Xiaomi Redmi 8T is one of the most popular budget smartphones of 2019, but even its reliable battery capacity of 5000 mAh begins to lose capacity in 3-4 years. If your device discharges in a couple of hours, turns off 30-40% of charge or overheats when charging, it’s time to replace the battery. In this article, we will discuss how to do it yourself without contacting the service center.
The process of replacing the battery with the Redmi 8T (codename willow) is more complicated than on models with a removable back cover, but even a beginner can cope with the right approach. The main thing is to have patience, a quality tool and follow the instructions. We will describe in detail each step from choosing a new battery to calibrating after installation, and also reveal the features of attaching the battery plume in this model, which are often missed in general manuals.
1. Signs of battery wear: when exactly a replacement is needed
Before you start disassembling, make sure that the problem is in the battery.
- 🔋 The smartphone is running out of power. 10-15% post 10-15 minutes without load (for example, in standby mode).
- 🔥 The body is noticeably heated in the battery area when charging or using.
- ⚡ The charge level “jumps” (for example, from 40% immediately to 15% after rebooting).
- 🛑 The phone turns off when 20-30% charge and not activated without connection to charging.
- 📉 Battery life has been reduced in 2-3 time compared to the new state.
If you see at least 2-3 items from the list, the battery is worn out. For an accurate diagnosis, check the status of the battery through the engineering menu:
- Type on the keyboard ##4636##.
- Select the Battery Information item.
- If you look at the Health parameter, if it's below 70-75%, you should change the battery.
⚠️ Attention: On Redmi 8T firmware MIUI 12 and above, the engineering menu can be blocked, in which case use applications like AccuBattery (available on Google Play).
2. Selection of a new battery: original vs analogues
The battery quality is not only the life of the battery, but also the safety of the device, with three types of batteries available for the Redmi 8T:
| Type | Advantages | Deficiencies | Price (2026) |
|---|---|---|---|
| The original (Xiaomi) | Guaranteed compatibility, optimal life (500-600 cycles), safety | High cost, risk of running into a fake | 1800–2500 ₽ |
| Analogues (Green Cell, Baseus) | Price 1.5-2 times lower than the original, often exceeding capacity (up to 5200 mAh) | Quality depends on the manufacturer, there may be problems with calibration. | 900–1500 ₽ |
| Budget (no-name) | Minimum price | High risk of bloating, low resource (200-300 cycles), possible problems with the controller | 500–800 ₽ |
For the Redmi 8T, the best choice is the original battery with the MB-J12 article or certified analogues from Green Cell (model GC-RM8T-5000) or Baseus (series Power Bank Inside).
- 📦 Packaging: The original must have a hologram, serial number and QR-code to check on Xiaomi website.
- 🔧 Contacts: The battery must have 3 contacts (plus, minus, thermistor) and markings 4.44V.
- 📏 Dimensions: Thickness - 3.85 mm, length - 73 mm, width - 70 mm. deviations more than 0.5 mm indicate a fake.
⚠️ Warning: Batteries over 5000 mAh (e.g. 5200 or 6000 mAh) often have understated real capacity!
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Before buying, ask the seller to send a photo of the battery from both sides - so you can check the marking with the original.
3. Tools and preparations for replacement
To replace the battery with the Redmi 8T, you will need:
New battery (compatibility tested)| Plastic blades (2-3 pieces) or mediators | Cross screwdriver (PH00 or PH0) | Screen sucker (optional) |Fen or thermoair station (to soften glue) |Tweezers (preferably magnetic) |Isopropyl alcohol (90%+) and cotton swabs | Double-sided tape or B-7000 glue (to fix new battery)
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Pay special attention to plastic blades - metal tools can damage plumes or body. If you do not have a hair dryer, you can use a regular household, but with a minimum temperature (to avoid melting the plastic).
Before the disassembly:
- Turn off your smartphone and remove it. SIM-memory-card.
- Discharge the battery to 20-30% – this minimizes the risk of short circuit.
- Make a backup of the data (in case you have to reset the settings).
- Work on a clean, well-lit surface (it is better to cover the table with white cloth, so as not to lose small details).
If you've never taken a smartphone apart, practice on an old device or watch Redmi 8T video disassembly on YouTube (like Repair Guru) to help you understand how hard you can push the latches.
4. Step-by-step instructions for disassembling and replacing the battery
Disassembly of the Redmi 8T requires care - the body is glued around the perimeter, and the battery plume is soldered to the motherboard.
Step 1: Removing the back cover
Heat the edge of the body with a hair dryer around the perimeter for 2-3 minutes, keeping it at a distance of 5-7 cm. The temperature should not be higher than 60 ° C. After warming up:
- Insert a plastic blade into the gap between the case and the screen at the charging connector.
- Carefully drive the shoulder blade along the edge, snapping the clamps. Start at the bottom, there's less glue.
- If the lid fails, warm up again and try again.
Step 2: Shutting off the battery
When you remove the lid, you'll see the battery covered by a metal plate, unscrew the 10 screws (marked with the red circles in the photo below) and remove the plate.
- Disconnect the battery plume by sliding it with a spatula on the side (not up!).
- Check the voltage on the contacts with a multimeter - it should be in the range of 3.7-4.2V.
Step 3: Remove the old battery
The battery is glued to the body to remove it.
- Put a plastic shoulder blade on the battery from any angle.
- Pull slowly, pouring isopropyl alcohol under the battery (it dissolves the glue).
- If the battery is swelling, do not pierce it - it can lead to fire!
⚠️ Attention: On Redmi 8T The battery plume is short and fragile. Don't pull it, just the battery case!
Step 4: Installation of a new battery
Before installing the new battery:
- 🧹 Clean the place under the battery from glue residues with alcohol.
- 🔌 Check the contacts on the motherboard – they should be clean and not oxidized.
- 📏 Make sure the new battery fits tightly into the groove (without gaps).
Stick the battery with double-sided tape or B-7000 glue (ply a thin layer around the perimeter). Connect the plume and lock the metal plate.
Step 5: Assembly of the phone
Collect the phone in reverse order:
- Set the back cover by aligning the latches.
- So, put the slack on the edges (to make sure the slack is tight).
- Turn the screws (do not pull!).
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On Redmi 8T after replacing the battery be sure to perform calibration - otherwise the charge indicator will show incorrect values.
Calibration of the battery after replacement
The new battery requires calibration to allow the charge controller to correctly determine its capacity.
Step 1: Complete discharge
- Turn on the phone and discharge it until it is automatically turned off.
- Wait 3-4 hours and try to turn it on again (repeat until it turns on).
Stage 2: Full charge
- Connect the original charger (power 18W).
- Charge to 100%, then leave on charging for another 1-2 hours.
- Turn off and turn on the phone again. Repeat the charging-discharge cycle 2-3 times.
After calibration, check the time in Settings → Battery → Battery Use. Normally, the screen should hold a charge of 6-8 hours when used actively.
What if the phone doesn’t turn on after the replacement?
6. Frequent mistakes and how to avoid them
Even experienced craftsmen sometimes make mistakes when replacing the battery with the Redmi 8T.
- 🔧 Tug-tug screws → It causes cracks in the motherboard. Use a screwdriver with a torque limiter.
- 🔥 Overheating when the lid is removed → The plastic is deformed or the touchscreen is peeled off. 5-7 centimeter.
- ⚡ Short circuit. → This happens when you touch the battery's contacts with metal tools.
- 📉 Wrong calibration → The battery is discharged quickly. Always do it. 2-3 full-cycle.
If the battery is discharged faster than before after replacement, check:
- The quality of the plume contact (sometimes it departs during assembly).
- Energy saving settings (Settings → Battery → Energy saving mode – must be turned off).
- Background processes (use AccuBattery to analyze the flow rate).
7. Alternative options: when you should not change the battery yourself
Self-replacement of the battery is not always justified.
- 🛠️ You have no experience disassembling electronics (risk of damaging plumes or motherboard).
- 💥 Battery swells or leaks (it is dangerous - fire is possible!).
- 🔄 Phone for warranty (self-repair cancels it).
- 📱 Charging problems are not battery related (e.g., a faulty power controller).
The cost of replacement in the service varies from 1500 to 3000 ₽ (Official Xiaomi service centers use original parts, but the price there is higher than in private workshops.
If you still decide to repair the phone yourself, but are afraid to damage it, consider buying a used Redmi. 8T On Avito or Yula, these machines are sold for 3000-5000. ₽ — It’s cheaper than paying for a broken device.