Redmi 4 series smartphones have earned a reputation for being "unkillable" devices, but even the most reliable lithium polymer battery loses its capacity over time. When the phone starts to run out in a couple of hours or suddenly turns off at 20% charge, the only effective solution is a physical replacement of the battery, which requires care, because the internal layout of Xiaomi involves a dense fit of components.
Before disassembling, you need to be aware of the risks of damage to a lithium polymer battery. Mistakes can lead not only to failure of the device, but also to fire. In this article, we will discuss in detail the process of dismantling an old battery and installing a new one, paying special attention to the nuances of working with adhesives and fragile plumes.
The success of the operation depends on the quality of the workplace and the availability of a specialized tool. You should not try to replace the battery "on the knee" or using improvised tools like knives, as this increases the likelihood of damage to the display or puncture of the cell itself.
Diagnostics and workplace preparation
The first step is to accurately diagnose the condition of the device. Often users confuse software failures calibration of the power controller with the physical degradation of the cell. If after resetting and checking in Settings → About phone → Statistics persists, and the phone is swelling or warming, a replacement is inevitable. Before starting work, the device must be completely turned off, holding the power button until vibration.
The organization of the workspace is critical. You'll need a table with good lighting and antistatic coating if possible. Small screws are easily lost, so prepare a magnetic mat or a container with cells to sort the fastener through the dismantling stages, which will avoid the situation when there are "extra" parts after assembly.
⚠️ Warning: It is strictly forbidden to start disassembly if the charge level of the phone exceeds 25%. Damage to the battery with a high charge can cause instant thermal destruction and the release of toxic gases.
The job will require a specific set of tools that are essential for safe operation, and the use of office knives or screwdrivers of the wrong size will cause plastic chipping and damage to internal cables.
- 🔧 Precision screwdrivers (cross-haired) PH000 flat)
- 🎴 Plastic blades and mediators for opening the body
- 🌡️ Hair dryer or heating platform for softening glue
- 🧲 Magnetic matrix for screws
- 💧 Isopropyl alcohol or special liquid B-7000
It's important to make sure that all tools are in good working order, that the screwdriver stinger doesn't have to be licked, that the plastic blades don't have to have sharp, intact edges, and that you put extra effort into using a blunted tool, which increases the risk of slipping and damage to the motherboard.
Metal shell opening process
Xiaomi Redmi 4 (Prima) has a metallic non-antenna body that imposes its own features on the opening procedure. Unlike plastic counterparts, you can't just plug the back cover. The main mount is a perimeter adhesive layer that needs to be preheated. Uniform heating to 80-90 degrees Celsius makes the glue plastic and allows you to open the smartphone without deforming the frame.
Heat the device carefully, controlling the surface temperature, so as not to damage the display matrix or plastic elements of the internal structure. After warming, suction cups and thin plastic blades come into play. The suction cup is attached to the bottom of the back cover, creates a vacuum and slightly pulls up, while introducing the blade into the gap.
💡
Use a thermometer or a pyrometer to control the temperature of the heat, and if you hold the phone in your hand and it's hot, it's already too hot for the internal components, and it's optimal to heat it with a hair dryer for 2-3 minutes with breaks.
The blade movements should be sliding, parallel to the plane of the lid, not piercing up. Walk the tool around the perimeter, gradually releasing the adhesive layer. Pay special attention to the areas around the camera module and the speaker where the adhesive can be applied more abundantly. Sharp jerks can lead to cracks in the glass or deformation of thin metal.
Once the perimeter is free, don't try to remove the lid right away. There may be thin plumes inside, although in this model the main switching is protected. Carefully lift the edge and visually make sure there are no connections between the top and bottom of the case. Only then you can finally remove the metal panel.
Dismantling of protective screens and access to the battery
When you take off the back cover, you'll see a metal screen covering the bulk of the components. In Redmi 4, this screen is often screwed with many screws of different sizes. They need to be twisted counterclockwise, following the order in which they were installed so that when you build, you don't confuse the length of the thread. A longer screw in a short hole can break through the board.
Under the metal casing, there's a battery pack and plume connectors. Before you touch the battery, you need to turn off the power, and you need to carefully disconnect the plume from the main board to the daughter board (where the charging connector is located) and the battery plume. You need to use a plastic blade here, the metal can close the contacts.
☑️ Procedure for disconnecting plumes
Once you shut down all the connections, you can remove the metal plates that hold the connectors, which are usually held on one or two screws, and when you take off the protection, you have full access to the battery area, and it's important not to lose these plates, because they allow the connectors to fit tightly and protect them from vibration.
Some modifications may have additional insulation or heat pads under the screen, which must be carefully removed and laid down to a clean place, and damage to the graphite layers will lead to a deterioration in the heat sink, which is critical for the processor and power controller in the further operation of the device.
Removal of the old battery
The battery in Xiaomi Redmi 4 is attached to double-sided tape, which eventually loses its properties, but the first time it is replaced can hold very tight. Under no circumstances try to tamper with the battery with a screwdriver or a knife - a puncture of the cell will cause instant fire. The only safe method is the use of a heater and a thin line or a special hood.
You put it back on the heating platform for 3-5 minutes, and the heat will soften the adhesive layer under the battery, and then you can use a plastic card or a sticky tool to try to move the battery, and if the battery doesn't respond, repeat the heat, but don't use force.
⚠️ Warning: If the battery case is damaged, bloated or has traces of electrolyte, it should be removed with extreme caution in a non-combustible container.
There's a method that uses a thin line or a guitar string, and you put a line under the edge of the battery and you seed it along the adhesive layer, and it takes skill, but it's the safest way for the integrity of the cell and the body, and the movement has to be smooth, without jerking.
Once the old battery is removed, you need to thoroughly clean the seat of the old glue, using isopropyl alcohol and a plastic blade, the surface must be perfectly smooth and clean, so that the new battery lies flat and stays secure, and the glue residue can create air pockets that degrade the heat sink.
Installation of a new battery and assembly of the device
Before installing a new battery, check its voltage with a multimeter. 3.7-4.2 Voltage, if the voltage is lower 3.5 B, the battery is desirable to "wake up" a special charger before installation, although modern controllers BMS Often allow charging and through USB. A new layer of glue is applied to the bottom of the niche (B-7000 or special stickers).
Carefully place the new battery in the niche, combining the connector with the return part on the board. Do not plug the plume immediately! First make sure that the battery is flat, does not bulge or dangle. Only after physical fixation, you can gently snap the connector to the characteristic click.
💡
The key to building is to check the phone before all screws are finally twisted, turn the device on, make sure you react to charging and display the correct percentage of charge.
Then the assembly process goes in reverse, you put metal shields in, you screw them, you screw them, you don't have to pull the screws, especially the ones that attach the plastic, because the soft metal threads break down easily, and you twist them evenly, cross-cross.
The back cover is then reset after the new adhesive is applied around the perimeter, the old adhesive layer is removed from the lid and the frame completely, and once the lid is installed, the phone can be fixed with rubber bands for 15-20 minutes for primary glue polymerization.
Primary start and calibration
After assembly, you need to run the first run. If the phone doesn't respond to the power button, plug in the original charger for 10-15 minutes. Sometimes it takes the power controller time to "see" the new battery and start the circuit. If the phone is on, check the current charge right away.
Calibration is recommended for the charge indicator to work properly, especially if the controller remembers the parameters of an old, degraded element, and calibration will help the system correctly display percentages and work correctly with energy saving modes.
Calibration method
In the early days, watch the heating temperature of the case. The new battery may warm a little while the chemical is being formed, but the heating should not be critical.
If all parameters are normal, the device is ready for full operation, and properly performed replacement will return the Redmi 4 smartphone to factory autonomy and extend its life for several more years of active work.
Comparison of original and compatible batteries
When choosing a new battery, the user faces a variety of options, the market is full of both original components and quality counterparts and outright marriage, and understanding the difference will help avoid re-repairing in a month.
| Characteristics | Original (OEM) | Quality analogue | Cheap copy |
|---|---|---|---|
| Capacity | Complies with the stated (4100 mAh) | Often understated by 10-15% | Real capacity of 30-50% of the declared |
| Cycle resource | 500+ cycles up to 80% capacity | 300-400 cycles | Degradation through 50-100 cycles |
| BMS controller | Stable, overheating protection | Basic protection | Absent or incorrect work |
| Dimensions | Perfect landing. | Minimal deviations are possible | It can swell and push on the screen. |
Xiaomi’s original batteries are often labeled with holograms and have QR-But it's getting harder to find a truly new original for the 2016 model, and most of the offerings on the market are refurbished items or inventory residues.
High-quality products from well-known manufacturers (e.g. Nohon, Cameron Sino) are often the best choice for an older device, providing honest capacity and reliable protection, the main thing is to buy from trusted sellers, avoiding unnamed "originals" in transparent bags without packaging.
⚠️ Warning: Avoid batteries labeled "10000 mAh" or more for this model. It is physically impossible to fit such a capacity into the dimensions of a Redmi 4 using modern safe technologies.