The Xiaomi Mi 8 Lite, launched in 2018, is still a popular device due to its stylish design and balanced performance. However, time is not spared by lithium-ion power supplies, and after several years of active use, owners begin to notice a sharp drop in autonomy. The phone discharges in a couple of hours, turns off in the cold or shows the wrong percentage of charge – all these are sure signs that the battery life is exhausted.
You can replace the battery yourself if you have basic electronics skills and a set of tools. It's important to understand that the procedure requires care, because the body is made of glass and metal, and the internal components are quite tight. Incorrect actions can damage the plumes or break the back cover, so carefully study the algorithm of actions before starting work.
In this article, we will discuss in detail the process of matching the compatible battery, preparing the workplace, the stages of disassembling the case and then calibrating the new battery. You will learn how to safely disconnect old components and install new ones, avoiding typical errors. Properly carried out procedure will return your gadget to a second life and ensure comfortable use throughout the day.
Diagnostics and selection of a new battery
Before you start disassembling, you need to make sure that the problem lies in the physical wear of the chemical element, and not in software failures or malfunction of the power controller. Android has hidden menus to assess the power status, but the most accurate method is visual inspection after opening and testing with a load plug. If the battery is swollen, lost more than 20% of its rated capacity or the phone turns off at 30-40% of the charge, replacement is inevitable.
When choosing a new part for the Xiaomi Mi 8 Lite, it is critical to pay attention to the labeling and capacity.The original capacity of the model is 3120 mAh. The market is crowded with cheap counterparts that can have a real capacity of half the declared one. A quality battery should have a protective board with a controller that prevents overheating and overcharging.
Do not chase record 4,000+ mAh capacity in the format (original size) - it is physically impossible to fit such energy into the dimensions of the standard compartment without changing the chemistry or packing density, which often leads to a decrease in reliability.
- 🔋 Capacity: Look for a marking of 3120 mAh (nominal) or 3200 mAh (typical).
- 🏷️ Marking: model BM3E — This is the standard code for the Mi 8 Lite.
- 🛡️ Protection: the presence of a hologram of the manufacturer and QR-authentication.
- 📏 Dimensions: thickness should not exceed the original, otherwise the cover will not close.
⚠️ Warning: If you find that the old battery is very swelled and presses on the display or back cover, act with utmost care.
Tools and workplace preparation required
The quality of the repair starts with the right organization of the space: you need a clean, well-lit surface, free of static electricity. Ideally, you can use an antistatic mat, but you can also use a regular wooden table with a clean cloth. Before starting work, be sure to turn off the smartphone and remove SIM-map.
The Xiaomi Mi 8 Lite will require a specific set of tools to disassemble, since the device does not have screws outside the body. The main fastener is under the adhesive layer and inside the case. You will need suction cups to open the case, thin plastic mediators (scapula), a set of Phillips screwdrivers (cross) of different sizes, tweezers and thermophen or a hot water heater to soften the adhesive.
It is also recommended to prepare the screw folding tank so as not to lose them in the process. Small parts, such as plugs or fasteners, it is better to put immediately in a separate organizer. The use of metal tools inside the case is extremely undesirable, since you can accidentally close contacts on the motherboard.
☑️ Checklist for repair preparations
The process of disassembling the body Xiaomi Mi 8 Lite
The most difficult step of replacing is to carefully remove the back glass cover. It's glued around the perimeter to a double-sided tape. To soften the glue, you need to warm up the perimeter of the device evenly. Use a thermophen or electric heating pad, setting a temperature of about 80-90 degrees. It takes 2-3 minutes to heat up, constantly checking the heating with your finger - the glass should not be too hot to burn or burst from the temperature drop.
After warming up, attach the suction cup to the bottom of the back cover, closer to the edge. Pull the suction cup up, creating a gap, and insert a plastic mediator into the resulting gap. Drive the mediator along the perimeter, cutting the adhesive layer. Move slowly, trying not to plunge the blade deep inside, so as not to damage the plume of the fingerprint scanner, which is glued to the inside of the lid.
Be very careful at the bottom of the smartphone, where the fingerprint sensor plume passes. Don't pull the lid back too far until you unplug the plume. Carefully lift the edge of the lid, find the fingerprint scanner connector and unplug it from the motherboard, and then you can remove the back panel completely.
Next, you need to unscrew the screws that lock the protective plate that covers the main plumes and the battery, usually a few screws around the perimeter of the board and 1-2 screws at the bottom that hold the bottom board. Use a magnetic screwdriver or tweezers to avoid dropping the screws inside the case.
What to do if the lid does not open?
Removing the old battery and installing a new one
Once the protective plates are removed, you will have access to the battery. In the Xiaomi Mi 8 Lite, the battery is glued to the frame of the case with special adhesive strips. Under no circumstances do not try to tamper with metal objects or bend it strongly - this can lead to short circuits and fire. Use a plastic card or a special blade with a notch for safe extraction.
First, disconnect the battery connector from the motherboard. Then, gently putting the plastic tool under the end of the battery, gradually separate it from the adhesive layer. If the battery is sitting very tight, you can warm the area under the battery a little through the screen (if it is removed) or through the frame, but carefully so as not to overheat the display matrix. Some masters use special adhesive solvents, but at home it is better to do mechanical action with warming up.
The new battery is set in reverse order. Before sticking, make sure to check if the new battery connector matches the socket on the board. If the new battery has adhesive strips (b-7000 or double-sided tape), apply them to the case. It is strictly forbidden to use superglue or other cyanacrylate adhesives, as their pairs can damage the optics of cameras and sensors, and the glue destroys plastic and lithium.
Once the battery is installed, plug the plume into the motherboard before the characteristic click. Make sure the connection is reliable. Now you can temporarily (without screws) install the protective plates and try to turn the device on by pressing the power button. If the phone is on and shows the charge, then the installation was successful.
- 🔌 Disable the battery plume before any manipulation of the boards.
- 🧹 Clean the frame of the case of the remnants of old glue before installing the new tape.
- 🧪 Degrease the frame surface with alcohol for better adhesion of the new battery.
- 🔍 Check the integrity of the new battery’s insulation before installation.
⚠️ Warning: If the new battery comes with a discharged voltage (less than the current) 3.0 B), the phone may not turn on right away. Leave it on charging on 15-20 minutes without trying to turn on.
Assembly of the device and check of performance
Once you make sure that the smartphone is on and responsive to charging, you can start the final assembly. Put all the protective metal plates in place and twist the screws. It's important not to pull the screws, especially those that are fixing the board, so as not to break the thread in the plastic bushings. Spread the screws correctly: usually longer ones go to the corners, and short ones go to the center.
Connect the fingerprint scanner plume to the motherboard. Make sure the plume is flat, no cracks. Then apply a new adhesive layer to the frame to fix the back cover. You can use a special glue B-7000, applying a thin strip around the perimeter, or a ready-made double-sided tape cut out in the shape.
Apply the back cover, combining all the holes and faces. Press tightly around the perimeter. For better fixation, it is recommended to put the phone under the press (for example, under a stack of books) for 1-2 hours until the glue is completely polymerized. After drying the glue, wipe the case from the glue residue and check all the functions: touchscreen, speakers, microphone and cameras.
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Use rubber harnesses or stationery gums wrapped around the assembled phone to ensure uniform pressure on the cover during glue drying.
Calibration and features of operation
After the battery is replaced, the Android system may not display the charge level correctly, since the power controller has not yet "meeted" the new battery. To calibrate, you need to conduct a full charge-discharge cycle. Discharge the phone until completely turned off (0%), then charge it when turned off to 100%. After reaching 100%, hold on charging for another hour.
Turn on the phone and use it normally until it is fully discharged again. Repeat the procedure 2-3 times. This will help the controller remember the real limits of capacity and voltage. In modern Xiaomi smartphones with a MIUI shell, it is also useful to reset battery statistics through engineering menus or special applications, although a full cycle usually solves the problem.
To extend the life of a new battery, try not to let the phone run deep to zero and keep it constantly on charge 100%. The optimal range for lithium-ion batteries is from 20% to 80%. Also avoid using your smartphone while charging, especially when playing resource-intensive games, as heating is the main enemy of the battery.
| Parameter | Original | Quality copy | Cheap forgery |
|---|---|---|---|
| Capacity | 3120 mAh | 3000-3100 mAh | 1500-2000 mAh |
| Cycle resource | 500+ cycles | 300-400 cycles | 50-100 cycles |
| Protection | Complete. | Basic | Absent. |
| Price. | Tall. | Medium | Low. |
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Proper calibration in the first days of use is the key to accurately displaying the percentage of charge and long service of the new battery.