Xiaomi Redmi 4X has long been one of the most popular devices in the budget segment, largely due to its autonomy. Many owners still actively use this model, but over time face the inevitable wear of the energy element. The question of which battery is installed inside becomes critical when finding a replacement or diagnosing charging problems.
In this article, we will discuss in detail the technical characteristics of the standard battery, its marking and differences from analogues. You will learn not only the formal figures, but also the real capacity indicators, as well as practical recommendations for extending the life of the device.
The information below will help you avoid buying low-quality copies and properly assess the condition of your gadget. Understanding what is inside the case is the first step to competent maintenance of electronics.
Technical characteristics of the standard battery
The Redmi 4X’s official specs state a battery capacity of 4,100 mAh – a pretty high figure for a device released in 2017, especially given the compact 5-inch screen, and the manufacturer used a lithium-polymer (Li-Po) type of battery that has no memory effect and allows for thin enclosures.
However, the actual capacity available to the user may be slightly different from the stated capacity, due to the calibration of the controller and manufacturing tolerances, and the nominal voltage of the battery is 3.85 V, which is the standard for modern mobile devices, providing a balance between energy density and safety.
It's important to note that the battery is not removable in the classical sense, it's covered with a plastic cover, but it doesn't require heating the glass or using sophisticated tools like the flagship models, which makes it easier to maintain.
The energy efficiency of the device also depends on the Snapdragon 435 processor, which consumes little power, coupled with a capacious battery, this provided up to two days of standby, but the physical wear and tear of the chemistry reduces these performance over time regardless of software optimization.
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The declared capacity of 4100 mAh is a nominal indicator, the real life depends on the number of recharge cycles and the operating conditions of the device.
Battery model and marking
When looking for a spare part, the exact model is the parameter. For Xiaomi Redmi 4X (codenamed santoni), a battery labeled BN41 is used, which is the code you need to look for on the label when buying the original part.
Chinese manufacturers often use the same batteries for different models within the same line. The BN41 can also be found in some versions of the Redmi 4 Prime and Redmi Note 4X, but physically they can differ in the location of the plume or dimensions.
⚠️ Note: Buying a battery with labeling BN41, It is designed for other models (e.g. Redmi). 4A), This will make it impossible to install, and the plume may be displaced, and the dimensions may not match the seating position.
The original battery always has a hologram with QR-A fake is often given out by a barcode or a blurred print of text. The original battery weighs about 85-90 gram, while cheap counterparts can be significantly lighter due to the use of less dense materials.
How to verify the authenticity of QR-code?
Capacity comparison: original vs. analogues
The parts market is crowded with battery offerings for the Redmi 4X. To understand the difference, let’s compare the key parameters of the original part and common counterparts in the table below.
| Parameter | Original Xiaomi BN41 | Quality analogue (Nohon, Deji) | Cheap Chinese equivalent |
|---|---|---|---|
| Declared capacity | 4100mAh | 4000-4200 mic | Up to 5,000mAh (often lies) |
| Cell type | Li-Po (high density) | Li-Po / Li-Ion | Li-Ion (old type) |
| Cycle resource | 800+ cycles up to 80% | 500-600 cycles | 200-300 cycles |
| Controller | The original chip | Compatible chip | Simple protection fee |
It's a marketing ploy. The physical size of the cell is limited to the dimensions of the Redmi 4X. It's impossible to increase the capacity of the same volume without changing the chemical composition (for example, switching to graphene elements, which are not yet available in the mass market).
High-quality third-party brands like Nohon or Deji honestly state the capacity close to the original and provide stable voltage, while cheap copies can show 100% charge, but discharge in a couple of hours due to the use of old or defective cells.
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If you see a battery with a sign 5000 mach for Redmi 4X at a low price, the probability 99% It's a fake. The actual capacity will be around. 2500-3000 mic.
Symptoms of wear and the need for replacement
There are a number of indirect indications that the BN41 battery has run out of life: Lithium polymer batteries are degraded gradually, but there are times when replacement becomes inevitable.
Here are the main signs that the battery needs replacement:
- 📉 The smartphone turns off when charged 15-20% — This is a sign of a controller's "memory effect" or cell degradation.
- 🔋 Fast Standby Discharge – The phone loses up to 30% of its charge overnight without active action.
- 🌡️ Strong heating of the lower body during charging or simple tasks.
- 📱 Battery bloating is the most dangerous symptom requiring immediate intervention.
Bloating is caused by the release of gases inside the sealed shell. If you notice that the back cover of the Redmi 4X has begun to move away or the screen has risen on one side, immediately stop using the device.
⚠️ Warning: Do not attempt to puncture a swelling battery or mechanically impact it, which can cause electrolyte ignition and chemical burns.
If a phone that used to charge in 2.5 hours now gains full capacity in 4-5 hours (with proper cable and power supply), this is a sure sign of capacity loss.
The process of self-replacement of the battery
Replacing the battery in Xiaomi Redmi 4X is one of the easiest procedures in the world to repair smartphones. The device’s design allows you to access the battery without removing the display, which minimizes the risk of damage to the screen plumes.
To work, you will need a new battery model BN41, a cross screwdriver (usually the size of PH00), a plastic spatula (spooger) and a suction cup.
The procedure is as follows:
- Remove the back plastic cover, undercutting it with a nail or a spatula in a special recess.
- Unscrew 10 screws that fix the plastic frame covering the motherboard and battery.
- Carefully disconnect the battery plume from the connector on the board, undercoating it with a plastic spatula.
- Remove the old battery. If it's glued, use a suction cup or gently slap it with a spatula, trying not to damage the shell.
- Install a new battery, plug in the plume and assemble the device in reverse order.
☑️ Checklist before assembly
Pay special attention to connecting the plume. It should stand tight and flat. After assembly, do not close the lid immediately. Turn on the phone and check if the charge is coming, if the percentage is determined. If everything works correctly, you can twist the screws.
What if the phone doesn’t turn on after replacement?
Operating rules and calibration
After installing the new BN41 battery, it is recommended that calibration be performed, which will help the power controller to correctly determine the charge levels and avoid percentage spikes.
The calibration algorithm is simple:
- 📱 Discharge the phone until it is completely turned off (0%).
- 🔌 Put on charging in the off state to 100%.
- ⏳ After the 100% hold on to the charger. 1-2 hour.
- 🔄 Turn on your phone and use it normally.
To extend the life of a new battery, try to avoid deep discharge. Lithium polymer cells best feel in the charge range from 20% to 80%. Keeping the device constantly on charge 100% or discharge to zero accelerates the degradation of chemistry.
Also avoid overheating. Redmi 4X has a plastic body that dissipates heat worse than metal. Don't play heavy games while charging, and don't leave your phone in direct sunlight. High temperatures are the main enemy of lithium batteries.