Xiaomi Redmi Note 4, released in 2017, has become a real bestseller thanks to the combination of performance and autonomy. However, time does not spare lithium-polymer batteries, and even the most reliable device eventually begins to quickly discharge or turn off in the cold. Owners often wonder whether it is possible to replace the battery without resorting to expensive services of service centers. The answer is unequivocal: yes, it is real, but requires accuracy and understanding of the structure of the device.
The power supply replacement procedure in this model has its own nuances, which distinguish it from more modern smartphones with non-removable covers. The design of the Redmi Note 4 allows you to access the insides without completely dismantling the display, which significantly reduces the risk of damage to the matrix. However, careless movement can damage the plumes or the battery itself, so before starting work you need to carefully prepare and study the theoretical part.
In this article, we will take a look at the entire process, from tool preparation to final assembly. You will learn how to safely unplug the back cover, unplug connectors and install the new battery correctly. It is important to understand that the rated capacity of the original BM47 battery is 4100 mAh, and any deviations in the big way on cheap copies are often a marketing ploy. Following the instructions will help you prolong the life of your gadget.
Tools and workplace preparation required
Before you start dismantling, you need to organize a comfortable workplace, the ideal option is a table with good lighting and a clean surface, where small screws are not lost, and you need a special set of tools for electronic repair, which can be purchased at radio stores or online.
The main tool for uncoupling the lid is a medical heating pad or a professional heating separator. If you don't have one, you can use a household hair dryer, but with caution not to overheat the plastic. To unscrew the screws, you will need a PH00 or PH000 sized cross screwdriver, because the screws in Xiaomi are very small.
- 🔧 A set of precision screwdrivers (cross and flat)
- 🌡️ A hair dryer or heating panel to soften glue
- 💳 Plastic card or mediator for opening the case
- 🔩 Tweezers with dielectric tips
Also, be sure to prepare the screw folding container, as they can differ in length and thread. By confusing them during assembly, you can damage the case or. Using a magnetic mat will greatly simplify sorting of fasteners during operation.
☑️ Preparation for disassembly
Safety measures when working with lithium-polymer batteries
Battery management requires strict safety regulations: Lithium-polymer batteries installed in the Xiaomi Redmi Note 4 are sensitive to mechanical damage and overheating. Puncture or severe deformation of the battery can lead to ignition or even explosion.
⚠️ Warning: Never try to pierce, bend at a 90 degree angle or heat the battery above 60 degrees Celsius.This can cause an irreversible chemical reaction.
Before disassembling, be sure to discharge the device to 20-30%. A fully charged battery has maximum energy potential, and short circuiting contacts in this state is the most dangerous. If the battery is swollen, you need to work with it with extreme caution, trying not to press it with tools.
Use only plastic or wooden tools to pick around the battery. Metal objects such as needles or blades can accidentally close contacts on the board or damage the battery shell. If you smell the electrolyte or see smoke, immediately stop working and take the device out into the open space.
- 🚫 Do not use metal tools near the battery.
- 🔥 Avoid direct contact of the hair dryer with the battery
- 💧 Keep the device from getting moisture during repairs
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If the battery is too swelled and interferes with the opening of the lid, do not press it. Carefully apply the edge of the swelling with a plastic blade to create a gap, and continue to heat the glue around the perimeter.
Removal of the back cover and dismantling of components
The Redmi Note 4 has an all-metal body with plastic inserts for antennas that are glued to the frame. To remove the lid, you need to warm the perimeter of the device evenly. Heat the edges for 2-3 minutes, constantly moving the hair dryer so that the plastic does not melt and change color.
After heating, insert a plastic card or mediator into the junction between the frame and the lid at the bottom of the smartphone. Carefully guide the tool along the body, cutting through the adhesive layer. Don't try to lid the antenna inserts - they are fragile and can break. Move slowly, periodically warming the cooling areas.
When the lid is removed, you'll see a metal screen covering the insides, it's attached to a lot of screws around the perimeter and in the center. Unscrew all the visible screws using a suitable screwdriver. Some screws can be hidden under stickers or rubber plugs, carefully inspect the board.
When the metal screen is removed, you have access to the motherboard and the battery, and the first thing you need to do is to disconnect the battery plume from the board, and then you need to carefully bend the connector's locking plate (if you have one) and put a plastic blade on the connector, and then you can continue to work inside the case after the connector is turned off.
How to safely remove an old battery
In the Xiaomi Redmi Note 4, the BM47 battery is mounted on double-sided tape. Manufacturers use a glue that is aggressive enough to make it fit tightly, so you can't just pull the battery out.
There are several proven ways to extract it. The safest is to use a special suction hood, but at home, you're more likely to use a thread or plastic card method. If you use a thread (like a dental floss or a fishing line), run it under the battery and move it from side to side, cutting the adhesive layer.
⚠️ Attention: It is strictly forbidden to smack the battery with sharp objects or press on its center.
If the battery is very tight, you can carefully warm up the back of the smartphone (screen area) with a hairdryer at minimum power for 30-40 seconds. This will soften the glue under the battery. Be careful not to overheat the display matrix, which is also sensitive to high temperatures.
When you remove it, pay attention to the state of the plume that connects the bottom board to the top board, and it passes under or near the battery, and don't damage this thin conductor, because it's going to require a more complex disassembly, and if the plume gets in the way, carefully pull it aside with tweezers.
- 🧵 Use dental floss to cut glue
- 💳 Plastic card will help to undermine the edge of the battery
- 🌡️ Light heating of the back panel will facilitate the process
Installation of a new battery and assembly of the device
Before installing a new battery, you need to clean the bed of the residue of old glue. Use isopropyl alcohol or a special solvent for glue, applying it to a napkin. The surface must be clean and fat-free so that the new scotch is held securely.
The new BM47 battery needs to be pasted with strips of double-sided tape, usually with a new battery or repair kit, and don't glue the entire battery surface, just 4-6 strips around the edges and in the center to leave room for heat sink and possible expansion.
| Parameter | Original | Quality copy | Cheap analogue |
|---|---|---|---|
| Capacity | 4100mAh | 3800-4000 mAh | 2500-3000 mAh |
| Tension. | 3.85V | 3.85V | 3.7-3.8V |
| Weight. | ~90g | ~85-90g | ~60-70g |
| QR-code | Clear, readable. | Clear. | Blurred/missing |
Carefully put the battery into the case, matching the contacts with the connector on the lower board. Make sure the bottom board plume is not clamped. Press the battery around the edges to lock. Now you can connect the connector to the motherboard. You should hear a slight click, meaning that the connector has fallen into place.
How to check polarity during installation?
Before you finally spin the screws and stick the lid, it's recommended that you check the system's performance. Press the power button. If the screen catches fire and the phone starts loading, you did it right. If there's no reaction, double-check the battery connector.
Calibration and primary charging after replacement
After a new battery is successfully installed, Android may not display the charge level correctly, which is normal because the power controller must "get to know" the new battery, and calibration is required to work properly.
First, fully discharge the phone until it turns off. Then, when it's off, charge it and wait for 100% charge. Then you can turn on the device. In the first days of use, try to keep the discharge below 10-15%.
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The first 3-5 charge-discharge cycles are critical to forming the correct capacitance profile in the power controller.
If you see a quick discharge or percentage spike after replacement (for example, from 40% sharply falls to 10%), you may have a defective battery or the problem lies in the software, in which case you should check the battery consumption statistics in the Settings → Battery menu.
A quality battery replacement can bring the Redmi Note 4 back to life, making it comparable to its new autonomy, using original components and following the installation technology, ensuring that the device will work smoothly in all operating conditions.
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After assembly, check if the back cover warms up in the battery area when charging. Easy heating is acceptable, but if the phone gets hot, stop charging immediately and check the connection.