Xiaomi Redmi Note 4 has earned a reputation as a “people’s” device due to its reliability and autonomy, but over time, even the highest quality lithium-polymer battery loses capacity. If your device stops holding charge, turns off 20-30% or swells up, lifting the back cover, then it’s time to replace the battery. Self-replacement battery is real if you follow the accuracy and have a minimum set of tools.
The process of restoring autonomy requires care, because the internal layout of the smartphone is quite dense. Wrong actions can damage the plumes or the newest battery. In this article, we will look at each step in detail, from the preparation of the workplace to the final calibration of the system.
It is important to understand that before starting work, you need to make sure that the new battery is compatible with your smartphone modification, as there are versions for the global market and the Chinese version, which may differ constructively, and you should prepare all the necessary tools in advance so that you do not interrupt the process of finding a screwdriver or a mediator.
Tools and workplace preparation required
To successfully perform the procedure, you will need a specialized tool that will ensure safe dismantling of components. Use of inappropriate items such as knives or needles is strongly discouraged, as there is a high risk of damage to the polymer battery case or break the display.
- 🔧 Precision screwdrivers (Cross Phillips #000 and flat).
- 🛠 Plastic mediators or old plastic cards for clips snapping.
- 🔥 A hair dryer or thermophene for softening the glue (temperature not higher than the temperature) 80-90 degree).
- 🧲 Magnetic mat or screw sorting container.
- 🧤 Antistatic gloves and suction cup to lift the lid.
The workplace must be well lit and devoid of unnecessary items that can get lost. Small screws have the ability to "run away" and get lost in the pile of the carpet or the slots of the table, which can be fatal to complete the assembly. Organize the space in advance so that all the parts fall under your hand.
⚠️ Warning: Before starting any work, be sure to turn off your smartphone. Working with electronics under voltage can lead to short circuit and failure of the motherboard.
Dismantling of the back cover and protective screen
The first step will be the removal of the back cover, which is in the model Redmi Note. 4 It's attached to adhesives and plastic latches, and heat the perimeter with a hairdryer, evenly spreading the heat over the course of the device. 2-3 Do not hold the hair dryer in one spot for too long so as not to overheat. LCD-display.
After warming up, gently insert the suction cup into the bottom of the lid and pull up slightly to create a gap. Insert a plastic mediator into the resulting gap and guide it along the perimeter, carefully snapping the clips. The movements should be sliding, without sharp jerks, so as not to break the plastic fixtures.
Once the lid is removed, you'll see a metal shield covering the motherboard and the plumes, which is mounted with multiple screws of different sizes, and it's recommended that you take a picture of the screws before you remove them, because they can vary in length, and mix them up, and you risk breaking the board when you build them.
Nuances of the glue layer
Disconnecting plumes and removing the old battery
Once the metal shield is removed, the main components are accessed, and the first thing you need to do is to disconnect the battery plume from the motherboard, and you need to do this carefully by putting a plastic blade on the connector, not a metal blade, so that the contacts are not damaged.
The battery in this model is also placed on double-sided tape. To extract it, you can use a special hood with suction cups or gently tamper with a plastic tool on the bottom. In no case do not try to pull the battery on the top edge or plume - this can cause it to rupture or damage the controller.
If the battery is swelling, be very careful. A puncture or severe deformation of the lithium cell can cause ignition. Remove the battery as carefully as possible, trying not to damage the shell. If the battery is very strong, you can warm the area under it with a hairdryer a little, but with great care.
☑️ Pre-installing check
Installation of a new battery and assembly of the device
The new battery should be checked with a multimeter before installation. Normal voltage should be in the range of 3.7 to 4.2 Volts. If the figures are much lower, it is possible that the battery has been in storage for a long time and requires preliminary “pumping”, although modern controllers often cope with this on their own.
Apply a new layer of glue or use pre-made adhesive tapes (B-7000 or analogues) on the frame of the case. Press the battery tightly, making sure the connector is located exactly above the contact group on the board. Carefully snap the plume until a characteristic, barely audible click.
Then the assembly process goes in reverse: install a metal screen, twist the screws, put on the back cover and warm it up to fix the glue, make sure that all the screws are twisted, but not pulled, so as not to break the thread in the plastic pillars of the case.
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Use the B-7000 glue to fix the lid – it is elastic, holds well and allows you to reopen the device without heating if necessary.
Initial start and calibration of the system
After assembly, take your time to turn on the phone. Connect the original charger and leave the smartphone to charge off for at least 1-2 hours, which is necessary to activate the chemical processes in the new battery and initially calibrate the charge controller.
Once the system is turned on, you may need to fully calibrate the battery to correctly display percentages. To do this, completely discharge the phone before automatically turning off, then charge it to 100% when off. Repeat this cycle 2-3 times so that the MIUI controller reads the capacity correctly.
In some cases, after a battery change, the system may show an incorrect percentage of charge or a message that the battery is not original. This is normal for high-quality third-party batteries. The message usually disappears after several charge-discharge cycles or resetting battery statistics.
| Parameter | Norma. | Deviation | Action. |
|---|---|---|---|
| Tension (calm) | 3.7. to 4.2 B | Below 3.5 B | Low-power charging |
| Charging temperature | 30 - 40 °C | Above 45°C | Stop the charge, check the controller |
| Time to work. | 1.5 - 2 days | Less than 10 hours. | Background process verification |
| Percentage after discharge | 100% | Ride (99-100%) | Conduct 3 complete cycles |
⚠️ Warning: If the phone warms up in the camera or processor area when it is down, turn it off immediately.This may indicate poor plume contact or a defect in the battery itself.
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The quality of the new battery directly affects the stability of the processor; cheap analogues can cause voltage drawdowns under load.
Frequent problems after replacement and how to solve them
Sometimes users find that the phone does not see the new battery or does not charge, the first thing is to re-disassemble the device and check the density of the connector, often the problem lies in the oxidation of the contacts or the displacement of the plume during assembly.
Another common problem is long charging or fast discharge, which can be due not only to battery quality, but also to software failures: Try resetting to factory settings (pre-saving data) or reflashing the device through the Mi Flash Tool.
If the smartphone is powered only from the charger and immediately switches off when it is turned off, most likely, the power controller on the board is faulty or the new battery is completely discharged “to zero” and requires a “push” with a special power supply to start a chemical reaction.