Xiaomi Redmi 4A has earned the status of a popular device due to its excellent price-performance ratio, but over time, even the most reliable lithium-ion power source loses its capacity. If your phone starts to quickly discharge, turn off 20-30% of charge or the body is swollen, then it's time to think about replacing the battery. Self-replacement is not only a way to save on services of the service center, but also the opportunity to personally monitor the quality of installed components.
The process of opening a monoblock case requires care, because the back cover is glue-based and the internal plumes are very fragile. In this article, we will discuss in detail all the steps of work, from the preparation of the workplace to the final calibration of the new battery, careful adherence to the sequence of actions will help to avoid damage to the display or motherboard.
Before you start disassembling, you need to make sure that the problem is that it's the wear of the battery, not software failures or a faulty charge controller. Often users confuse a software bug with the physical degradation of the cell chemistry. However, if the device is several years old, the probability of physical wear is more than 80%. Let's get ready for the procedure.
Diagnostics and tool preparation
The first step is visual inspection and software diagnostics. Battery bloating is a clear signal to be replaced immediately, as further operation can damage the display or even fire. Software checks can be done using built-in system tools or third-party utilities, but a physical examination after opening will give 100% of the result.
To make a quality replacement, you will need a minimum set of tools that can be purchased from any electronics store or ordered online. Do not use sharp metal objects like knives to tamper with the case, as there is a high risk of damaging the plastic or piercing the battery itself.
- 🔧 Set of screwdrivers: mandatory presence of a cross screwdriver PH00 or PH000 charge-pen.
- 🛠 Plastic spatula (mediator): necessary for safe slashing of the lid without scratches.
- 🌡 Dryer or heating platform: to soften the glue under the back panel (temperature near the back panel) 80-90 degree).
- 🧲 Magnetic mat or organizer: to avoid losing tiny screws of different sizes.
It is also important to prepare a workspace with good lighting. Small parts, such as plume connectors, are not easily distinguishable in dim light. If you do not have experience with small electronics, it is recommended to watch video disassemblies of similar models in advance to understand the overall architecture of the device.
⚠️ Warning: Before starting any work, be sure to completely turn off the smartphone. Attempting to disconnect the battery plume when the device is turned on can lead to a short circuit and failure of the power controller on the motherboard.
Make sure the charge is less than 25% but not less than 5%. Fully discharged lithium batteries are sometimes difficult to start without special equipment, and fully charged batteries carry an increased risk of damage. The optimal charge level for starting work is about 15-20%.
Rear cover removal process
The most difficult step for the inexperienced user is to carefully remove the back panel. In the Redmi 4A, it is glued around the perimeter, and manufacturers use a sufficiently persistent adhesive composition to ensure the construction is monolithic, and rush is unacceptable here.
Heat the edges of the body around the perimeter with a hairdryer for 2-3 minutes. Do not hold the hairdryer at one point for too long so as not to overheat the display matrix on the back. The plastic should become warm to the touch, indicating softening of the glue. After that, insert the plastic card or mediator into the junction between the frame and the cover.
What to do if the lid is cracked?
Move the blade along the perimeter, gradually snapping the plastic latches. You'll hear the characteristic clicks. Pay special attention to the areas around the camera and the speaker, where the glue often holds tighter. Don't try to remove the lid with a jerk, move progressively.
- 🔥 Heat the body evenly from all sides, giving more time to the corners.
- 📱 Insert the suction cup (if any) in the lower part to create an initial gap.
- 🚫 Avoid using metal blades that can damage the plumes under the lid.
Once the lid is removed, you will have access to the internal layout. In Xiaomi Redmi 4A architecture is dense, but logical. Immediately pay attention to the location of the plume of the display and the battery connector, so that you do not accidentally hit them with a tool.
Replacement of the battery and disconnection of plumes
Inside the case, the battery is central and often additionally fixed with adhesive strips or plastic tongues. In this model, the battery can be glued to a middle frame or plastic base. To extract, you will need to apply heating again, but already directed to the inside of the case.
The first thing you do is to disconnect the battery plume from the motherboard, which is under a metal screen or a plastic pad that's pinned down by the screws, carefully unscrew the screws, remove the pad, and disconnect the connector by putting a plastic blade up from the bottom.
☑️ Checklist before installing a new battery
Use a plastic card to extract the old battery, gently sticking it under the battery. If it sits very tightly, you can use a special glue solvent or isopropyl alcohol by putting a couple of drops under the edge of the battery and waiting a couple of minutes. Never try to pull the battery behind the wires or puncture its body.
The new battery should be installed in strict accordance with the orientation of the old one. Pay attention to the location of the contact group. After installation, press the battery tightly over the entire area for good heat sink and fixation. Connect the plume to the characteristic click.
Assembly of the device and check of performance
Before you finally seal the case, you need to do an initial check. Turn on your smartphone by pressing the power button. If the screen catches fire and the device starts to load, that's a great sign. Check if the percentage of charge is displayed and if the charging process is going on when you connect the cable.
Make sure all the screws are back in place. Redmi 4A uses screws of different lengths, and if you mix them up, you can damage the board or not get into the thread. Usually, longer screws go to corners or to the mounting places of heavy modules.
Apply a new layer of glue (B-7000 or analog) to the frame of the body in a thin strip. Let the glue dry slightly (1-2 minutes), then gently press the back cover. Lock the device with rubber bands or a load for 15-20 minutes before the initial grip.
| Parameter | Standard value | Permissible deviation |
|---|---|---|
| Battery capacity | 3120 mAh | ± 50 mAh |
| Nominal voltage | 3.85 In | 3.80 - 3.90 |
| Heating temperature at charge | 35-40 °C | 45°C |
| Time to dry glue | 24 hours. | polymerization |
After assembly, run a stress test: run a heavy app or game for 10-15 minutes. The phone should not turn off spontaneously, and the temperature in the battery area should not exceed comfortable values. If everything is successful, the replacement can be considered complete.
Calibration of the new battery
Once a new battery is installed, the charge controller may not display the charge level correctly because it "remembers" the parameters of the old battery that has worn out. For the system to correctly assess capacity, a calibration procedure is necessary, which is especially important for MIUI-based devices.
Discharge the phone until it's completely turned off. Then charge it when it's off and wait until the indicator shows 100%. Then don't take the charger off for another 1-2 hours, so the controller can lock in the upper charge limit.
Then turn on the phone (without turning off the charge) and check if the percentage has dropped. If it has dropped, charge it back to 100%. Repeat the cycle until the percentage is stable at 100% when you turn on the charger, and then you can use the phone as normal until it is completely discharged.
⚠️ Note: Do not use third-party battery "calibration" applications that require Root-rights. Mechanical calibration in charge-discharge cycles is the safest and most effective method for modern lithium-polymer batteries.
The calibration process can take a day or two, but it's worth it. A properly calibrated battery will last longer, because the power controller will correctly control the charge and discharge currents, preventing deep discharges.
Frequent mistakes and tips for extending the service life
Many users make mistakes that negate the replacement result, such as using cheap battery analogues without protection or ignoring the temperature regime. Original parts or quality counterparts from proven brands (Nohon, Cameron Sino) last 2-3 times longer than unnamed Chinese copies.
Try not to get your phone to a deep discharge state (0%) regularly. Lithium chemistry degrades faster at extreme charge values. The optimal range for everyday use is between 20% and 80-90%.
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Use Xiaomi's original charger or certified Quick Charge-enabled counterparts. Cheap power supplies often give unstable voltage, which kills the battery controller in a matter of months.
Avoid overheating, too. Don't leave your phone in the sun, on a car torpedo, or under a pillow while charging. High temperatures are the main enemy of lithium batteries, and they irreversibly reduce their capacity.
- 🔋 Do not keep your phone with a fully discharged battery for a long time.
- 🌡 Avoid using your phone while charging intensively (games, navigation).
- 📱 Remove a thick case during fast charging for better heat sink.
Compliance with these simple rules will allow you to forget about the problem of fast discharge for a long time. Xiaomi Redmi 4A with a new battery will again enjoy autonomy comparable to new budget models.
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The quality of a battery replacement depends on the accuracy of the execution and on the quality of the battery by 50%. Don't skimp on components.