Why the Redmi Note 4X Battery Fails and When to Change It
Xiaomi Redmi Note 4X, released in 2017, is still popular due to its balanced performance and affordable price. However, even the most reliable device faces battery wear problems over time. On average, lithium polymer batteries lose up to 20-30% of capacity after 300-500 charging cycles, and after 2-3 years of active use their resource can be reduced by half.
How do you know it's time to replace your battery? The main signs are: fast discharge (the smartphone sits down in a few hours even in standby mode), sudden shutdowns at 20-30% charge, bloating (seen by the divergent seams or bulges of the screen), and overheating while charging. If you notice at least one of these symptoms, don't delay the replacement - a worn-out battery can damage other components of the phone.
In this article, you will find step-by-step instructions for replacing the Redmi Note 4X battery (model mido), tips for choosing a quality battery, as well as answers to frequent questions. We will consider both the option of disassembling the case yourself, and contacting the service center with the pros and cons of each approach.
What tools will be needed to replace
Before you start disassembling the Redmi Note 4X, prepare everything you need. Without the right tools, you risk damaging the plumes, the body, or even the battery itself.
- 🔧 Plastic mediators or shoulder blades (2-3 pcs. - for careful squeezing of the housing and disconnection of adhesive joints.
- ⚒️ Cross screwdriver (size PH00 or PH0) - for twisting the screws of the rear cover.
- 🔥 A dryer or thermo-air station to soften the adhesive that holds the battery.
- 🧲 Magnetic mat or container – so as not to lose small screws and parts.
- 🔋 New battery (original or quality analogue) - capacity of 4100 mAh, compatible with the mido model.
- 🧴 Isopropyl alcohol (90%+) — Cleaning contacts and removing glue residues.
- 🧤 Antistatic bracelet (optional) – protects components from static electricity.
If you are disassembling a smartphone for the first time, we recommend you to purchase a repair kit (sold on AliExpress or in electronics stores), which usually includes all the necessary mediators, suction cups and even a special glue to fix the new battery, the cost of this kit is from 300 to 800 rubles.
⚠️ Warning: Don't use metal tools (knives, screwdrivers) to smear the body! They can leave scratches on plastic or damage plumes. Plastic mediators are safer and more accurate.
How to choose a high-quality battery for Redmi Note 4X
The choice of battery not only affects battery life, but also the safety of your smartphone. Cheap, uncertified batteries can swell, overheat or even ignite.
- 🔍 Capacity: 4100 mAh (similar to the original) Batteries with declared capacity of 5000+ mAh are fake!
- 🏷️ Marking – The original battery must be marked with the model BM47, voltage 3.85V, production date.
- 🛡️ Certificates – Check for CE, RoHS or UL marks on the package.
- 📦 Package - the box must contain the battery itself, adhesive tape for fixing and instructions.
Where to buy? Best options:
| Source | Pluses | Cons | Average price |
|---|---|---|---|
| Official Xiaomi service | 100% original battery, warranty | Expensive, long (waiting for delivery) | 1 800–2 500 ₽ |
| AliExpress (stores with a rating of 98%+) | Low price, wide choice | Risk of getting a fake, long delivery | 600–1 200 ₽ |
| Local electronics stores | Quick purchase, can be checked before payment | Price higher than on AliExpress | 1 000–1 500 ₽ |
| Avito/Yula (with hands) | You can bargain, sometimes you get used to the originals. | High risk of counterfeiting, no guarantee | 400–900 ₽ |
If you've chosen to buy on AliExpress, look at the stores with a lot of reviews and photos of real customers. Good sellers often post videos of battery tests. From proven brands, you can recommend Baseus, Remax or Patona - they offer quality analogues of the original batteries.
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Before you buy, ask the seller to send you a photo of the battery with the label. The original always has a clear seal of the Xiaomi logo and a serial number.
Step-by-step instructions for replacing the battery
Now, to the process itself, the replacement time is about 30-60 minutes (depending on experience), and follow the instructions carefully so that you don't damage your smartphone.
Turn off the phone and remove it. SIM-memory-card|Charge your smartphone to at least 30% (in case you need to turn it on for inspection)|Prepare your workspace: a clean desk, good lighting, all tools at hand|Take photos of the case and location of the screws (in useful when Assembly)-->
Step 1: Removing the back cover
1. Turn off the Redmi Note 4X and place it down on a soft surface (such as a napkin).
2. Heat the back end of the hair dryer for 1-2 minutes. This will soften the glue. Don't overheat - the temperature should be comfortable for the hand (about 60 ° C).
3. Insert the plastic mediator into the gap between the body and the back cover (start at the bottom edge where the charging connector is located). Carefully drive the mediator around the perimeter, disconnecting the latches.
4 When the lid starts to move, don't pull it out, because there are plumes of the fingerprint scanner and antenna underneath, lift the lid and disconnect the plumes with a mediator.
Step 2: Disconnect the old battery
1. Unscrew all the screws that fix the metal plate above the battery (usually 8-10 pieces).
2. Carefully pluck the plate and remove it, and underneath it you'll see the battery connector, which is located at the top of the board.
3. Using a plastic mediator, disconnect the connector from the motherboard. You just need to slightly tamper with it on the side.
4. Check the voltage at the battery terminals with a multimeter (should be about 3.7-4.2V).If the voltage is below 3V, the battery is severely discharged and can be dangerous!
Step 3: Remove the old battery
1. The battery in the Redmi Note 4X is glued to the case. To remove it, reheat the battery surface with a hair dryer (no more than 1-2 minutes!).
2. Put a plastic blade on the battery from any end and slowly pull up. If the glue is too strong, use a thread or a guitar string: slide it under the battery and saw the glue back and forth.
3.Do not use metal tools to tamper with the battery - this may result in short circuit!
4. After removing the battery, clean the seat of the glue residue with isopropyl alcohol. Make sure that there is no debris or liquid on the board.
Step 4: Installation of a new battery
1. Remove the protective film from the new battery and make sure that the adhesive tape on it is intact.
2 Connect the new battery connector to the motherboard, make sure it sits tightly, without any distortions.
3. Carefully place the battery in place, starting at the bottom edge. Press it evenly so that the glue is grasped.
4. Install the metal plate back and twist all the screws (don't pull!).
Step 5: Assembly of the phone
1. Connect the fingerprint scanner and antenna plumes to the motherboard.
2. Place the back cover in place, starting at the top edge. Carefully press it around the perimeter so that the latches fall into place.
3. Turn on the phone and check:
- 🔋 Charging is normal (indicator shows an increase in percentages).
- 📶 The antenna is catching the network (no signal problem).
- 👆 The fingerprint scanner is working.
If everything is fine, congratulations, you have successfully replaced the battery.
⚠️ Warning: Once the battery is replaced, the smartphone may show the first 2-3 charge cycle incorrect percentage of charge. This is normal — the controller needs time to calibrate. Completely discharge and charge the phone 2-3 times in a row.
(1) The density of the battery connector to the motherboard.
(2) Integrity of plumes (especially fingerprint scanner).
3) Short circuit (try charging - if the phone is warm but not turned on, damage to the board is possible).-->
Frequent Mistakes and How to Avoid Them
Even experienced users sometimes make mistakes when replacing a battery, and here are the most common mistakes and ways to prevent them:
- 🔌 Trail damage -- occurs when you sloppyly remove the back cover. Always use plastic mediators and don't put too much effort into it.
- 🔥 Battery overheating - if you heat it with a hair dryer for too long, the battery can swell or ignite. Keep the hair dryer at a distance of 5-10 cm and don't point it at one point for longer than 30 seconds.
- 🔧 Loss of screws -- Redmi Note 4X has screws of different lengths, and if you mix them up, you can damage the board. Store them in a magnetic tagged container.
- 📉 Incorrect calibration — after you change the battery, the smartphone may show the wrong percentage of charge. To fix this, completely discharge and charge the phone 2-3 times.
- 🚫 Use non-original adhesive -- cheap adhesive can dissolve the plastic of the case or not hold the battery. Use only special double-sided tape for batteries.
If you do damage the plume or board, don't try to fix it yourself, go to the service center. The cost of repairing the plume of the fingerprint scanner, for example, will cost 800-1 500 rubles, which is cheaper than buying a new phone.
What to do if the battery is swelling?
Should I change the battery myself or contact the service?
Decide whether to replace the battery yourself or give the phone to the workshop, will help to compare the pros and cons of each option.
| Criteria | Self-sustaining replacement | Calling the service |
|---|---|---|
| Cost | 600–1,500 ₽ (parts only) | 1,500–3,000 ₽ (work of + spare parts) |
| Time. | 30-60 minutes | 1-3 days (depending on the service load) |
| Guarantee | No (if you damage your phone, repairs are at your expense) | Yes (usually 3-6 months to work) |
| Quality. | Depends on your skills and the battery you choose. | Professional work, but the risk of a divorce for unnecessary services |
| Difficulty | Medium (tools and accuracy needed) | Minimum (it is enough to bring a phone) |
A self-substitution is beneficial if:
- 💰 You are on a budget and willing to take risks.
- 🔧 You have experience disassembling the equipment (for example, you have already changed the screen or cleaned your laptop).
- ⏱️ You need to get your phone back to life immediately.
It is worth contacting the service if:
- 🛠️ You've never taken your smartphone apart and you're afraid of damaging something.
- 📱 Phone warranty (self-repair cancels it).
- 🔥 The battery swelled or damaged other components.
Average cost of battery replacement in service centers:
- Xiaomi’s official service is 2,000–2,500 ₽ (original battery).
- Local workshops – 1,200–1,800 ₽ (analogue + work).
- Communication salons (for example, the Messenger, MTS) – 1,500–2,200 ₽.
How to prolong the life of a new battery
To keep the new battery lasting as long as possible, follow these guidelines:
- 🔋 Avoid full discharge - charge the phone when the charge drops to 15-20%. Full discharge (0%) greatly reduces battery life.
- ⚡ Don't keep charging all the time -- turn off the cable after reaching 100%. Prolonged charging at full charge accelerates degradation.
- 🌡️ Watch the temperature – do not use your phone in the cold.-10°C and below) or in the heat (+40°C and above. Optimal temperature 10–35°C.
- 📵 Turn off unnecessary functions -- GPS, Bluetooth, mobile data in the background drains the battery. Turn them on only when necessary.
- 🔄 Calibrate the battery - once in a while 2-3 Fully unload and charge your phone for a month. 100% for the correct operation of the controller.
- 🛡️ Use original chargers – cheap cables and power supplies can damage the battery due to unstable voltage.
It’s also worth turning off MIUI optimization, which sometimes aggressively closes the background processes, but increases the load on the processor and, as a result, battery consumption. To do this, go to Settings → Battery and Performance → Power mode and choose Balanced instead of Economical.
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If you play games or watch videos frequently, reduce the screen refresh rate to 60Hz in the developer settings (Settings → About Phone → MIUI version – tap 7 times, then return to Additional → For Developers → Screen Update Frequency).