Why the Redmi Note 8T Battery Fails and When to Change It
Smartphone Xiaomi Redmi Note 8T, released in 2019, is equipped with a non-removable battery capacity of 4000 mAh. Despite the stated resource in 500-800 charging cycles, after 2-3 years, many users face problems: the phone discharges in a few hours, turns off at 20-30% charge or does not hold charging.
The main signs that the battery is time to replace:
- ⚡ Fast discharge – the smartphone sits down in 3-4 hours with moderate use (previously held the day).
- 🔋 Jumping percentage of charge – the indicator jumps from 50% to 20% or the phone turns off by 10-15%.
- 🔥 Overheating – the body heats up even when simply charging or in standby mode.
- ⚠️ Battery bloating – the screen or back cover begins to “step away” from the housing.
If you notice at least two of these symptoms, battery replacement is inevitable, and the service center will charge you between 1,500 and 3,000 rubles, but with the tools and patience, you can do it yourself, saving up to 70% of the cost, and the main thing is to follow the instructions and avoid common mistakes.
What tools and materials will be needed
To replace the battery Redmi Note 8T will require a minimum set of tools, most of which can be found in the remakes for smartphones (cost from 300 rubles) or order separately.
| Tool/material | Appointment | Where to buy |
|---|---|---|
| Plastic mediator (2-3 units) | Separation of the shell without scratches | AliExpress, electronics stores |
| Cross screwdriver PH00 | Rear cover screw twisting | Any hardware store |
| Suction (optional) | Raising the screen after heating | Smartphone repair kits |
| Fryer-dryer | Softening the glue under the lid | Household appliances |
| New battery (original or analogue) | Replacement of a worn-out battery | AliExpress, Beru, local services |
When choosing a battery, consider the capacity (should match the original 4000 mAh) and the quality of the contacts. Cheap counterparts often have thin wires that can fall off when connected.
- 🔹 The original battery (article MB-J10BR) is expensive but reliable.
- 🔹 Quality analogues from Baseus, Remax or ZMI are cheaper by 30-50%.
- 🔹 Used batteries with disassembly is risky, as the resource may be running out.
⚠️ Warning: Do not use metal tools (knives, screwdrivers) to smack the lid - this will damage plastic latches and can lead to cracks on the screen. Plastic mediators are safer!
Preparing the smartphone for disassembly: steps before replacing
Before you start disassembling, you need to ensure the safety of both the device and yourself.
Turn off your smartphone and remove it. SIM-map|Charge your phone to 30-50% (do NOT charge your battery!)|Make a backup of the data (in case of errors)|Prepare the workplace: clean desk, good lighting|Wear an antistatic bracelet (optional but recommended)-->
If the Redmi Note 8T case is deformed, do not attempt to charge or turn it on, as this may cause the lithium polymer battery to ignite or explode.
- Move your phone to a non-combustible place (for example, on ceramic tiles).
- Do not puncture the battery - the gas released is toxic.
- Use protective gloves when disassembling.
It is also worth considering that after replacing the battery, the smartphone may require a reset (due to a power outage).
- 📱 Contacts (export to VCF or sync with Google Account).
- 📸 Photos and videos (copy to PC or cloud).
- 🔑 Application passwords (use Xiaomi Cloud or Google Password Manager).
💡
If the phone does not turn on after replacing the battery, try to press the power button for 20-30 seconds - this will drop the residual charge in the capacitors.
Step-by-step: how to disassemble the Redmi Note 8T and replace the battery
Now, the most important step is to disassemble the phone, and it takes 30-60 minutes depending on the experience, and follow the instructions carefully so that you don't damage the plumes or the board.
Step 1: Removing the back cover
The Redmi Note 8T cover is glued around the perimeter, so it needs to be carefully heated. Use a dryer at minimum power (temperature ~60°C) or a thermo-air station. Warm up the edges of the case in a circle for 2-3 minutes, then:
- Insert a plastic mediator into the gap between the lid and the case (start at the lower corner where the SIM card is located).
- Carefully drive the mediator along the edge, separating the latches.
- Lift the lid - it should move away without resistance.
Step 2: Shutting off the battery
Once you remove the lid, you'll see the battery glued to the body, and first you'll need to disconnect it from the motherboard to avoid short circuits.
- Unscrew 4 screws that fix the metal plate over the battery plume (use the PH00 screwdriver).
- Carefully tuck the battery connector with a plastic spatula and disconnect it.
⚠️ Warning: If the battery is swelling, don't try to remove it by force, it can damage the board. Release the gas first, puncture the battery with protective gloves (only as a last resort!).
Step 3: Remove the old battery
The battery is glued to the body with double-sided tape to remove it.
- Put the battery in a plastic mediator from any angle.
- Pull slowly, applying the glue as you separate. If the resistance is strong, warm up with a dryer.
- Remove the residues of the glue from the case with alcohol or acetone (do not use solvents on plastic parts!).
Step 4: Installation of a new battery
Before installing, check the new battery for no defects.
- Remove the protective film with the adhesive side of the battery.
- Carefully press it to the body, starting with the connector.
- Connect the plume to the motherboard and fix the metal plate with screws.
Step 5: Assembly of the phone
Collect the phone in reverse order:
- Install the back cover, starting from the top (click carefully, without distortion).
- Warm up the edges with a hairdryer for better glue fixation.
- Put the screws in (do not pull!)
💡
If the phone doesn't turn on after assembly, check the battery plume connection and charging port contacts. A common mistake is incomplete connector fit.
What to do after replacement: calibration and testing
Replacing the battery is only half the battle, and in order for the new battery to work properly, it needs to be calibrated and tested.
1. First incorporation and verification
After assembly, connect the phone to charge and observe:
- 🔌 If the charging indicator is on fire, the battery is connected correctly.
- ⚡ If the phone doesn't turn on, try pinching Power + Volume up for 10 seconds (hard reset).
- 📉 If the charge drops too quickly, check the density of the battery to the housing.
Calibration of the battery
The new battery may be showing an incorrect percentage of charge.
- Charge your phone to 100% and keep charging for another 1-2 hours.
- Turn off the charging and discharge the phone until it automatically shuts down.
- Repeat the cycle 2-3 times.
You can also use the engineering menu to reset the battery data:
Enter the dialer: ##4636###
Go to "Battery Information" → "Reset Statistics"3. Capacity check
To make sure that the new battery meets the declared capacity, use the following applications:
- 📊 AccuBattery (shows real capacity and wear).
- 🔋 CPU-Z (Section "Battery" with voltage and temperature data).
⚠️ Warning: If the phone still runs out after calibration in 4-5 hours, there are two possible problems: a defective battery or high power consumption due to background processes. Check the application autoload in Settings → Applications → Auto Run.
What to do if the new battery does not hold the charge?
Common Mistakes and How to Avoid Them
Even with a careful battery replacement, beginners often make mistakes that lead to new problems, and here are the most common ones and ways to prevent them:
| Mistake. | Effects of consequences | How to avoid |
|---|---|---|
| Use of metal tools | Scratches on the body, damage to plumes | Use only plastic mediators. |
| Battery overheating with a hairdryer | Bloating or ignition | Keep the temperature below 60°C. |
| Incomplete battery shutdown before retrieval | Short circuit, board failure | Always remove the plume first thing. |
| Installation of a battery with a different capacity | Fast discharge, overheating. | Check the markings (should be 4000 mAh) |
| Strong tension of plumes during assembly | Contact break, broken screen | Lay the plumes without inflection |
Another common problem is that the phone doesn't see the new battery.
- 🔌 Bad contact - check if the connector is tightly inserted.
- 🔄 Power controller failure – reset via Fastboot (fastboot erase config).
- 📱 Firmware incompatibility – upgrade MIUI to the latest version.
If after replacement the battery is discharged overnight in standby mode, check the background processes:
- Go to Settings → Battery → Battery Use.
- Turn off auto-start for unnecessary applications.
- Activate the Energy Saving mode.
Where to buy a high-quality battery for Redmi Note 8T
The quality of the battery not only affects the life of the phone, but also its safety, cheap fakes can swell in a month or even ignite.
Official sources
- 🏬 Xiaomi service centers are original batteries with a warranty, but are more expensive by 30-50%.
- 🌍 Xiaomi’s official website (Accessory section) – sometimes there are sales.
2. Verified online stores
- 🛒 AliExpress – Look for sellers with a rating above 98% and reviews of durability.
- 🛒 Beru (formerly Yandex.Market) - there is a filter for original spare parts.
- 🛒 Wildberries – there are often stocks on batteries from Baseus or Remax.
3. Local services
In the big cities, there are phone parts stores (for example, Chip and Deep or Repair Center).
- ✅ You can check the battery before you buy it.
- ✅ There is no risk of losing the package.
- ✅ Often give a 1-3 month warranty.
Average battery prices for the Redmi Note 8T (June 2026):
- 🔋 Original - 1,800-2,500 rubles.
- 🔋 The qualitative analogue is 800-1 500 rubles.
- 🔋 B/w from disassembly - 500-1000 rubles (risky).
⚠️ Warning: When buying on AliExpress, pay attention to photos of the real product (not stock pictures) and ask the seller for quality certificates. Counterfeit products often have a capacity below the declared one (for example, 3000 mAh instead of 4000).