How to change the battery in Xiaomi Redmi Note 8: a complete guide with photos and tips

Xiaomi Redmi Note 8

Self-replacement of the battery in the Redmi Note 8 is a medium-sized task that requires accuracy, patience and the right tools. In this article, we will go through the entire process from fault diagnosis to final assembly of the device, learn how to choose a quality battery, what tools you will need, and how to avoid typical errors that can lead to damage to the smartphone.

It's important to understand that replacing the battery will void the warranty (if it's still valid), and sloppy actions can damage the plumes, the display, or the board. If you're not sure about yourself, you'd better go to the service center. But if you're willing to take the risk, follow our instructions carefully, without rushing.

Average replacement time for beginners — 1.5-2 For the hour, for experienced users — 40-60 The cost of a new battery varies from 800 before 2500 Original Xiaomi batteries are difficult to find, but there are worthy analogues with similar characteristics.

How to know if the battery is time to change: 5 key signs

Before you start a screwdriver, make sure that the battery is the problem, and sometimes a quick discharge or a sudden shutdown is due to software failures, damage to the charging port, or a power board malfunction, and here are the exact symptoms that indicate battery wear:

🔋 A sharp drop in capacity. If the smartphone runs out of power 3-4 You can use it in moderation (social media, messengers, calls) and you used to keep it all day, which is the first bell. You can check the current capacity through applications like AccuBattery (shows wear as a percentage).

⚡ Sudden shutdowns. The phone shuts down when you're out. 20-30% charge or even 50%, And after it's turned on, 0-5%? This is a sign of degradation of lithium-polymer cells – the battery cannot hold the declared voltage.

🔥 Overheating during charging. If the body heats up to 40-50°C when you plug in to the charger, and it's very slow to charge -- probably the battery is swelling or damaged -- and it's dangerous to run a bloated battery, and it's dangerous to fire or explode!

⏳ Long charge, long charge. 0 before 100% borrower 4-5 watches instead of standard 1.5-2? This can be due to both a charging port malfunction and battery wear. check charging on another device to rule out a power supply issue.

📉 Charge jumps. Charge jumps from 50% to 20%, then back to 40%? Is it a sign of loss of contact between the battery and the power controller or damage to the thermistor inside the battery.

• 🔍 Diagnostics through the engineering menu. Enter the code ##4636##, go to Battery Information. If the Battery Health value is below 70%, it's time to change the battery.
• 📊 Check in AccuBattery. Install the app, charge the phone to 100% and discharge to 0%. The app will show the real capacity. If it is below 3000 mAh (at the initial 4000 mAh), the battery is worn out.

⚠️ Attention! If the battery is swelling (the body of the smartphone is curved, the screen is raised), immediately disconnect it from the power supply and do not use it until you replace it.

Which battery to choose for Redmi Note 8: original vs analogues

Xiaomi Redmi Note 8 is equipped with a battery type BL47 4000 mAh capacity and voltage 3.85V. Xiaomi's original batteries are hard to find, because it doesn't sell them separately, and service centers often install analogues.

When choosing a battery, pay attention to:

1. Capacity: must be at least 4000 mAh (permissible) 4100-4200 mAh analogue).
2. Type of connector: must match the original (3-pin thermistor).
3. Controller: Cheap batteries without protection can damage the board.
4. Guarantee: Reliable sellers give a guarantee of 6 months.

Where to buy:

• 🛒 AliExpress is cheaper but a long wait (2-4 Look for sellers with higher ratings 98% and photo reviews.
• 🏬 Local shops (for example, Svyaznoy, M. Video, DNS) — It is expensive, but you can check before buying.
• 🔧 Service centers – often sell batteries in bulk, you can buy at a discount.

⚠️ Avoid unlabeled batteries with suspiciously low prices (below 800) ₽) These batteries can damage the smartphone board or cause a fire.

Preparing for replacement: tools and safety

To replace the battery in the Redmi Note 8, you will need:

• 🔧 Screwdriver kit: cross-haired (PH00) and flat (1.5 mm) for the screws of the body, as well as five-pointed (Pentalobe) P2) plume.
• 🧲 Suction - for screen removal (you can use a suction cup for glasses or a special one for smartphones).
• 📏 Plastic blades or mediators - to tamper with the body and not damage the plumes.
• 🔥 Hair dryer or thermo-air station - for softening the glue (temperature) 60-80°C).
• 🧴 Isopropyl alcohol (90%+) — glue-residue.
• 🔋 New battery – proven manufacturer (see table above).
• 📦 Container for screws - so as not to lose small parts (you can use a magnetic mat).

Also prepare the workplace:

• 🪑 Work at a table with good lighting.
• 🔌 Turn off the smartphone from the power supply and take it out SIM-map.
• 📱 Discharge the battery before 20-30% — This will reduce the risk of fire in case of accidental damage.
• 🧤 Wear an antistatic bracelet or periodically touch a grounded metal object to remove static electricity.

What can't be done:

• ❌ Using metal tools to tweak the body - this will damage the plumes.
• ❌ Apply excessive force when removing the screen - you can tear off the display plume.
• ❌ Puncture or bend the battery – the risk of electrolyte leakage or fire.
• ❌ Work without power out – even a discharged battery can give a spark.

Step-by-step: how to disassemble the Redmi Note 8 and replace the battery

Now, to the most important step, the dismantling of the smartphone and the replacement of the battery, follow the instructions strictly by steps, without missing points.

Step 1: Removing the back cover

1. Turn off the phone and put it down with the screen.
2. Heat the hair dryer around the perimeter during 2-3 minutes (temperature) 60-70°C. This will soften the glue.
3. Place the suction cup at the bottom of the body (near the connector). USB-C) and pull up.
4. In the resulting gap insert a plastic spatula and gently run it along the edge, separating the lid.

Step 2: Disconnect battery plumes

1. Remove 11 screws holding the metal plate (they are of different lengths – remember the location!).
2. Carefully slap the plate and put it aside.
3. Disconnect the battery plume with a plastic spatula (don’t pull the wires!).
4. Turn off the plume of the display module (located nearby, under metal protection).

Step 3: Remove the old battery

1. Put a plastic blade on either side of the battery, and if it's glued heavily, put a few drops of isopropyl alcohol under it, and wait. 1-2 minute.
2. Carefully pull on a special black tape (pull-tab), if you have one. If not, continue to slap the battery around the edges.
3. If the battery doesn't respond, apply the alcohol again and wait.

Step 4: Installation of a new battery

1. Check the contacts of the new battery – they should be clean, without oxidation.
2. Stick bilateral tape (comes complete with battery) or apply a thin layer of glue B-7000.
3. Connect the new battery plume to the board (make sure the connector sits tight).
4. Put the battery back in place, slightly pressing it.

Step 5: Assembly of the phone

1. Connect the display plume and fasten the metal plate with screws (watch the length!).
2. Make sure all plumes are connected correctly and the screws are twisted to the point (but not pulled!).
3. Stick the back cover. You can use glue for reliability. B-7000 double-scotch.
4. Place your phone under a press (such as a stack of books) 10-15 minutes to get the glue together.

Don't turn on the phone right away after assembly! 30-60 minutes to make the glue finally dry.

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Before you first charge the new battery, completely discharge it to 0%, then charge it to 100% without interruption, which will help calibrate the charge controller.

Common Mistakes and How to Avoid Them

Even with careful disassembly, you can make mistakes that will cause your phone to fail, and here are the most common problems and ways to prevent them:

🔧 Damage to the display plume

• Reason: too strong pressing on the screen or careless disconnection of the plume.
• How to avoid: use only plastic shoulder blades, do not pull the plume with metal tools.
• Solution: If the screen doesn’t work after assembly, check the connection of the plume or replace it (cost) ~1500 ₽).

🔋 The battery does not hold the charge after replacement

• The reason: poor-quality battery without a controller or improper connection of the plume.
• How to avoid: Buy batteries with overcharging/discharge protection (see table above).
• Solution: Check the voltage on the battery contacts with a multimeter (should be ~3.7-3.8V).

📱 The phone will not turn on after assembly.

• Reason: not connected battery plume or board, short circuit.
• How to avoid: Before assembly, check all connections with a multimeter in the "vertebrate" mode.
• Solution: Take the phone apart and check the connection of all the plumes. If it doesn't work, contact the service.

🔥 Bloating of the new battery

• Reason: Use of a non-original charger or overheating.
• How to avoid: Charge your phone with only original or certified RAM (5V/2A or 9V/2A).
• Solution: If the battery is swelling, turn off the phone immediately and replace the battery.

⚠️ Attention! If after the battery change, the phone starts to warm up, turn off or show charging errors, this is a sign of short circuit or damage to the power controller!

Calibration of the new battery: why it matters

After a battery change, many users find that the phone shows an incorrect charge level: for example, immediately after a charge is turned off, it drops from 100% to 80%, or turns off at 20%, this is due to a mismatch between the data of the charge controller and the real capacity of the new battery.

To avoid this, perform calibration:

1. Completely discharge the phone before turning off.
2. Connect the original charger and charge up to 100% without interruptions (don’t turn off the cable!).
3. After the 100% Keep your phone on charge again. 1-2 hour.
4. Turn off the charger and use the phone until it is completely discharged.
5. Repeat the charging-discharge cycle 2-3 times.

You can also use the engineering menu:

1. Enter the code ##4636##.
2. Go to Battery Information.
3. Press the Battery Calibration (if the option is available).

After calibration, the charge level should be displayed correctly, and if the problem persists, it may be that the battery is poor or the power controller on the board is damaged.

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Calibration of the new battery is mandatory! Without it, the phone may show an incorrect charge level, which will lead to sudden blackouts or recharge.

Frequent questions about battery replacement in the Redmi Note 8