Why choosing a battery for the Redmi Note 7 is a responsible decision
The Xiaomi Redmi Note 7, launched in 2019, is still popular with users due to its balanced specs and affordable price, but over time, even the most reliable gadget begins to lose battery capacity: the phone runs out in a few hours, turns off at 20-30% charge or requires constant recharging. If you are faced with these problems, it’s time to think about replacing the battery.
But how to choose the right battery among dozens of offers on the market? The original part from Xiaomi will cost more, but guarantees compatibility and safety, and counterparts from third-party manufacturers (for example, ZMI, Baseus or Remax) can save money, but do not always meet the declared characteristics. In this article, we will analyze all the criteria for choosing, from technical parameters to installation nuances, and also give practical tips on how to extend the life of a new battery.
We will focus on the risks of buying fake batteries – up to 40% of the Redmi Note 7 batteries on the market do not meet the original specifications, which can lead to bloating, overheating or even fire. To avoid these problems, we have compiled a checklist and a comparison table of reliable suppliers.
Technical characteristics of the original battery
Before you buy a replacement, check out the battery options of Xiaomi Redmi Note 7:
- 🔋 Capacity: 4000 mAh (minimum allowable capacity of the new battery is 3900 mAh).
- 🔌 Type: Li-Polymer (lithium polymer), incompatible with Li-Ion!
- 📏 Sizes: ~154 × 73 × 3,5 mm (exact dimensions depend on lot).
- ⚡ Voltage: 3.85 V (nominal), 4.4 V (maximum).
- 🆔 Original article: MB-J20 (supplant 4/64 GB MB-J21 (for 3/32 GB).
Importantly, even Xiaomi’s original batteries can have minor marking differences (e.g., the MB-J20BR for the Brazilian market), but the main thing is the coincidence of capacity, voltage and physical dimensions. If you buy an analog, check for CE and RoHS certificates, which confirm the safety of the battery.
⚠️ Warning: Batteries with a capacity above 4000 mAh (e.g. 4500 mAh or 5000 mAh) are not "improved" versions! They often have an understated real capacity or incorrectly display the charge level in the system. The Redmi Note 7 charging controller is not optimized for such batteries.
Original vs Analogues: Pros and Cons
The choice between the original battery and the analogue depends on the budget and reliability requirements.
| Criteria | Original battery | Quality analogue | Budgetary analogue |
|---|---|---|---|
| Term of service | 3–4 years (500–600 cycles) | 2–3 years (400–500 cycles) | 1-2 years (200-300 cycles) |
| Compatibility | 100% (proper operation of sensors) | 95-99% (may have minor errors) | 70–90% (Risk of Charging Errors) |
| Price (2026) | 1 800–2 500 ₽ | 1 200–1 800 ₽ | 500–1 200 ₽ |
| Guarantee | 6–12 months | 3–6 months | Absent or 1 month |
Original batteries are supplied in branded packaging with a hologram and QR-Analogues from trusted brands (e.g. Baseus) BIPP or ZMI PowerPacks are often equipped with additional accessories such as a glue for fixing or a plastic mediator to open the case.
Budget analogues (without brand indication) may have:
- 🔴 Low real capacity (for example, instead of 4000 mAh – 3200 mAh).
- 🔴 Lack of protection against overheating or short circuit.
- 🔴 Inconsistency of the connector (may require soldering).
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Before buying a battery, check the reviews on the marketplace with photos of the actual battery. Pay attention to the weight: the original battery weighs ~45-50 g, and counterfeits are often lighter due to the simplified design.
Where to buy a battery for Redmi Note 7: proven sources
Avoid shopping at dubious sites like Avito or Yula, the risk of running into used or fake batteries is too high.
- 🛒 Official partners of Xiaomi: Mi Store, Svyaznoy, M. Video (guarantee of authenticity).
- 🌍 Global marketplaces: AliExpress (shops rated 98%+), Amazon (Sellers with Certificate) FBA).
- 🔧 Service centers: Contact an authorized Xiaomi SCC – they often sell original parts separately.
- 📦 Specialty stores: BatteryShop, AkkuMarket (there are battery tests on YouTube).
When buying on AliExpress, pay attention to the following details:
- 📌 Availability of a photo of a real product (not stock pictures).
- 📌 Description of the exact item (e.g, MB-J20).
- 📌 Reviews with photos of packaging and battery after installation.
⚠️ Attention: AliExpress often has "improved" batteries with a capacity of 5000 mAh or 6000 mAh. This is a scam: the controller Redmi Note 7 does not physically support such batteries.
Step-by-step instructions for replacing the battery
If you decide to replace the battery yourself, follow this instruction: ~30-40 minutes. Complexity: medium (needs accuracy).
Purchased battery (check compatibility)|Plastic mediator or guitar mediator|Cross screwdriver (size) PH00)|Tweezers|Double-sided tape or glue B-7000|Fryer (for softening glue)|Alcohol wipes (for cleaning contacts)-->
Step 1 Turn off the phone and remove it. SIM-map.
Completely discharge the smartphone (before you turn off automatically), then wait 10-15 minutes. This minimizes the risk of short circuit. SIM-paper-card.
Step 2. Heat the back cover with a hair dryer.
The Redmi Note 7 case is glued around the perimeter. Heat the edges with a hair dryer (temperature). ~60–70°C) for 2-3 minutes to soften the glue. Do not overheat - plastic may deform!
Step 3. Carefully lid the mediator.
Start at the bottom left corner (near the USB-C connector). Put the mediator in the slot and slowly lead along the edge, separating the lid. If you feel resistance, warm up the place again with a hairdryer.
Step 4. Disconnect the battery plume.
When you remove the lid, you'll see the battery glued to the body, and the first thing you do is unplug the power plume (which is located at the top of the battery, under the black safety tape), and use tweezers to gently lift the connector.
What to do if the plume is glued to the battery?
Step 5. Remove the old battery.
The battery is glued to the body with double-sided tape, put it on either side and slowly pull it up. If the battery is swelling, don't pierce it, it can cause fire! Use alcohol wipes to clear the case of glue residue.
Step 6. Install a new battery.
Make sure the new battery contacts match the socket on the board, paste it with double-sided tape (which comes with the kit), or apply a thin layer of B-7000 glue, connect the plume and check the phone before the case is assembled!
Step 7, get your phone together.
Make sure all the plumes are connected, then press the back cover. To securely fix, warm the edges with a hairdryer (to make the glue better grasp) and place the phone under a press (for example, a stack of books) for 10-15 minutes.
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After replacing the battery, be sure to calibrate: completely discharge the phone, then charge to 100% without interruption. Repeat the procedure 2-3 times to accurately display the charge level.
How to prolong the life of a new battery
Even the original battery will last longer if you follow these rules:
- 🔄 Avoid full discharge: optimal charge range is 20-80%. Regular discharges up to 0% reduce the life of the battery.
- ⚡ Use the original RAM: Xiaomi charger with Quick Charge 4.0 support (power 18W) will provide the correct current.
- 🌡️ Control the temperature: Do not leave your phone in the sun or near heat sources. The optimum operating temperature is 10-35.°C.
- 📵 Disable unnecessary functions: GPS, NFC Background synchronization increases energy consumption.
- 🔋 Store it correctly: If you don’t use your phone for long, charge it up to 50% and turn it off.
In the settings of Redmi Note 7 there is a hidden function of battery optimization:
- Go to Settings → Battery and Performance → Battery Settings
- Activate the option "Adaptive Charging" (if available after the MIUI 12+ update).
- Enable Background Limitation for energy-intensive apps (like Facebook or Instagram).
⚠️ Warning: If after the battery change, the phone starts to overheat or discharge quickly, check: Correct connection of the plume (possibly contact has gone away). MIUI (In new versions, power management errors have been corrected. USB-C (Frequent replacement errors and how to avoid them Even experienced users make mistakes that cause their phone to break down or the battery to fail quickly. Using metal tools (screwdriver, knife) to open the case, it scratches the plastic and can damage the plumes. Solution: use only plastic mediators, overheat the battery with a hairdryer, temperatures above 80°C destroys lithium polymer cells. Solution: Keep the hair dryer 10 to 15 cm away and heat for no longer than 3 minutes. Superglue battery glue. It can leak to the contacts and cause a short circuit. Solution: use double-sided tape or glue. B-7000. Ignoring calibration. Once replaced, the phone may show the wrong percentage of charge. Solution: run 2-3 full-discharge/charging cycles. Buy a battery without protection. Cheap counterparts often lack a controller to prevent recharging. Solution: check for labeling PCM (Protection Circuit Module on the battery, if the phone doesn't turn on after the replacement, don't panic: 🔌 Battery plume not connected → Check the contacts. 🔋 New battery discharged → Connect the charger for 10-15 minutes. 📱 Short circuit protection worked → Disconnect the battery for 1 minute and plug it back in again. FAQ: Can you use the battery from the Redmi Note 7 Pro in the usual Redmi Note 7? No, despite the similar names, the Redmi Note 7 Pro has a battery with a different connector and capacity (4000 mAh vs 4000 mAh, but different wiring) Installing such a battery will lead to charging errors or a failure of the controller. How to check the originality of the battery before buying? Original Xiaomi battery has: Hologram on the package with QR-code (checked through the Mi Verify app) MB-J20 or MB-J21 The weight of the battery. ~45-50 g (fakes are often easier) Factory tape on the contacts. Also ask the seller for a photo of the battery on either side - there are no traces of soldering or uneven seams on the original. How much does it cost to replace the battery in the service center? The cost of replacing the battery in the authorized Xiaomi SC (2026): Original battery + work: 2,500–3,500 ₽. Analogue + work: 1,500–2,500 ₽. In informal workshops, the price may be lower, but the risk of installing a poor-quality battery is higher. Always ask for a work warranty (at least 3 months). What to do if a new battery is quickly discharged? Causes and solutions: Poor battery → Return it to the seller under warranty. Background processes → Check battery consumption in Settings → Battery and turn off energy-intensive applications. Faulty charging controller → Diagnosing in the SC. Calibration is not performed → Conduct 2-3 cycles of full discharge / charging. Can you replace the battery without special tools? Technically, but the risk of damaging the phone is extremely high. Without a plastic media and a hairdress, you can apply to the battery, or the battery deheater.