Smartphone Xiaomi Redmi Note 3 at one time became a hit with sales thanks to the metal body and a powerful battery with a capacity of 4000 mAh. However, time does not spare lithium-polymer batteries, and even the most reliable gadget eventually begins to discharge before the eyes. If your device turns off at 20-30% charge or the rear window is blown up, it's time to think about replacing the battery. This will not only return the former autonomy, but also protect the internal components from possible damage to the bloated battery.
The process of replacing the power source in the Redmi Note 3 (the Pro/SE version with the index Kenzo and the Kate version) has its own features that distinguish it from the simpler plastic models. Here you will encounter a metal case that requires careful heating and use of a suction cup, as well as a fingerprint scanner plume that damages if you carelessly handle. In this article, we will discuss all the steps from choosing a spare part to the first charge cycles so that you can perform the repair yourself and save on the services of the service center.
Before you start the action, you need to prepare the workplace and tools. You will need not only a new battery, but also a set of precision screwdrivers, a plastic shovel, a suction cup and, preferably, a hair dryer or thermophen to warm the perimeter of the case. Ignoring safety rules can damage the plumes or even burn the old battery, so carefully study the theoretical part before starting practical work.
Diagnostics and selection of a new battery
The first step is to accurately diagnose the status of the current power source. Often users confuse the software failures of the charge controller with the physical degradation of the battery chemistry. If the phone keeps the charge off for a long time but sits down quickly while working, you may need to calibrate or flash it. However, if the screen shows artifacts, the body is deformed, or the phone turns off immediately after connecting energy-intensive applications, a replacement is inevitable. Visual inspection through a magnifying glass will help to detect bloating - the battery should not have bulges.
When choosing a new part for Xiaomi Redmi Note 3, it is critical to pay attention to the label and manufacturer. The original batteries have the model code BM46. There are many copies on the market that may have a declared capacity of 4000 mAh, but in reality have much lower rates. A quality battery should have a protective board with a controller that prevents overcharging and deep discharge. Cheap analogues are often lacking proper protection, which creates a risk to the device.
Pay attention to the date of production, indicated on the packaging or the element itself. Lithium polymer batteries tend to age even without use. Buying a part that has been in storage for more than two years may not give the desired increase in autonomy. It is also worth checking the availability of holograms and the quality of logo printing, since counterfeits are often issued with low quality printing.
⚠️ Warning: Never use a bloated battery to charge or store in the house. A deformed case violates the tightness, and if you short circuit, you can ignite the electrolyte.
Tools and workplace preparation required
You can't do a good job without the right tools. You'll need a specific set to disassemble the Redmi Note 3, because standard household screwdrivers can rip off screw hats or damage plastic latches. The main tool is a set of precision screwdrivers that includes PH00 and PH000 cross-bits, which are used to twist screws that lock the metal frame and board.
The second important element is the heat source. Xiaomi's metal body is glued around the perimeter with a special adhesive compound that softens when heated to 80-90 degrees Celsius. Using a household hair dryer is possible, but it takes longer; a professional thermophen or heating pad will greatly speed up the process. Remember that overheating the display can cause yellow spots or touchscreen detachment, so only heat the contour of the case.
- 🔧 Precision screwdrivers (cross-hatched) PH00, PH000 flat).
- 🔥 Dryer, thermophene or electric heating pad for heating the body.
- 🖐️ Glass suction cup and plastic spatula (mediator) for opening.
- 🧲 Magnetic mat or organizer for sorting screws of different sizes.
The workspace is a key to success. The screws in Redmi Note 3 are of different lengths and threads. If you confuse them with places when you build them, you can punch through the body or damage the threads in the landing holes. It is recommended to use a magnetic mat with markings or simply spread the screws on a piece of paper in the order of their twisting, signing the steps.
☑️ Preparation for disassembly
The process of disassembling the Redmi Note 3 body
We're going to start disassembling the device directly. SIM-This is standard procedure, but it is often forgotten, which can damage the tray when you try to remove the back cover. After removing the tray, carefully inspect the perimeter of the device for visible damage or traces of previous autopsies.
Next, warm up. Turn on the dryer at medium temperature and evenly warm up the ends of the smartphone for 2-3 minutes. Keep the hair dryer at a distance of 3-5 cm from the surface, constantly moving it so as not to overheat one point. The metal conducts heat well, so the insides can also warm up. After warming up, apply a suction cup to the bottom of the back cover (under the Mi logo) and gently pull up, while inserting a plastic blade into the resulting gap.
Move around the perimeter, gradually snapping the plastic latches. Don't use excessive force: if the lid does not respond, then the glue in this place has not yet warmed up. Repeat the heating procedure. Be especially careful in the top of the smartphone, where the fingerprint scanner plume is located. A sharp jerk can lead to a break in the plume, which will require its replacement or soldering.
What to do if the fingerprint scanner plume is broken?
Removing the old battery and installing a new one
Once you successfully remove the back cover, you'll have access to the internal components. The battery in Redmi Note 3 is covered by a metal shield plate that is screwed up by several screws. Carefully unscrew them using the PH000 screwdriver and remove the plate, and underneath it you'll see a battery plume connector connected to the motherboard.
The first thing you do is turn off the battery plume. Use a plastic blade or nail to hold the connector up. Never use metal tools to turn off the plumes, because it can cause the circuit board to short out. Once the plume is turned off, you can start removing the battery itself. It's attached to double-sided tape, so you can't just pull it out.
Use a plastic card or a special spatula to remove the old battery. Carefully prick the battery from different sides, trying not to damage its shell. If the battery is swelling, be extremely careful - puncture of the shell can lead to ignition. After removing the old battery, clean the landing place of the remnants of the old glue with alcohol or a special solvent. On the new battery, paste strips of a new two-sided tape and install it in place, connecting the plume before clicking.
| Parameter | Original (BM46) | Quality copy | Cheap forgery |
|---|---|---|---|
| Capacity | 4,000 mAh (real ~3900) | 3500-3800 mAh | 2000-2500 mAh |
| Weight. | ~85 grams | ~75-80 grams | ~50-60 grams |
| Protective fees | Yes, with the Xiaomi markings | Yes, without markings. | Absent or simplified |
| Term of service | 500+ cycles | 300-400 cycles | 50-100 cycles |
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Before final assembly, check the touchscreen and display by plugging in the plumes and turning on the phone. Make sure the device charges and sees a new battery.
Device assembly and battery calibration
The assembly is done in reverse order. Place the metal plate over the battery and twist all the screws. Make sure that no screw is left out. Then gently apply the back cover, combining all the protrusions, and press the perimeter to the characteristic clicks of plastic latches. For better sealing, you can slightly warm up the edges of the case with a hairdryer after assembly, so that the glue is finally activated.
After the first installation of the new battery, the system may not correctly display the level of charge. To the power controller “remember” the real capacity of the new battery, it is recommended to conduct a calibration procedure. Completely discharge the smartphone before automatically turning off. Then put it on charge when off to 100%. After reaching full charge, keep it on charging for another 1-2 hours.
Repeat the full discharge and charge cycle 2-3 more times, which will help Android and MIUI correctly calculate the discharge curve. Modern versions of MIUI also have a hidden menu of engineering tests where you can run automatic calibration, but the manual method through charge cycles is considered more reliable for older models.
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Proper calibration of the battery after replacement is a mandatory step that avoids rapid discharge and incorrect display of charge percentages in the first weeks of use.
Typical errors and troubleshooting
In the process of replacing the battery, users often face a number of problems, and one of the most common is that the phone doesn't turn on after assembly. In 90% of cases, this means that the battery plume is not fully inserted into the connector or skewed. Disassemble the device again and check the density of the connection. It's also worth checking if you damaged the plume itself when you were not working sloppy with the blade.
Another common problem is the lack of response to charging or constant reboots, which may indicate a poor quality of the new battery or a faulty charge controller on the motherboard. If the new battery also discharges quickly or warms up, you may have been sold a defective item. In such cases, it is necessary to check the voltage at the contacts of the battery with a multimeter (should be about the 3.7-3.8 V).
- 🔋 Phone does not turn on: check the connection of the battery plume and the display plume.
- 🔄 Constant reboots: Maybe bad contact or new battery failure.
- 📱 The fingerprint scanner does not work: the plume is damaged during disassembly or the connector has moved away.
- 🔥 Strong heating of the body: short circuit or battery defect, immediately turn off!
⚠️ Warning: If after the battery change, the phone starts to warm up strongly in the area of the camera or processor, immediately stop using.This may indicate a short circuit on the board caused by sloppy assembly or defective parts.
And the software part is also important. Sometimes, after you change the battery, you need to reset your Windows Data/Factory Reset, especially if you're experiencing strange percentage surges, but you should only use this method after you've eliminated hardware problems. Always back up your important data before you do the reset.