Xiaomi Mi 8 Lite has come to market as one of the most attractive offers in the mid-range price segment, but time does not spare lithium-polymer batteries. If your device began to run out in a couple of hours, spontaneously turn off when charged at 30-40% or the glass of the rear cover is swollen, then it is time to replace the battery.
Before you start any manipulations, you need to understand that the Mi 8 Lite does not have a removable back cover, so the disassembly process will be quite time-consuming. You will need not only a new power source, but also a set of special tools, as well as patience. Incorrectly performing actions can damage the display plumes or puncture the old battery, which is fraught with fire.
In this article, we will discuss in detail the process of preparing the workplace, dismantling old components and installing a new power module. We will pay special attention to the nuances of working with adhesives and thin plumes characteristic of the design of this smartphone.
Diagnostics and workplace preparation
Before you take apart the Xiaomi Mi 8 Lite, make sure that the problem lies in the wear of the chemical element. Software failures can sometimes simulate a quick discharge, so it is worth checking the usage statistics in the Settings → Battery → Consumption menu. If the discharge schedule looks linearly steep or jumps in percentages, a physical replacement is inevitable.
The organization of the workspace is a critical step: you need a table with good lighting, preferably daylight or from a bright lamp with cold light, the surface must be clean, dry and, crucially, not conduct static electricity. An antistatic mat is ideal, but you can also use a regular wooden board or a clean sheet of paper.
To work with the Mi 8 Lite, you need a specific set of tools that you don't always have in your home medicine cabinet. Lack of the right screwdriver can lead to licking of the screw faces, and the use of metal blades can lead to a short circuit. Prepare everything you need in advance so that you do not interrupt the search process at the most critical time.
- 🔧 A set of precision screwdrivers (required presence of Torx) T5 cross-sectional PH000).
- 🔥 A hair dryer or heating pad for heating the adhesive layer (temperature near 80-100 degree).
- 🛠 Plastic blades and mediators for opening the body without damage.
- 🧲 Magnetic mat or organizer for sorting screws of different sizes.
- 💧 Isopropyl alcohol or special solvent of glue (B-7000) cleaning.
⚠️ Warning: Never use a metal knife or blade to smack the back cover around the plumes. In the Xiaomi Mi 8 Lite, the display plume runs around the perimeter, and damage to it will cause stripes to appear on the screen or the matrix to completely fade out.
The process of disassembling the smartphone body
The beginning is always the same: you need to remove the tray SIM-It's standard procedure for all modern smartphones to access the insides. In the Mi 8 Lite, the tray is on the bottom end, to the left of the charging port. Use a clip or a special needle, pressing the hole before you click.
The most difficult step is to separate the back glass cover, which is glued around the perimeter with a powerful adhesive compound that softens only when exposed to temperature. The heating should be uniform; do not hold the hair dryer at one point for longer than 3-5 seconds so that the glass does not crack from thermal shock. The optimal surface heating temperature is about 80 degrees Celsius.
After warming up, insert the plastic mediator into the corner between the frame and the glass. Move the tool along the perimeter, cutting the glue. Don't try to force the lid; if it doesn't move away, add more heat. Inside the case, you'll see a metal protective plate covering the main board and the battery.
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If you don’t have a professional heating pad, you can use a tight, sealed hot water bag (about 70-80°C) and apply it to the back cover for 10-15 minutes, a safer method for glass than a hair dryer.
To remove the metal plate, you need a Torx T5 screwdriver. There can be many screws and they can be of different lengths. Record or photograph the location of each screw, as screwing a long screw into a short hole can penetrate the motherboard right through.
- 📱 Disconnect the battery plume from the motherboard immediately after removing the protection.
- 🔌 Carefully disconnect the plumes of the display and touch screen, putting the connectors on the nail or plastic spatula.
- 🧩 Remove the main and front camera module if they interfere with battery access.
- 🔋 Remove the vibrator and speaker if the design requires their dismantling to access the battery.
Dismantling of the old battery
In the Xiaomi Mi 8 Lite, the battery is located in a niche and also fixed with a glue layer, often using special stretching tapes. Trying to simply pick out the battery with a screwdriver is strictly prohibited, as this can lead to puncture and ignition of the electrolyte.
To safely extract, use the reheating method. Heat the area around the battery with a hairdryer, but try not to heat the battery directly, as high temperatures are harmful to lithium-polymer chemistry. After heating, try inserting a thin plastic map or fishing line under the battery and sawing movements to separate it from the frame.
If the battery is swelling, be very careful, because the swelling indicates a buildup of gases inside the housing, and any mechanical damage to the shell can cause a chemical reaction, in such cases, it is recommended to additionally lock the battery with tape around the perimeter before removal to prevent deformation.
⚠️ 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 or place it in a container of water!
Once the old battery is removed, you need to thoroughly clean the seat of glue residues. Use isopropyl alcohol and a plastic blade. The surface should be perfectly smooth and clean so that the new battery will fall tight and without distortion. The presence of old glue lumps can lead to uneven pressure distribution.
| Parameter | Old Battery (Original) | New battery (Quality copy) | Cheap analogue |
|---|---|---|---|
| Capacity | 3120 mAh | 3000-3100 mAh | 2000-2500 mAh |
| Tension. | 3.85 In | 3.85 In | 3.7-3.8 Included |
| Cycle resource | 500+ cycles | 300-400 cycles | 100-150 cycles |
| Protection | Complete (BMS) | Basic | Absent. |
Installation of a new battery and assembly
The new battery for the Mi 8 Lite often comes with double-sided tape already applied.If there is no adhesive base, use special adhesive tapes for electronics or a thin layer of B-7000 glue. Never use superglue (cyanacrylate) as it becomes brittle when vibrating and can damage the insides on the next repair.
Put the battery in the niche, making sure the connector is correctly positioned. Connect the plume to the motherboard before the characteristic click. Make sure the plume is flat, without clatters. Before final assembly, it makes sense to perform a primary calibration by turning on the phone and checking the response of the touchscreen and images.
The assembly is reversed, all the components that cover the battery (vibromotor, speaker) are installed first, then a metal protective plate is screwed, and the screws are twisted cross-over, without undue effort, so as not to break the thread in the plastic racks of the case.
☑️ Checklist before closing the lid
The back cover before installation also needs to be dust-cleaned and degreased. Apply a thin layer of new glue or use a ready-made adhesive frame. Press the lid around the perimeter and lock the smartphone with rubber bands or in a special press for 15-20 minutes to polymerize the glue.
Primary start and calibration
After assembly, take your time to use the phone actively. The initial launch may take longer than usual, because the system needs to identify the new power controller. If the phone is turned on, check the charge level. Often the indicator shows 1%, even if the battery is partially charged.
To properly operate the energy management system (BMS), it is recommended to conduct a calibration cycle: completely discharge the phone before turning off, then charge it when off to 100%. After reaching 100%, hold on charging for another hour, which will help the system to correctly calibrate the percentages.
During operation, monitor the heating temperature. In the first charging cycles, the Xiaomi Mi 8 Lite can warm slightly stronger than usual - this is normal for "rocking" chemistry. However, if the heating becomes critical or the smell of burning appears, the procedure should be stopped immediately.
- 🔋 Discharge the device to 0% (spontaneous shutdown).
- 🔌 Charge to 100% in the off state.
- ⏳ Keep on charging for another 60 minutes after full filling.
- 📱 Turn on your phone and check the stability of the work.
⚠️ Warning: Do not leave your phone unattended during the first cycle after replacement, if the battery is not connected correctly or if the battery is broken, this can cause a fire.
Possible problems and solutions
Even with a careful assembly, there can be unexpected situations, and users often find that the phone does not see charging or does not turn on. Most of the time, the problem lies in a poorly latched battery connector or oxidized contacts that need to be wiped with alcohol.
Another common problem is that the fingerprint or camera doesn't work after assembly, which means you forgot to plug in the corresponding plumes or damaged them during installation. In the Mi 8 Lite, the plumes are very thin, and reconnecting may not help if the tracks are interrupted.
If the phone turns on but quickly discharges and warms up, you may have a defective battery or the power controller on the board has failed, it is also worth checking the software version; sometimes old firmware does not work properly with new batteries, and you need to update the system.
What to do if a new battery is blown?
If the screen starts peeling off the body, check if you forgot to remove the old glue or if you applied a too thick layer of new glue, and the cause may be swelling of the battery itself, which indicates its poor quality.
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The quality of the spare part determines 80% of the success of the repair.The battery savings for the Mi 8 Lite almost always result in a re-disassembly after 2-3 months.