Xiaomi Redmi Note 7 battery replacement: the full guide

Xiaomi Redmi Note 7 smartphones have earned a reputation for being “long-lived” thanks to their capacious 4,000 mAh batteries. However, even the highest-quality lithium polymer cells degrade over time, losing their ability to hold charge. If your phone starts to run out in a couple of hours or turns off by 20%, it’s time to think about replacing the battery.

Replacing a power source on its own is not only a way to save on service center services, but also an opportunity to be confident in the quality of the installed component. The process requires accuracy and the presence of a basic set of tools, but it is quite possible for the user with straight hands. In this article, we will discuss in detail each step of the procedure, from preparation to the final calibration of the new battery.

Before starting work, it is important to understand that opening the case automatically deprives the device of an official warranty if it is still valid. However, for the Redmi Note 7 model released a few years ago, this factor usually does not play a role anymore.

Tools and workplace preparation required

The quality of the repair depends on preparation. You do not need a professional engineer's desk, but a clean, well-lit place and no dust are required. To work with the Xiaomi Redmi Note 7, you will need a specific set of tools that can be purchased from any radio parts store or marketplace.

The main tool will be a dryer or heat pad to soften the glue. A normal household hair dryer may not give the desired temperature, so it is better to use a construction (carefully!) or a special heating tablet. Also critical is the presence of a suction cup to open the case and a set of plastic blades (mediators) that will not scratch the metal.

Here is a complete list of what should be on your desk before the start of the showdown:

• 🛠️ Set of screwdrivers (necessarily cross) PH000 and Phillips #00).
• 🔥 A hair dryer or heating panel to warm the edges.
• 🏴 Suction and plastic mediators for opening.
• 🧲 Magnetic substrate for sorting screws.
• 🧹 Isopropyl alcohol and toothbrush for cleaning old glue.

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Use a magnetic substrate or a piece of paper with painted cells to avoid confusing screws of different lengths. Swipe a long screw into a short hole can break through the motherboard.

Pay special attention to the new battery. Buy parts only from trusted suppliers, paying attention to the BN46 label. This is the standard battery code for this model. Cheap counterparts without a brand often have a real capacity of half the declared.

The process of safe disassembly of the smartphone

The first step should always be to shut down the device completely.Do not try to change the battery while the phone is in sleep mode or on, this can lead to a short circuit. SIM-cards so as not to damage its mechanism when heated.

Next comes the most important step - heating the perimeter of the back cover. Turn on the hair dryer and evenly warm the edges of the smartphone for 2-3 minutes. The temperature should not exceed 80-90 degrees, so as not to damage the matrix of the screen on the back. Periodically check the heating with your finger: if the hand is hot, but tolerant - the temperature is suitable.

⚠️ Warning: Do not direct the jet of hot air into the center of the rear panel where the camera and flash are located. Local overheating can damage the optical stabilization of the lens or cause the camera module to detach.

After warming up, stick the suction cup at the bottom of the back cover and gently pull up, creating a small gap. Insert a plastic blade into the resulting gap and, without removing it, lead along the perimeter, cutting the adhesive layer. Move slowly, trying to keep the blade parallel to the plane of the body, so as not to touch the internal components.

When the lid is peeled off around the perimeter, don't open it up like a book, and you have a fingerprint scanner plume stuck inside the lid that leads to the motherboard, and you're guaranteed to plow the plume out of the lid, and you're going to bend the lid back minimally to get access to the security screws.

Dismantling an old battery and installing a new one

When you take the back cover off, you'll see the inside of the smartphone, and the battery is covered with a metal bar that's attached to a few screws, and there's usually about 10 screws, and they can be of different lengths, so remember which cog is twisted from where.

When you take the bar off, you'll see the battery connector connected to the motherboard, and the first thing you need to do is turn off the battery plume, use a plastic blade, gently pull the connector up, and then you can start removing the battery itself after you turn it off.

The old battery in the Redmi Note 7 is glued to double-sided tape, and you can't pull it over the top edge, which can cause the shell to puncture and residual charge to ignite. There are two safe ways to retrieve it:

• 💧 Drip a little isopropyl alcohol under the edges of the battery and wait 5 minutes until the glue softens.
• 🧵 Carefully stretch a thin line or dental floss under the battery and the movements of the "sawing" to separate it from the body.

Clean the inside of the case of the residues of old glue with alcohol and soft cloth. The new battery should lie perfectly flat. If the new battery has adhesive tape, use it. If not, you can use special adhesive strips to repair smartphones (B-7000 glue is better not to pour in, only on the edges).

Device assembly and plume inspection

When you install a new battery and plug the plume into the box before you click, don't rush to close the case. Initial health check is critical. Press the power button. If the screen catches fire and the phone starts to load, half the job is done.

Check the basic modules: the camera, the touchscreen, the speakers, and of course the fingerprint scanner. If the scanner doesn't work, you may have damaged the plume at the opening or you didn't connect it well. In the Xiaomi Redmi Note 7, the scanner plume is very thin and sensitive to clogs.

Once you make sure everything is working properly, you can start the final assembly. Lay the plumes carefully so they are not stretched. Press the metal bar and twist all the screws. Then apply a thin layer of B-7000 glue or use factory duct tape around the perimeter of the back cover for sealing.

⚠️ Warning: Don't use superglue (cyanacrylate) to stick the lid! its vapors can settle on the camera and speakers, permanently spoiling them, and the glue itself makes the glass brittle and can damage it on the next repair.

Press the lid with rubber harnesses or put a load on top for 15-20 minutes to polymerize the glue. After that, wipe the case from the residue of the glue, the device is ready for use.

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Proper assembly guarantees not only aesthetics but also protection from dust and moisture (although the factory IP level will not be fully restored).

Calibration of the new battery

Once installed, the new battery may display an incorrect percentage of charge, because the power controller has not yet “acquainted” with the actual capacity limits of the new cell, and for the system to work properly, a calibration procedure must be performed.

The idea is simple: completely discharge the phone until it turns off automatically. Then, without turning it on, charge to 100%. After reaching full charge, keep charging for another 1-2 hours. Then force the device to restart.

You can use an engineering menu or special commands to calibrate more accurately, but for the average user, 2-3 full discharge-charge cycles are enough to help the MIUI controller to correctly plot the discharge schedule.

In some cases, resetting battery statistics through ADB helps, but it requires a computer connection and drivers.

adb shell dumpsys batterystats --reset

You only need to use this command if you're a confident PC user, and in most cases, natural cycle calibration is enough.

Common mistakes and frequent questions

Beginners often make mistakes that can cost a device life. One of the most common is damage to the display plume when it is unsavoryly opened. The screen in Redmi Note 7 is glued to the frame pretty tightly, and an inexperienced craftsman can crack the matrix glass.

Also, cleaning contacts is often ignored. If the contacts of the battery or board are left with oxidized plaque, the phone may not see charging or quickly discharge.

The following are the answers to the most common questions that arise after replacement:

Replacing the battery is a way to extend the life of your favorite gadget. If you follow all the instructions and use quality components, the Xiaomi Redmi Note 7 will once again delight you with autonomy comparable to the new one.