Owning a Xiaomi Redmi 3S smartphone is often accompanied by a question about battery life, especially if the device is several years old. Initially, this device was positioned as a budget “king of autonomy”, but over time, any lithium-ion current source loses its properties. The degradation of chemical composition inside the cell is a natural process that can not be stopped, but can be delayed by proper operation or corrected by replacement.
Users often wonder what type of battery is installed inside and can it be improved? The standard capacity for this model is 4100 mAh, but the market is full of overpriced offers. It is important to understand that the real capacity rarely exceeds the factory 4100 mAh without changing the physical dimensions of the case. Attempts to cram more energy into the same volume often lead to the use of substandard cells that swell or die quickly.
If your phone starts to run out in half a day or shut down 20-30% of its charge, it is a direct signal to action. Ignoring the problem can cause the ballooning battery to start pressing the display or plumes, causing more serious breakdowns. In this article, we will discuss the technical specifications of the original battery, signs of needing to replace and a detailed algorithm for actions.
Technical characteristics of the full-time battery
The original power cell for the Xiaomi Redmi 3S (model BN41) is designed with the energy-efficient Snapdragon 430 processor in mind. The company's engineers have balanced the thickness of the case with the capacity to achieve impressive results in survival tests. The nominal voltage is 3.85 volts, and a full charge of up to 4.4 volts ensures stable operation of the system.
The battery is structurally built with Li-Po technology, which makes it thinner and lighter than classic Li-Ion analogues. But the polymer has its own peculiarities: it fears deep discharge below a critical threshold and is sensitive to overheating. The charge controller, located on the battery board itself, protects the device from voltage surges, but not from physical wear.
Here are the basic parameters to know when looking for a replacement:
- 🔋 Model: BN41 (primary identifier for search).
- ⚡ Capacity: 4100 mAh (typical) / 4050 mAh (minimum guaranteed).
- 📏 Dimensions: strictly correspond to the internal compartment of Redmi 3S/3S Prime.
- 🔌 Connector: the plume must exactly match the connector on the motherboard.
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When buying a new battery, pay attention not only to the capacity, but also to the date of production. Storing lithium batteries for more than 6 months without recharging leads to irreversible loss of capacity.
Signs of wear and the need for replacement
Not only is battery life exhausted, but it's also indirect. Software failures in the percentage of charge often confuse users to think about software problems. But if calibration through an engineering menu or third-party utilities doesn't help, the problem lies in the physical wear of the cells.
One of the most dangerous symptoms is the bloating of the battery body, which is caused by the release of gases from chemical reactions inside the sealed shell, and if the back of the phone starts to move or the screen goes "wave", it is strictly forbidden to operate the device, and the pressure inside can damage the display matrix or tear off the plumes.
It is also worth paying attention to the behavior of the smartphone when loaded:
- 📉 Sharp charge jumps: With 40%, the phone instantly turns off or shows 5%.
- 🌡️ Excessive heating of the rear panel in the battery area even under light load.
- 🔌 Phone's charging up to 100% post 30-40 minutes, but discharges in 2-3 hour.
- 💥 Spontaneous reboots when you start a “heavy” application or camera.
Replacement Battery Selection: Original or Copy?
The mobile parts market is oversupplied, and it becomes more difficult to choose a quality product. For the Redmi 3S, there are three main categories of batteries: original (OEM), high-quality copies (High Copy), and outright cheap marriage. Understanding the difference between them will save your money and nerves.
Original batteries are marked with the Xiaomi logo and have a hologram with the QR-The code for authentication on the official website, which uses high-quality, densely filled cells inside the housing, often weighs less, which indicates less active substance, and their actual capacity may be as small as the actual capacity. 2000-2500 mAch instead of the declared 4100 mic.
The comparison table will help to orient in the choice:
| Parameter | Original (OEM) | Quality copy | Cheap analogue |
|---|---|---|---|
| Real capacity | 4000-4100 mic | 3000-3500 mAh | 1500-2000 mAh |
| Cycle resource | 500+ cycles | 200-300 cycles | 50-100 cycles |
| PCB protection | Complete. | Basic | Absent. |
| Price. | Tall. | Medium | Low. |
When buying, be sure to check the quality of the contacts soldered on the plume. In cheap versions, the wires are often thin and can oxidize, leading to loss of contact and chaotic phone switches/offs. The battery board power controller should also have clear labeling, rather than being flooded with a compound without labels.
The myth of high capacity
Tools and preparation for replacement
The process of replacing the battery in Xiaomi Redmi 3S requires accuracy and a minimum set of tools. The design of the phone involves a non-shatterable case, fastened screws and plastic latches. Incorrect opening can lead to chipped frames or damage to the plumes.
Before you start, you need to turn off the device completely. If the battery is swollen and prevents the back cover from fitting tightly, be especially careful when unplugning the cover so that the fingerprint scanner plume or speaker does not damage. You will need specific tools to work, which are not always in the home drawer.
Basic repair kit:
- 🔧 Phillips screwdriver #00 (cross) for the screws of the body.
- 🔧 Torx screwdriver T5 (star) for certain modifications of screws.
- 🎴 Plastic card or mediator for snapping latches.
- 🌬️ Dryer or heating pad (to soften the glue under the cover).
- 🧲 Magnetic mat for sorting screws of different sizes.
☑️ Preparation of the workplace
It is important to prepare the workplace: the surface should be clean, light and not conduct current. Static electricity can damage sensitive electronics, so it is recommended to periodically touch the grounded metal object. If you do not have experience, it is recommended to watch the video instructions for disassembling your revision of the board, as the location of the components may vary slightly.
Step-by-step instructions for replacing the battery
Start by removing the back cover. Unlike modern smartphones, the Redmi 3S has a removable lid, but it's held on tight latches around the perimeter. Carefully tuck the angle of the lid with your nail or a plastic blade and swipe along the edges, hearing the characteristic clicks of the undocking fixers. Don't use metal knives, they can crack plastic or damage antennas.
Once the lid is removed, you can access the insides, and the first thing you need to do is to unscrew all the visible screws that attach the plastic frame to the main body, and they can range from 10 to 12. Notice the length of the screws, some of them can be longer than others, and if you confuse them when you build them, you can punch through the motherboard.
⚠️ Warning: Before turning off the plumes, make sure the phone is off.Unconnecting the connectors under voltage can cause the power controller to short-circuit and fail on the board.
The most important step is to remove the old battery, which is glued to the body with double-sided tape, which you can't pull hard, which can damage the shell and cause fire, use a hair dryer to warm up the battery area slightly (don't overheat!), and gently tweak it with a plastic card, gradually separating it from the body. If the battery is too swelled, act with utmost care not to puncture it.
Install the new element in reverse order. Be sure to degrease the planting site with alcohol and apply a new layer of glue or bilateral tape so that the battery does not hang inside. Connect the plume to a characteristic click, make sure that it sits evenly, and only then check the device on.
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The main challenge of replacing is to carefully separate the swelling battery without damaging the surrounding components, and heating and slow separation are key to success.
First start and calibration of the new battery
After a successful physical replacement and assembly, there comes a moment of truth, the first run, and if the phone is on and showing charging, you've done it right, but the Android system may not be able to properly display the charge level, because the controller remembers the parameters of an old, worn-out battery.
To work properly, it is recommended to conduct a calibration procedure. It is not strictly mandatory for modern versions of MIUI, but helps to remove percentage jumps. The essence of the method is a full charge-discharge cycle: discharge the phone until completely turned off (0%), then charge it when off to 100%, hold another hour and turn it on.
In the process of operating a new battery, the rules of “run-in” should be observed:
- 🔋 First-time 3-5 Try not to drain the phone below. 15-20%.
- 🌡️ Avoid using your smartphone while charging in the first few days.
- 📱 Turn off the extra functions (GPS, Bluetooth, until you are sure of the stability of the work.
⚠️ Warning: If after the replacement the phone warms in the lower end (where the charging connector is) even in the simple, it may have been damaged bottom plume or incorrectly installed connector.
It's also worth checking the fingerprint scanner and vibrator, because if you build them in a sloppy way, you can damage their plumes. If all the functions are working properly and the operating time is good, the replacement can be considered a success. Now your Redmi 3S is ready to give you long battery life again.