Xiaomi Mi 9T (He's a Redmi. K20 in China) – one of the most popular smartphones of the brand, released in 2019 A year later. 4-5 years of active use of its battery capacity 4000 mAh inevitably degrades: the phone discharges in half a day, turns off when 20-30% If you're facing these problems, it's time to think about replacing the battery.
But how much does it cost in 2026? Where do you change, whether it's in a service center, a private workshop, or on your own? And how do you avoid running into a fake that will last six months?
- 🔋 Real replacement prices in official and informal services (comparative table).
- 🛠️ Step-by-step instructions for self-replacement - with nuances for Mi 9T.
- ⚠️ Common Mistakes That Shorten the Life of a New Battery 2-3 once.
- 🔍 How to distinguish the original from the fake on 5 features (including the multimeter test).
Spoiler: the average cost of replacement in Russia varies from 1500 before 4500 But the final price depends on the type of battery, the region and even the payment method, and if you're willing to risk changing the battery yourself, you can do it. 800-1200 Roughly (but be prepared for surprises).
1.The cost of replacing the battery on Xiaomi Mi 9T 2026: Comparative table
Battery replacement prices vary depending on battery type, region and status of service center. Below are the current data for June 2026 for Russia, Ukraine, Kazakhstan and Belarus. Note: official Xiaomi services often use relabeled batteries from third-party manufacturers (for example, Desay or Sunwoda), passing them as “original”.
| Type of service | Type of battery | Price (₽/₴/₸/BYN) | Guarantee | Notes |
|---|---|---|---|---|
| Official Xiaomi service | "Original" (remarked) | 3500–4500 ₽ / 1800–2300 ₴ / 12 000–15 000 ₸ / 100–130 BYN | 6–12 months | They use Desay batteries or Sunwoda batteries with the Xiaomi logo, and they often refuse to put batteries purchased by a customer. |
| Authorized partner | Original (remainders) | 4000–5000 ₽ / 2000–2500 ₴ / 14 000–18 000 ₸ / 120–150 BYN | 12 months | Rarely are true originals with a production date of 2019-2020, the capacity may be lower than the declared. |
| Private workshop | Quality analogue (ZMI, Baseus) | 1500–2500 ₽ / 800–1300 ₴ / 6000–9000 ₸ / 50–80 BYN | 3–6 months | Best price/quality ratio, risk of getting a fake — ~20%. |
| Self-sustaining replacement | Analogue (AliExpress, Beru) | 800–1500 ₽ / 400–800 ₴ / 3000–6000 ₸ / 25–50 BYN | Depends on the seller. | Requires skills and tools. Risk of damage to the display plume — ~15%. |
⚠️ Attention: Moscow and St. Petersburg are 10-20% higher than the regions. < 200 thousand) the cost may be lower by 20-30%, but the risk of running into poor quality service is higher:
- 📅 Battery production date (originally indicated on sticker in format) YY/MM). If the battery is released earlier 2022 Years ago, its capacity has already been reduced.
- 🔄 Guarantee Policy: Some workshops give a guarantee only if their battery is installed.
- 🔧 Cost of work separately: in official services often "forget" to mention that the replacement take an additional 500-1000 rubles.
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Before replacing, check the actual capacity of the old battery with the application AccuBattery (Android).If it is below 60% of the original (2400 mAh instead of 4000 mAh), it is definitely time to change the battery.
2. Original vs analog: which battery to choose for Mi 9T?
The main question when replacing is what to put: the original battery (if it can still be found), the remarked "original" from the battery. Desay/Sunwoda Or a quality third-party model? Let's look at the pros and cons of each option.
🔹 The original Xiaomi battery (MBJ4057)
Pros:
- 🔋 Corresponds to factory parameters: capacity of 4000 mAh, voltage 3.85V.
- ⚡ Optimized for the Mi Power Controller 9T — less risk of overheating.
- 📅 12 months warranty (in official services).
Cons:
- 💸 Price 2-3 times higher than analogues (from 4000) ₽).
- 🔍 Hard to find: official deliveries stopped, only leftovers in warehouses.
- ⏳ Even the “new” original could lie in the warehouse for 3-4 years – the capacity has already been reduced by 10-15 years%.
🔹 Remarked "originals" (Desay, Sunwoda, ATL)
These are the same batteries that supplied components for Xiaomi, but with a brand label, often labeled as "official" in service centers.
Pros:
- 🔋 Quality close to the original (capacity 3800-4000 mAh).
- 💰 Cheaper than the original by 20-30%.
Cons:
- ⚠️ There is no guarantee that the battery is new - could re-add the sticker with the old one.
- 🔥 The risk of overheating is higher than that of the original (especially Sunwoda).
🔹 Qualitative analogues (ZMI, Baseus, Remax)
The best option is price/quality, the main thing is to choose a trusted seller (for example, AliExpress with a rating of 98%+).
Recommended models:
- 🔋 ZMI PBJ4057 — Capacity 4100 mAh, protection against overheating.
- 🔋 Baseus BJ-4000 — cheaper by 20%, but capacity 3900 mAh.
- 🔋 Remax RMB-J40 — Budgetary option (from 800) ₽), The guarantee is only 3 months.
How to verify the authenticity of the battery before buying?
3. Step-by-step instructions: how to replace the battery with Mi 9T independently
If you decide to replace yourself, prepare:
- 🔧 Plastic blades (for disassembly of the body).
- 🔥 Hair dryer or thermo-air station (for softening glue).
- ⚡ New battery (preferably with adhesive base).
- 🔌 Tap tape or bilateral scotch (for fixing plumes).
⚠️ Attention: In Xiaomi Mi 9T The battery is glued to the body with heat glue, not double-sided tape, as in newer models. If you do not remove it carefully, you can damage the plume of the display or the antenna module (located next to the battery).
Turn off the phone and remove it. SIM-map|Charge the battery to 30-50% (to avoid short circuits)|Prepare the workplace: clean surface, good lighting|Take a photo of the internal disassembly (useful when Assembly)|Disconnect your phone from all cables and accessories-->
Step 1: Removing the back cover
1. Heat the hair dryer edge of the back cover (temperature 60–70)°C) for 2-3 minutes.
2. insert a plastic blade into the gap between the lid and the body (start with the lower left corner where the SIM card is located).
3. Carefully swipe the perimeter, separating the glue. Don't force - the lid is held on the latches!
Step 2: Shutting off the battery
1. Unscrew 10 screws (Phillips #00 type) on a metal plate.
2. Unplug the battery plume with a plastic blade. Do not use metal tools - risk short circuit!
3. Put the battery on a special black tape (pull-tab) and slowly pull up. If the glue is too strong, warm up again with a hairdryer.
Step 3: Installation of a new battery
1. Remove the remnants of old glue from the case (isopropyl alcohol can be used).
2. glue the new battery to bilateral tape or heat glue (if the kit has adhesive base - just remove the protective film).
3. Connect the plume and assemble the phone in reverse sequence.
1. Correct connection of the battery plume.
2. Integrity of contacts on the motherboard (possibly oxidized).
3. charge the battery (plug in to the RAM for 30 minutes even if the indicator is not lit).-->
4.Typical battery replacement errors (and how to avoid them)
Even if you follow the instructions, there are nuances that are often forgotten. TOP-5 errors that cause a phone to break down or a new battery to deteriorate rapidly:
- Use of metal tools to detach the plume. → Risk: Short circuit, burnt motherboard. ✅ Solution: Use only plastic or wooden blades.
- Battery overheating with a hairdryer (above 80)°C). → Risk: Bloating or ignition of a lithium-ion battery. ✅ Solution: Keep the hair dryer at a distance of 5-10 cm and do not heat one point longer than 10 seconds.
- Installation of a battery without glue base. → Risk: the battery will "drive" inside the case, which will lead to a break in the plume. ✅ Solution: Use bilateral scotch 3M or special heat-glue for the battery.
- Incorrect calibration of the new battery. → Risk: The phone shows an incorrect percentage of charge (e.g., turns off at 30%). ✅ Solution: After replacement, completely discharge and charge the phone 2-3 times in a row.
- Buying a battery without voltage check. → Risk: Installation of a dead battery (voltage below) 3.5V). ✅ Solution: Check the voltage with the multimeter before installation (should be 3.8–3.9V).
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If after replacing the phone discharges quickly, check the background processes in the settings: → Battery → Battery use. Apps like Facebook or TikTok are often to blame, which consume even in the background.
5 Where to buy a battery for Xiaomi Mi 9T: vendor-tested
The choice of where to buy depends on your budget and willingness to take risks, and below is a ranking of reliable sources with pros and cons of each.
| Source | Average price | Pluses | Cons |
|---|---|---|---|
| AliExpress (Xiaomi Official Store, ZMI Flagship Store) | 800–1500 ₽ | ✅ Low prices✅ Wide selection of analogues | ❌ Long delivery (2-4 weeks)❌ Risk of counterfeiting (check reviews!) |
| Beru (Yandex Market) | 1200–2000 ₽ | ✅ Quick delivery (1-3 days)✅ Return within 14 days | ❌ Prices are higher than on AliExpress❌ Limited range |
| Local shops (for example, Svyaznoy, M. Video) | 2000–3000 ₽ | ✅ You can check before buying.✅ Shop guarantee | ❌ Relabeled batteries are often sold for the price of the original. |
| Groups in Telegram/VK (for example, @xiaomi_parts) | 1000–2500 ₽ | ✅ Prices below market✅ Opportunity to agree on verification | ❌ High risk of fraud❌ No guarantee |
⚠️ Note: Avoid shopping on Avito or OLX They often sell used batteries taken from other phones or fake AliExpress at an inflated price.
6. How to prolong the life of a new battery: 7 rules
Even the best battery will not last long if you do not follow the rules of operation. 9T:
- 🔋 Avoid full discharge. Lithium-ion batteries degrade faster if you regularly discharge them to 0%. Optimal range is 20 to 80%.
- ⚡ Don't use "fast charging" all the time. 9T chargeable 18W, But it heats up the battery. It's better to charge from the block for everyday use. 10W.
- 🌡️ Watch the temperature. If the phone heats up above 40.°C (for example, during games), remove the case and let it cool. High temperatures kill the capacity.
- 📵 Don't leave your phone on charge overnight after 100% Mi. 9T It keeps charging with microcurrents, which reduces battery life.
- 🔄 Calibrate the battery every 3 months. Completely discharge the phone before it turns off, then charge to 100% without interruptions.
- 🚫 Don't use cheap cables or charging. Bad cables cause power surges that spoil the battery. MTC-06).
- 📱 Update the firmware. In new versions. MIUI Optimized power consumption. Up-to-date firmware for Mi 9T — MIUI 14 based on Android 12.
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If you use wireless charging, remember: it heats the battery more than wired charging. 9T (where there is no native support Qi) it is especially harmful - the heat sink is worse than in flagships.