Xiaomi Mi Max series smartphones were famous for their huge screens and impressive batteries, but time spares lithium-polymer batteries. When the device begins to quickly discharge, turn off at 20% charge or swell, the only effective solution is a physical replacement of the energy source. Self-repair saves a significant amount and extends the life of the gadget for several more years of active use.
The process of replacing the battery in Xiaomi Mi Max requires care, firm hand and compliance with safety. Unlike modern models with fixed covers, here the design is more predictable, but has its own nuances associated with the dimensions of the device. Before starting work, you need to clearly understand the risks associated with damage to plumes or overheating of components.
In this article, we will take a look at each step of the procedure, from the preparation of the workplace to the final calibration of the new battery, you will learn what tools are really needed, how to safely unstick the display module and what to look for when choosing the original battery BM47 or BM51 depending on the specific modification of your smartphone.
Diagnosis of the battery status and the choice of a new battery
Before you start disassembling, you should make sure that the problem lies in the physical wear of the chemical element, not in the software failure. If the phone holds a charge for a long time, but shows interest in a jump, you may need to reset the statistics or flash the firmware. However, bloating or instantaneous shutdown in the cold are sure signs that the resource is exhausted.
When choosing a new battery, it is critical to consider the model of your device: the Mi Max series came in three main versions, and the batteries are not always interchangeable due to different capacities and dimensions. The first model is characterized by a capacity of 4850 mAh, while the Mi Max 2 and Mi Max 3 received even more powerful solutions.
- 🔋 Original vs Copy: Avoid cheap counterparts without the Xiaomi logo, as their real capacity is often the same. 50-60% The term of service is calculated by months.
- 🔌 Connection connector: Visually compare the plume and connector of the new battery with the old one – they should match perfectly, without the need to bend contacts.
When buying a battery, pay attention to the date of production. Lithium polymer cells degrade even when stored in a warehouse, so a fresh release date is an important quality criterion. Try not to buy batteries that have been in storage for more than two years.
Tools and workplace preparation required
A high-quality repair is impossible without the proper tools. Attempting to open the case with a knife or credit card often leads to frame damage or injuries. To work with the Xiaomi Mi Max, you will need a specialized kit that can be purchased from any radio parts store.
⚠️ Warning: Before starting any work, be sure to completely turn off the smartphone. Attempting to replace the battery when turned on can lead to a short circuit and failure of the power controller.
Organize the workplace so that all the parts are at hand, and the lighting allows you to distinguish between small screws. A lost cog or a dropped plume can turn a simple repair into a long procedure for finding parts. Use a magnetic mat or a container with cells to sort the fastener.
☑️ Preparation for repairs
Here is a list of tools that you can not do without:
- 🧲 Mediators and sucker: Thin plastic blades will help to divide the body without scratches, and the suction cup will create the necessary gap.
The process of disassembling the body Xiaomi Mi Max
Xiaomi Mi Max is designed to allow the insides to be accessed by removing the display module, which means that the first step is to heat the perimeter of the screen. Be careful: excessive heating can damage the matrix or lead to yellow spots.
Heat the edges of the device evenly for 2-3 minutes to a comfortable touch temperature (about 80-90 degrees). After that, carefully install the suction cup at the bottom of the screen, slightly pull upwards, creating a gap, and insert a plastic mediator into it. Lead the mediator around the perimeter, cutting the adhesive layer.
Once the module is detached from the frame, don't try to pull it out of the box. It's connected to the motherboard with a few plumes. Carefully lift the screen, find a metal shield covering the connectors, and unscrew it, and then you can disconnect the display and touchscreen plumes.
💡
Warm up the case in stages: if the glue in one corner does not lend itself, warm up this area again, without increasing the overall heating temperature, so as not to overheat the battery.
Once the plumes are turned off, you can put the module down to a safe place with a screen down on the soft fabric, and you can now access the metal screen that covers the main components and the battery itself, and in some versions the battery is closed with a separate metal plate, which will also need to be dismantled.
Dismantling the old battery and installing a new one
In Xiaomi Mi Max, the battery is glued to the body with double-sided tape, which must be removed with extreme care so as not to damage the polymer battery pack, which can lead to fire.
First, disconnect the battery connector from the motherboard. Then, if you have any battery-locking screws, unscrew them. To extract the battery itself, the best way to do that is to use a thin plastic card or a special tape with adhesive layers that you can wind up under the battery.
| Parameter | Mi Max 1 | Mi Max 2 | Mi Max 3 |
|---|---|---|---|
| Model AKB | BM47 | BN43 | BM4E |
| Capacity | 4850 mAh | 5,300 mAh | 5,500 mAh |
| Type | Li-Po | Li-Po | Li-Po |
| Difficulty replacing | Medium | Medium | High (two-section) |
Clean the seat in the case of residues of old glue and contaminants. Degrease the surface with alcohol or a special cleaner. Apply a new layer of glue or bilateral tape (often complete with a new battery) around the perimeter and in the center for reliable fixation.
Install the new battery, making sure it lies flat and doesn't bulge. Connect the connector to the characteristic click. Before the final assembly, it makes sense to briefly turn on the phone to check if the charge is going on and if the device is being detected.
What to do if the battery is not glued?
Assembly of the device and check of performance
The reverse order is done, first of all, reconnect the display plumes and touchscreen, then install a metal plate and twist the screws. It's important not to pull the screws so as not to break the thread in the plastic seats.
Before you finally glue the screen, turn on the phone and check the basic functions: sensor operation, sound, vibration and charging. Make sure that the image on the screen is smooth, without artifacts that may have appeared due to the loose connection of the plume.
⚠️ Warning: If the smartphone doesn't turn on after assembly, don't rush to disassemble it again. Try putting it on charge at the end of the day. 15-20 A deep-discharged new battery could have gone into defense.
If all tests are successful, apply a new adhesive around the frame (or use the original adhesive tape). Press the screen tightly against the body and lock the device with rubber rings or a load for 1-2 hours before the glue is fully grasped.
Calibration and operating recommendations
After the battery is replaced, the system may not display the charge level correctly, since the memory controller has not updated. To calibrate the new Xiaomi Mi Max battery, it is recommended to perform a full charge-discharge cycle, which will help the system correctly determine the real capacity.
Discharge the phone until it's completely turned off (0%). Then set it to charge when it's off to 100%. After reaching full charge, hold it on charging for another hour. Then turn on the phone and, if the indicator is not 100%, re-connect the charger. Repeat the procedure 1-2 times.
To extend the life of a new battery, try to avoid deep discharge to zero and keep the phone on charge all the time. The optimal range of lithium polymer batteries is from 20% to 80%. Also avoid overheating the device during games or charging.
💡
Proper calibration in the first days of use allows the system to accurately display the percentage of charge and extends the overall life of the new battery.