivers, mainly cross PH00 and PH000, as well as tweezers with thin curved ends to work with plumes.
- 🔧 Set of screwdrivers (cross-crosses) PH00, PH000, maybe Torx. T5)
- 🔥 Hair dryer or heating platform (temperature) 80-100°C)
- 💳 Plastic card, mediators or screen suction cup
- 🧲 Magnetic mat or organizer for screws
- 🧴 Isopropyl alcohol or special liquid B-7000 glue-removal
- 🧹 Brush and soft fabric for cleaning internal components
The organization of the workspace is a critical step. The screws in modern smartphones can vary in length and diameter, and putting a long screw in the hole for a short can break through the motherboard. It is recommended to use a magnetic mat or simply spread the screws on a piece of paper in the order of their extraction, signing the steps.
☑️ Preparation for repairs
Before starting the work, be sure to remove SIM-MicroSD card and memory card, if installed, and you also need to turn the device off completely, and work in good light, in a dry room, away from water sources. Static electricity can damage electronics, so it is advisable to use an antistatic bracelet or periodically touch a grounded metal object.
The process of disassembling the body Xiaomi Redmi 8T
The dismantling of the Redmi 8T begins with heating the perimeter of the back cover.The glue that locks the glass becomes plastic at about 80-90 degrees Celsius.Heat the edges evenly, avoiding prolonged exposure to one point so as not to overheat the internal components or the battery itself, which can be dangerous.
After the case is warmed up (usually 2-3 minutes of hair dryer), attach a suction cup at the bottom of the back cover and slightly pull up, creating a gap. Insert a plastic mediator into the resulting gap carefully. Move the map along the perimeter, cutting the glue layer. Be especially careful in the upper part of the smartphone, where the plumes are located, and in the area of the camera module.
⚠️ Warning: Do not try to open the case if it is still cold. Excessive force will lead to cracks in the glass of the back cover, which then have to be changed whole with the frame.
Once the lid is removed, don't move it far unless you plan on gluing it back right away -- the old glue will have to be removed. Now you have access to the insides. The first thing you need to do is to disconnect the battery plume from the motherboard, and this is done by unscrewing the protective metal plate that covers the connectors.
Use a PH00 screwdriver to unscrew the screws that hold the metal bar over the battery connector. After removing the bar, gently disconnect the battery plume, putting a plastic blade or nail on it, and only after the power is turned off can the other screws be unscrewed and other plumes, including the display and touchscreen, be disconnected.
- 🔥 Warm up the perimeter of the body during 2-3 minute
- 🔪 Carefully disconnect the cover with the mediator in a circle
- 🔌 Unscrew connector protection and turn off the battery
- 🔩 Unscrew all the screws holding the frame (usually near them). 10-12 piece)
Then you have to take out the main board. It can be locked in the slots, so you can do it without jerking. Often, the Redmi 8T board has a plume going to the bottom board (where the charging connector is), which you also need to gently disconnect. Once you remove the board, you can access the battery itself, which is usually fixed to double-sided scotch or glue strips.
Removing the old battery and installing a new battery
Replacing the power supply is the most critical moment. The battery in Xiaomi Redmi 8T is glued to the plastic frame quite firmly. Under no circumstances do not try to tamper with a metal screwdriver or a knife - a puncture of the lithium polymer cell causes instant ignition and the release of toxic smoke.
To extract it safely, use a plastic card that needs to be moistened with isopropyl alcohol. Spend the card under the battery, gradually separating it from the base. If you use a system of adhesive stripes (like the iPhone), you can try to pull them out with tweezers, but in budget Xiaomi models, most often a solid layer of glue is used, in which case it helps to carefully warm the back of the case with a hairdryer already in disassembled condition.
What to do if the battery does not detach?
After removing the old element, thoroughly clean the seat of glue residues. The surface should be flat and clean so that the new battery fits tightly and does not hang inside the housing. Degrease the surface with alcohol and let it dry. If the new battery has adhesive tapes, use them. If not, you can apply a thin layer of special B-7000 glue to the edges of the seat.
When you install a new battery, make sure that the plume connector matches the back end of the board. Don't put too much effort into connecting -- the connector should stand in place with a slight click. Once the plume is connected, take your time to assemble the case completely. First, check if the phone is turning on and if it sees charging.
| Parameter | Original | Quality analogue | Cheap copy |
|---|---|---|---|
| Capacity (real) | 3900-4000 mAh | 3500-3800 mAh | 2000-2500 mAh |
| Cycle resource | 500+ cycles | 300-400 cycles | 100-150 cycles |
| Protection | Complete. | Basic | Often absent |
| Price. | Tall. | Medium | Low. |
It's important to place the plume properly so that it doesn't clamp when you put the back cover in. Often, the battery comes with adhesive strips to hold the tail of the plume to the body or the battery itself -- use them, and that will prevent contact from drifting away when the phone falls in the future.
Assembly of the device and check of performance
Before the final assembly, you need to check the performance of all systems. Connect the display plume and the battery, then press the power button. If the screen catches fire and the phone starts to load, the first stage is successful. Check the touchscreen, speakers, microphone and cameras, because if you build it in a sloppy way, you could damage the corresponding plumes.
Make sure the charging light is on when you connect the cable. If the phone is switching on but not charging, check the connection density of the battery connector and the charging board plume (bottom module), sometimes you need to reconnect the plume connecting the main and bottom boards.
⚠️ Warning: If the phone doesn't turn on after assembly, don't panic. It might be a controller that's gone out or the protection's gone off. 15-20 minutes, then try to turn it on again.
If all functions are working correctly, start the final assembly. Put the metal connector protective plate in place and twist all the screws. Make sure that no screw is left over - there are no unnecessary parts in the Xiaomi design. When installing the back cover, apply a new layer of glue or use special adhesive tapes around the perimeter to restore moisture protection (at least partial) and fixation.
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For better adhesion of the new adhesive, warm the edges of the body with a hairdryer slightly before sticking the lid, which will activate the adhesive and provide a more reliable connection.
Press the perimeter cap and lock the device with money bands or clamps (neatly, through the fabric) for 1-2 hours until the glue is completely dry. Do not turn the phone on during the gluing process, so as not to disturb the geometry of the case.
Calibration and first launch
Once a new battery is installed, the power management system may not correctly display the charge level, because the controller remembers the parameters of the old, degraded element, and to work properly, you need to perform a calibration procedure, which will help the system accurately determine the percentages and work correctly energy saving algorithms.
The first charge is recommended when the phone is turned off. Connect the original charger and leave the smartphone to charge to 100%. After the indicator shows a full charge, do not turn off the cable for another 1-2 hours. This will allow the balancing controller to equalize the voltage in all banks of the battery.
- 🔋 Discharge the phone until it is completely turned off (0%)
- 🔌 Put on charging in the off state to 100%
- ⏳ Keep it on the charger for more. 1-2 half-hour
- 🔄 Turn on your phone and use it normally until discharged.
- 🔁 Repeat the charge-discharge cycle 2-3 time-calibration
In the process, try not to bring the lithium polymer battery to deep discharge regularly. The optimal range for extending the life of the battery is from 20% to 80-90%. Although modern MIUI controllers do a good job of protection, the habit of putting the phone on charge overnight or holding it on a wire can accelerate the degradation of a new cell.
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Proper calibration in the early days of use allows the power controller to accurately read the capacity of the new battery, eliminating percentage spikes and sudden shutdowns.
If you see rapid discharge or heating in the area of the chamber after calibration, there may be a defective battery or the problem is in the software, in which case it is worth checking the battery usage statistics in the settings or contacting a specialist for a diagnosis of current consumption.