Why Change the Battery on the Redmi Note 7 and When to Change
Xiaomi Redmi Note 7 was released in 2019, and even with careful use after 3-4 years, its battery begins to lose capacity. If your device quickly discharges, turns off at 20-30% charge or the body is swollen, it's time to think about replacing the battery. The original Li-Po 4000 mAh battery is designed for 500-800 charging cycles, after which the capacity drops by 20-30%.
Self-replacement costs 3-5 times less than a service center, but requires care. This article provides detailed instructions with nuances that will not be told in short YouTube videos. We will learn how to turn off power before disassembling, what tools you will need and how to avoid errors when connecting a new battery, and you will learn which battery models are compatible with the Redmi Note 7 and where to buy them without the risk of running into a fake.
What tools will be needed to replace
Without the right tools, it's almost impossible to disassemble the Redmi Note 7 -- the body is pressed on a sealant, and the battery plumes are fragile.
- 🔧 Plastic blades (2-3 - for gently putting the lid and disconnecting the plumes. Metal tools can damage the body!
- 🔨 The screwdriver. PH00 — The usual screwdriver won't work, because the screw heads are very small.
- 🔥 Hair dryer or thermo-air station - for softening the glue (temperature) 60-80°C) The lid cannot be removed without heating.
- 🧲 Magnetic mat or tray - so as not to lose the screws (there are 12 pieces!).
- 🔋 New battery - original MBJ405830 or a qualitative analogue (for example, from Baseus or Remax).
- 🧴 Isopropyl alcohol 90%+ — glue-cleaner.
- 📏 Plastic scraper – to remove old glue from the frame.
If you don't have a thermophen, you can use a regular hair dryer, but you need to keep it at a distance of 10-15 cm to avoid overheating the screen. Never use an open fire (lighter, matches) - this can damage the display and plastic parts!
Preparing the smartphone for dismantling: steps before removing the lid
Before you start disassembling, you need to completely turn off the device and protect it from static electricity.
Turn off the smartphone long hold power button
Extract. SIM-card and memory card (if any)
Charge your phone to 30-50% (to avoid short circuits)
Remove the cover and protective glass (if any)
Prepare your workspace: a clean desk, good lighting, no carpets (they accumulate static electricity)-->
Pay special attention to disabling biometric protection. If your Redmi Note 7 has a fingerprint or facial recognition set up, delete this data in the settings (Settings → Passwords and Security → Fingerprints). Otherwise, the scanner may not work properly after assembly.
⚠️ Warning: If you have recently dropped your phone or if there are cracks on the case, check the integrity of the display before replacing the battery!
Step-by-step: how to remove the back cover
The most important step is to carefully separate the lid, and the main thing is to take your time and warm up the glue evenly around the perimeter.
- Heat the body. Turn the hair dryer on at medium power (60-70°C) and warm up the edges of the back cover for 2-3 minutes. Move the hair dryer around, paying special attention to the corners - there is the most glue.
- Separate the cover. Put the plastic blade in the gap between the lid and the frame (start at the lower right corner where the SIM card is located). Carefully drive the blade along the body, gradually detaching the lid. If the glue does not respond, warm up again.
- Remove the cover. When the lid is 2/3 apart, don't remove it completely! Underneath it are the plumes of the fingerprint scanner and antenna, gently lift the lid and disconnect the plumes with a shoulder blade.
Inside, you'll see the battery locked in a black film. Don't try to pull it out right away, it's glued to the body! First, you need to disconnect the power connector.
What to do if the lid is not removed?
Disconnecting and removing the old battery
Now you need to turn off the phone and carefully remove the battery, and this step requires the utmost care - one wrong movement can lead to a short circuit!
First, disconnect the battery connector from the motherboard, and it's under a black cover (which you need to put in a blade), and the connector is fixed by a latch, and you can gently pull it up, and then you can pull the plug out, and then you can start removing the battery itself.
| Step. | Action. | Tool. |
|---|---|---|
| 1 | Unplug the protective film from the battery (it is glued weakly, removed by hands) | Fingers or tweezers |
| 2 | Put a plastic shoulder blade on the battery from any corner. | Plastic spatula |
| 3 | If the battery fails, warm it up with a hair dryer (max. 60°C!) for 1 minute. | Fen |
| 4 | Take the battery out carefully without bending it (risk of damage!) | Hands + spatula |
| 5 | Clean the frame from glue residues with isopropyl alcohol | Cotton swab + alcohol |
⚠️ Attention: If the battery is swelling (see the bulge on the lid), do not try to prick it! Bloated batteries can ignite when mechanically exposed.
Installation of a new battery and assembly of the phone
Before installing a new battery, check it for external defects. The original battery for the Redmi Note 7 is labeled MBJ405830 and has a capacity of 4000 mAh. If you bought an analog, compare its dimensions to the old battery - they should match up to a millimeter.
The installation is carried out in reverse order:
- Stick the new battery onto double-sided tape (comes with it) or apply a thin layer of B-7000 glue.
- Connect the power connector to the motherboard (it should be snapped with a slight click).
- Put the print scanner and antenna plumes in the slots on the lid.
- Close the back cover, starting from the top (where the plumes are located), and snap it around the perimeter.
- Twisted all 12 screws with a cross screwdriver (do not pull!).
After assembly, don't turn the phone on right away! Let the glue dry for 10-15 minutes. Then plug in the charger and check if the new battery is recognized by the system.
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If the battery is discharged quickly after replacing, calibrate: completely discharge the phone before turning off, then charge to 100% without interruptions. Repeat the procedure 2-3 times.
Frequent Mistakes and How to Avoid Them
Even with a careful replacement, you can make mistakes that will lead to a broken smartphone, and here are the most common problems and solutions:
- 🔌 The phone doesn't turn on after assembly, and the reason is that the battery connector or the power train is not connected.
- 📱 The screen flickers or doesn't respond to touch, and the reason is that the plume of the display is damaged when disassembled, solution: gently reconnect the plume or replace it.
- 🔋 The battery is not charging, and the reason is: a faulty charging controller or a damaged charging controller. USB-Solution: Check the port for debris, try another charger.
- 🔊 The speaker or the microphone is not working, and the reason is that the audio module plume has disconnected. Solution: disassemble the phone and plug the plume back in.
If the Redmi Note 7 started to overheat after replacing the battery, chances are you've installed a poor-quality battery.The original Xiaomi batteries should not heat above 40°C when charging. Check the temperature using the AIDA64 app (Sensors section).
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If the phone does not turn on after replacing the battery, do not panic - in 90% of cases the problem is solved by re-checking the connection of plumes and connectors.