Xiaomi Mi 9 SE — compact 2019 It's a year that's still popular today because of its balanced characteristics and its convenient size. 3-4 During the year of active use, even the best battery loses 30-40% It's a capacity that causes quick discharge, spontaneous reboots, and charging problems, if your smartphone starts to turn off when you're on a powered device. 20-30% Recharge or recharge several times a day – it’s time to think about replacing the battery.
In this article you will find step-by-step instructions for replacing the battery with Mi. 9 SE So we'll take all the nuances from choosing the original battery to calibrating it properly after installation, and we'll look at what tools you need, how to avoid disassembly errors, and what to do if you don't turn on after you replace it. You will also find out whether to contact the service center or you can cope independently - saving up to 5000-7000 RUB (average replacement cost in workshops on the 2026 year).
Signs that the Xiaomi Mi 9 battery SE change
It's not always a quick battery drain that means it's going to fail, and sometimes it's software failures or application background activity, but there are some clear symptoms that indicate that the battery is wearing out physically.
- 🔋 The smartphone is turned off when 20-30% Charge, although the settings show a normal level.
- ⚡ The battery is discharged on 10-15% post 10-15 minutes without active use (e.g., in standby mode).
- 🔌 Charging is jerky: it quickly gains interest, then “freezes” at one level.
- 🌡️ The case of the smartphone is very hot when charging or under load (even if it was not before).
- 📉 The Autonomous Work Time has been reduced in 2-3 compared to the new device.
- 🔄 After the charging is turned off, the battery level “jumps” (for example, from 100% immediately to 85%).
If you're watching at least 2-3 the list of signs - the probability of battery wear is 90%. To make sure you’re sure, check the battery status through an engineering menu or apps like AccuBattery (available on Google Play). 70%, replacement should not be postponed.
⚠️ Warning: If the battery is swollen (the case of the smartphone began to “spark” or there were gaps between the screen and the frame) – immediately turn off the device and do not try to charge it.
What battery to choose for Xiaomi Mi 9 SE: original vs analogue
Original battery for the Mi 9 SE markable BM47 (or BM48 In some batches, there's a nominal capacity of 3070 mAh. But there are many different models on the market that vary in price, quality and durability:
| Type of battery | Capacity | Average price (2026) | Pluses | Cons |
|---|---|---|---|---|
| The original (Xiaomi) | 3070 mAh | 2500–3500 ₽ | Guaranteed compatibility, long service life, minimal risk of bloating | High price, hard to find in retail (often fakes) |
| Analogue (quality) (e.g. Baseus, Remax) | 3000–3200 mAh | 1200–1800 ₽ | Good quality/price ratio, easy to buy | Can serve on 20-30% less than the original |
| Budgetary analogue (no-name brands) | 2800-3000 mAh | 600–1000 ₽ | Low price | High risk of bloating, rapid degradation, possible charging problems |
| Increased capacity (for example, 4000 mAh) | 3,500 to 4,000 mAh | 2000–3000 ₽ | Holds the charge longer | May not fit into the case, overheating, risk of damage to the charging controller |
We recommend choosing between the original battery (if you find it with a warranty) or the quality of the proven brands. Avoid batteries with overcapacity, which often do not meet the declared characteristics and can damage the power bill.
- 📦 Packaging: Original must have hologram, serial number and Xiaomi marking.
- 🔍 Contacts: The battery should not be oxidized or damaged.
- 📄 Documents: Check for a check or warranty card (especially when buying from online stores).
Where to buy it?
- 🛒 Xiaomi's official stores (if available).
- 🌍 AliExpress (look for sellers with a rating above 98% and reviews in Russian).
- 🏬 Local parts stores (e.g. Fix Price Repair, Chip and Deep).
⚠️ Note: If you buy a battery on AliExpress, choose options with delivery from Russian warehouses - this will reduce the waiting time to the maximum. 5-10 days 1-2 months when shipping from China.
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Before buying, check the battery serial number through Mi Verify (if the seller provided a photo of the package).
Preparing for replacement: security tools and measures
Replacement of the battery with Xiaomi Mi 9 SE It requires precision and the right tools. Unlike the replacement batteries in older smartphones, you have to take the device apart completely, and you can risk damaging the plumes or the display:
Screen suction cup (∅ 5-7 cm)
Plastic blades (mediator) - 2-3 pieces.
Screwdriver cross (PH00 or PH0)
Screwdriver flat (1-1.5 mm)
Tweezers (preferably magnetic)
Thermoclee or bilateral scotch (for fixing a new battery)
Isopropyl alcohol (90%+) and cotton swabs
Fryer (for softening glue)
Antistatic bracelet (optional, but recommended)-->
Also prepare the workplace:
- 🪑 Work at a table with good lighting (better to use a desk lamp).
- 🧲 Remove all metal objects that may be magnetized to the screwdriver.
- 📱 Place your smartphone on a soft surface (such as a napkin) so as not to scratch the body.
Security measures:
- 🔌 Turn off your smartphone and wait until it is completely discharged (up to 0.
- 🔥 Do not use metal tools to tamper with the battery - only plastic blades!
- 🧤 If the battery is swollen, do not try to pierce or bend it - this can lead to fire.
- 🚫 Do not disassemble your smartphone in high humidity (for example, in the bathroom).
If you’ve never disassembled a smartphone before, practice on an old device or watch video guides for disassembling the Mi 9 SE (For example, on Fixez or Repair Universe, pay attention to the moments:
- 🔧 How to properly tuck the screen so as not to damage the plumes.
- 🔋 How to disconnect the battery from the board (usually there is a special connector).
- 📱 How to remove the back cover without breaking the latches.
What to do if the screen is too tight?
Step-by-step instructions for replacing the battery
Now, let's get to the process. Follow the instructions carefully, because one mistake can knock your smartphone out!
Step 1: Removing the back cover
1. Turn off the Mi 9. SE and remove the tray for SIM-map.
2. warm up the hair dryer edge of the back cover (especially near the buttons and camera) for 30–60 seconds.
3. With a suction cup, gently pull the lid up. If it doesn't respond, repeat the warm-up.
4 When a gap appears, insert a plastic shoulder blade and slowly guide it around the perimeter, snapping the clamps.
Step 2: Disconnecting the plumes
1 Unscrew 6 screws that fix the metal plate above the battery (use the PH00 screwdriver).
2. Carefully remove the plate and put it aside (do not lose screws!).
3. Disconnect the battery connector from the motherboard with a plastic blade. Don't pull the wires!
Step 3: Remove the old battery
1. Put a plastic blade on the battery from any angle. If it's glued heavily, drop some isopropyl alcohol under it (it dissolves the glue).
2. Slowly separate the battery from the body, putting it around the perimeter.
3. When the battery is almost separated, disconnect the remaining wires (if any).
Step 4: Installation of a new battery
1. Remove the protective film from the new battery and glue it to bilateral tape or heat glue.
2. Connect the connector to the motherboard. Make sure the contacts match!
3. Secure the metal plate and twist the screws (do not tug!).
Step 5: Build a Smartphone
1. Connect the tailgates of the back cover (cameras, fingerprint scanner, etc.).
2. Set the lid in place and snap it, starting at the bottom.
3. Insert the tray for SIM-maps and switch on the device.
If after assembly the smartphone does not turn on:
- 🔌 Check if the battery connector is tightly connected.
- 🔧 Make sure all the sleeves are connected correctly.
- 🔋 Try charging the device for 10-15 minutes – the new battery may be discharged.
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If the battery is discharged too quickly after replacement, calibrate (described in the next section).
Calibration of the battery after replacement
The new battery needs to be calibrated correctly so that the charging controller can accurately determine its capacity, without which the smartphone can show the wrong level of charge or turn off prematurely.
- Use your smartphone before you turn off automatically (do not charge even if a low charge warning appears!).
- Charge to 100%: Connect the original charger and wait for 100%.
- Additional charging: After reaching 100%, leave your smartphone on charging for another 1-2 hours.
- Recycle: Discharge the device to 0% and charge again to 100%.
This procedure is recommended to be repeated 2-3 times in the first days after replacement.
- 📵 Disable battery optimization for critical applications (in Battery settings) → Optimizing the battery).
- 🔄 Reset battery statistics via the engineering menu (code ##4636##, section Battery Information).
- 📊 Install AccuBattery app to monitor status of new battery.
After calibration, the battery should return to factory performance (using the original battery).
- 🔍 Background activity of applications (in the Battery settings) → Battery utilization).
- 📶 Network signal quality – weak signal increases charge consumption.
- 🔄 Software updates – sometimes firmware bugs lead to increased power consumption.
Frequent Mistakes and How to Avoid Them
Even experienced tycoons sometimes make mistakes when replacing a battery, and here are the most common problems and ways to prevent them:
| Mistake. | Effects of consequences | How to avoid |
|---|---|---|
| Use of metal tools to tamper with battery | Short circuit, board break, fire | Use only plastic shoulder blades or mediators |
| Dryer overheating | Bloating or ignition of the battery | Keep the hair dryer at a distance of 10-15 cm, the temperature is not higher than 60 ° C. |
| Incomplete shutdown of plumes before removing the battery | Damage to connectors, failure of the camera or display | Take a photo of the location of the plumes before disconnecting |
| Using poor quality glue for fixation | The battery will fall off, there may be problems with vibration | Use heat-glue or original bilateral Scotch |
| Connecting a new battery with reverse polarity | Instant failure of the power controller | Check the markings on the board (+ and –) |
If you have problems after your replacement, don't panic. Here's what to do in typical situations:
- 🔌 Smartphone won't turn on: Check the battery connector connection. Connect the charger for 10-15 minutes, the new battery may be discharged. If it doesn't work, the power plume may have been damaged (diagnosis needed).
- 📉 Fast discharge: Calibrate (described above) and check if there is a non-original battery with low capacity.
- 🔥 Overheating: Make sure the battery is not swelling (check visually). Turn off fast charging in settings (Settings) → Battery → Fast charging).
⚠️ Note: If after replacing the battery, the smartphone began spontaneously restarting or turning off when 50-60% The charge is probably a problem with the motherboard's power controller, and it's going to require professional repairs.
Should I change the battery myself or contact the service?
The decision depends on your experience, the tools available and the willingness to take risks. Let's compare the pros and cons of both options:
| Criteria | Self-sustaining replacement | Calling the service |
|---|---|---|
| Cost | 1200–3500 ₽ (just a spare part) | 3000–7000 ₽ (spare + job) |
| Time. | 1-2 hours (if you have experience) | 1-3 days (depending on the workload) |
| Guarantee | No (if you hurt something yourself) | Yes (usually 1-3 months to work) |
| Risks. | Damage to plumes, display, boards | Minimum (when choosing a verified service) |
| Quality of work | Depends on your accuracy. | Professional assembly, checking for leakage |
When to contact the service:
- 🛠️ You have no experience in disassembling smartphones.
- 🔧 You are afraid of damaging plumes or displays.
- 🔋 The battery is swelling - its removal requires special care.
- ⚡ After self-replacement, problems arose (does not turn on, warms, etc.).
When you can manage on your own:
- 🔧 You have the tools and patience you need.
- 📺 You have watched a few video instructions and are confident in your abilities.
- 💰 Want to save money (the difference in price can reach 4000-5000) ₽).
If you decide to use the service, choose proven workshops with good reviews.
- 📄 Availability of a work guarantee (minimum 1 month).
- 🔧 Parts used (ask, original or analogue).
- ⭐ Rating on Yandex.Maps or 2GIS (not lower than 4.5).
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If you live in a small town that doesn’t have Xiaomi repair services, consider sending your smartphone to a service center by mail (many companies offer this service).