Xiaomi Redmi Note 4 is one of the most popular models in the history of the brand due to the combination of performance and autonomy. However, even the most reliable lithium-polymer battery loses its capacity over time, and the device stops holding charge full day. If your phone runs out in a couple of hours or suddenly turns off at 20-30%, it’s probably time to replace the power source.
Self-replacement of the battery is a cost-effective way to bring the gadget back to life without going to the service center. The procedure requires care, but it is quite feasible at home with a minimum set of tools. In this article, we will discuss in detail the process of disassembling the case, disabling the plumes and installing a new part so that you can get it right the first time.
It is important to understand that any manipulation of the internal components of the smartphone carries certain risks. Wrong actions can damage the plumes, screen or even fire the battery.
Diagnostics and selection of a new battery
Before you start disassembling, make sure that the problem lies in the physical wear of the battery, not software failures or background processes. Check the usage statistics in the section Settings → Battery. If the discharge schedule looks smooth, but the phone turns off in the cold or when the load is abruptly surge, this is a sure sign of degradation of the chemical composition of the battery.
When choosing a new battery for the Redmi Note 4 (BM46 model), it is critical to pay attention to the manufacturer: the original parts are marked with the BM46 code and have a capacity of about 4100 mAh. The market is full of cheap counterparts that can swell after a month of use or incorrectly display percentages of charge.
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When buying, pay attention to the date of battery production. Lithium cells age even on the shelf, so don't take batteries that have been in storage for more than a year.
The original battery usually has a hologram and QR-Copies are often distinguished by the quality of the soldering contacts and the thickness of the case, which can lead to problems when assembling the device.
⚠️ Warning: Never use bloated batteries. Mechanical pressure on such a cell during disassembly can cause it to ignite or burn chemically.
Tools and workplace preparation required
To successfully replace, you'll need a specific set of tools, because the case of the smartphone is tightly assembled and requires delicate handling. A standard screwdriver from the school set will not be enough - you need tools to work with small electronics.
Prepare the following equipment before starting work:
- 🔧 Sets of screwdrivers (cross Philiips #00 and flat)
- 🛠 Plastic blade or mediator for opening the body
- 🌡 Hair dryer or heating platform (to soften glue)
- 🧲 Magnetic screw-sorting mat
The workplace should be well lit and free of unnecessary objects. Small cogs tend to fly around the room and get lost in the pile of the carpet, so having a magnetic mat or at least white paper will greatly facilitate the assembly process.
☑️ Preparation for repairs
It is also recommended to pre-discharge the smartphone to a level of 20-25%, which will reduce the risk of short circuit in the event of careless handling of contacts, although completely turning off the device is a prerequisite for starting work.
The process of disassembling the Redmi Note 4 body
Start dismantling by turning off the device and removing the tray for SIM-It's a standard procedure that allows you to access the screws hidden under the frame. The Redmi Note 4 uses a metal body, which makes the structure durable, but makes it difficult to access inside.
The main challenge is to remove the back cover, which is planted on double-sided tape around the perimeter. Heat the edges of the body with a hairdryer to a temperature of 60-70 degrees (hold 1-2 minutes) so that the glue softens. Don't overheat the screen, otherwise it may peel off or go yellow spots.
Heating temperature: 60-70°C
Heating time: 90-120 secondsAfter heating, insert the plastic blade into the joint between the frame and the cover in the tray area. SIM-Carefully guide the instrument around the perimeter, snapping plastic latches, the main thing is not to damage the plume of the fingerprint scanner, which is located at the bottom of the lid and connected to the motherboard.
⚠️ Warning: Do not use metal objects (knives, needles) to open the case.The metal can close contacts on the board or damage the battery, which will lead to a fire.
When the lid is sufficiently separated, don't pull it sharply. Open it like a book and unplug the scanner plume by gently lifting the connector lock with your nail or plastic spatula.
Dismantling an old battery and installing a new one
When you remove the back cover, you'll see the inside of the smartphone, and the battery in the Redmi Note 4 is covered by a metal plate that's screwed several times to the middle frame, and you'll need a cross screwdriver to unscrew all the visible screws that hold that protection.
Compare the number of screws and their location with the table below to avoid missing anything:
| Location of the screw | Type of screw | Function |
|---|---|---|
| The speaker (bottom) | Long. | Fixing the bottom plume |
| Near the camera | Medium. | Securing protection fees |
| On the sides of the battery | Short. | Fixing the battery frame |
| The center of the frame | Medium. | Main anchorage |
Once the metal shield is removed, disconnect the battery plume from the motherboard. Do this carefully by putting the connector up from the bottom up. The old battery is also glued to the frame on double-sided tape. You can use a thin line or plastic card to extract it, carefully cutting the glue layer.
What to do if the battery does not detach?
Install the new battery by pre-applying a thin layer of double-sided tape or B-7000 adhesive onto the frame (optional, for fixation). Connect the new battery plume to a characteristic click and make sure it lies flat, free of clamps.
Device assembly and initial start
And you do the reverse assembly, you put a metal plate in place, you twist all the screws, and it's important not to pull them over, so you don't rip the threads off the plastic seats, but you don't leave them hanging around, otherwise the case will creak.
Connect the fingerprint scanner plume to the back cover and carefully align the connectors. Press the lid around the perimeter, starting from the center to the edges, so that the latches fall into place. If you've used glue, it's advisable to press the body with rubber bands or a load for 15-20 minutes.
The first run may take longer than usual. The system calibrates the new battery and checks the integrity of the system files. If the phone is on and shows charge, but the percentage does not change when charging, software calibration may be required.
Check the touchscreen, speakers and vibrations immediately after assembly, before you stick the lid permanently, this will quickly correct the error if some plume was not fully connected.
Calibration and performance check
After a successful battery replacement, it is recommended to conduct a calibration procedure so that the power controller correctly displays the charge level. To do this, completely discharge the phone before turning off, then put it on charge when off to 100%.
Turn on the device without removing from the charge, and make sure that the indicator is 100%. After that, you can use the smartphone in normal mode. The first couple of charging-discharge cycles, the system will "learn" to work with the new battery.
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Proper calibration of the battery extends its lifespan and ensures accurate display of the percentage of charge in the MIUI interface.
Use the engineering menu to check battery status. Enter ##6484## in the dialer to get into the testing menu. Select "Battery Indicator" or "Version" to see current voltage and battery status.
⚠️ Warning: If after replacement the phone warms up in the battery area or quickly discharges (for the phone is not used) 2-3 This may indicate a defect in a new part or an incorrect connection.
Watch the heating temperature in the first days of operation. Light heating is normal when you charge fast, but a hot case in standby mode is an alarm.