Why the Redmi 4X Battery Fails and When to Change It
Smartphone Xiaomi Redmi 4X (codenamed santoni) was released in 2017 and was equipped with a removable battery capacity of 4100 mAh. Even with careful use after 3-4 years, the original battery loses up to 30-40% of capacity: the phone discharges in a few hours, turns off at 20-30% charge or suddenly overheats. If you notice these symptoms, it’s time to think about replacing.
The manufacturer claims a battery life of 500-800 charge cycles, but in practice this figure depends on the operating conditions. Frequent overheating, using non-original chargers or storing a discharged phone on the shelf accelerates degradation. For example, if you leave the Redmi 4X on charge all night at temperatures above 25 ° C, the battery life is reduced by 20-30%.
How do you know if a battery needs to be replaced, not just calibrated?
- 🔋 The phone discharges from 100% to 0% in less than 6-8 hours with moderate use.
- 🔥 The body is noticeably heated in the battery area even without loading.
- ⚡ Charging is interrupted or jerked (for example, shows “100%”, and after a minute falls to 80%).
- 📉 Settings menu → Battery → The state of the battery capacity shows less than 3000 mAh.
Which battery to choose for Redmi 4X: original vs analogues
The original battery for the Redmi 4X has an MBJ416540 and a capacity of 4100 mAh. However, after 2020, Xiaomi officially stopped supplying spare parts for this model, so it is almost impossible to find a “native” battery.
- Original residues are sold under the Xiaomi or Mi brand, but often re-labeled counterparts. Price: 1500-2500 ₽.
- Lithium analogues from proven brands: Baseus, Remax, Patrona. Capacity is usually 4000-4200 mAh Price: 800-1500 ₽.
- No-name batteries without a brand (often with AliExpress) Risk of low quality and bloating. Price: 500-900 ₽.
When choosing, pay attention to:
- 🔍 Capacity: optimally 4000-4200 mAh Batteries at 5000 mAh and above may not fit into the case or overheat.
- 📏 Sizes: the original has dimensions 148 × 73 × 3,85 Even a minimal deviation will lead to installation problems.
- 🔌 Connector: Must be identical to the original (3 contacts) + thermistor).
- 🛡️ Protection: availability of charge/discharge controller and overheating protection.
| Brand | Capacity | Price (₽) | Pluses | Cons |
|---|---|---|---|---|
| Baseus | 4200 mAh | 1200–1500 | High quality, long service life | More expensive than analogues |
| Remax | 4000 mAh | 900–1200 | Good Price/Quality Relationship | Maybe a little bit different in size. |
| Patrona | 4100 mAh | 1000–1300 | Optimal capacity, reliable controller | Rarely available. |
| No-name (AliExpress) | 4,000-5,000 mAh | 500–900 | Low price | High risk of marriage, bloating, short service life |
⚠️ Warning: Buy batteries only from trusted sellers with a minimum 6-month warranty. Fake batteries can swell or ignite when charged. Check reviews before buying and ask the seller for a photo of the real product (not from the drain).
Battery Replacement Tools: What You Need
To replace your battery on a Redmi 4X, you'll need a minimum set of tools, and without them, you'll risk damaging the plumes, the case, or the battery itself.
- 🔧 Plastic mediators (2-3 pieces) - for careful lid slashing and battery disconnection.
- 🔨 The screwdriver (PH00 or PH0) — screw-off.
- 🧲 Magnetic mat or container – to avoid losing small details.
- 🔥 Dryer or thermo-air station - for softening the glue under the battery (optional).
- 🧴 Isopropyl alcohol (90%+) — Cleaning contacts and removing glue residues.
- 📦 New bilateral scotch or glue B7000 — battery-lock.
If you don't have a hair dryer, you can do without it, but it takes longer to remove the battery, and the alternative is to use a plastic card (like a bank card) to slowly tweak the battery, but this increases the risk of damage.
Buy a new battery with a reserve of capacity
Check the availability of all tools from the list
Discharge your phone to 20-30% for security
Prepare a clean, well-lit workplace
Take it off. SIM-card and memory card (if any)-->
⚠️ Warning: Never use metal tools (knives, screwdrivers) to smack the battery! This can short circuit and ignite. If the glue is too strong, it is better to warm the case with a hairdryer (maximum 60).°C) within 1-2 minutes.
Step-by-step: how to remove the old battery
Before starting work, be sure to turn off the phone and remove the tray for SIM-Follow the instructions:
- Removing the back cover: Insert the plastic mediator into the gap between the cover and the body (start at the lower right corner where the antenna is located). Carefully drive the instrument around the perimeter until the cover detachs. Be careful - under the lid there are plumes of the on button and the headphone socket.
- Spinning screws: With a PH00 screwdriver, unscrew all the screws (there are 12) and spread them out on a magnetic mat. Notice: screws of different lengths! Remember which one you were standing in, or take a picture.
- Disconnect the plumes: Carefully disable the motherboard, battery and camera plumes. Use a plastic mediator to keep the contacts in check. The battery plume is usually locked with a black latch -- pull it up.
- Removal of battery: If the battery is swelling, do not try to puncture or bend it - this can cause fire. Push the battery with a plastic card on the side and slowly pull up. If the glue is too strong, warm the body with a hairdryer (not higher than 60 ° C!) for 1-2 minutes.
After removing the battery, examine it for electrolyte swelling or leakage. If corrosion is visible on the motherboard contacts, clean them with a cotton swab dipped in isopropyl alcohol.
What to do if the battery is too tight?
Installation of a new battery and assembly of the phone
Before installing a new battery, check its voltage with a multimeter (should be 3.7-3.8 V). If the voltage is below 3.5 V, charge the battery with an external device to a safe level.
- Preparation of the seat: Remove the remnants of old glue from the body and battery compartment. Rub the surface with alcohol to avoid the scotch. If you use double-sided tape, cut it into strips and paste it on the body (not on the battery!).
- Battery connection: Carefully connect the new battery plume to the motherboard. Make sure the contacts match and the latch is secure. Don't make any effort -- if the plume doesn't come in, check its orientation.
- Battery fixation: Put the battery back in place and press it slightly to make it stick. Don't push too hard, it can warp the cells. If you use B7000 glue, apply it point-by-point in the corners and let it dry for 5-10 minutes.
- Phone assembly: Reconnect all the plumes in reverse order, twist the screws (watch their length!) and snap the back cover. It should stand in place with a slight click.
Don't turn the phone on immediately after assembly. Wait 10-15 minutes for glue or tape to securely lock the battery. Then plug the charger in and watch the charging process for 30 minutes -- there should be no overheating or spikes in percentage.
1. Correct connection of the battery plume.
2. the presence of voltage on the contacts (multimeter).
3. Integrity of the fuse on the motherboard (often burns out with KZ).-->
Calibration of the new battery: why it matters
The new battery requires calibration so that the charge controller can correctly determine its capacity, without which the phone can show the wrong percentage of charge or suddenly turn off.
- First cycle: Charge the phone to 100% and leave on charging for another 1-2 hours. Then discharge until automatically turned off (0%).
- Second cycle: Recharge to 100% and discharge again before shutting down, at which point the controller remembers the actual capacity.
- Cycle three: Charge the phone to 100% and use it as normal. After that, calibration is complete.
To speed up the process, you can use the Xiaomi engineering menu:
- Enter the dialer code ##4636##.
- Go to the Battery Information section.
- Check the Battery Health option – after calibration, it should show “Good.”
⚠️ Warning: Do not use utilities to "reset battery statistics" (e.g. via adb). 4X This can cause the charge controller to crash and the phone to completely discharge in a few minutes.
💡
The new battery takes 2-3 full charge/discharge cycles to calibrate, and without it, the phone will be showing the wrong percentage of charge and may suddenly turn off.
Frequent Mistakes and How to Avoid Them
Even with a careful battery replacement, users often face problems, and here are the most common mistakes and ways to prevent them:
| Mistake. | Reason. | How to avoid |
|---|---|---|
| The phone will not turn on after assembly. | Unconnected battery or motherboard plume | Check all contacts, especially the battery latch |
| Fast discharge of the new battery | Poor battery or lack of calibration | Buy batteries from proven brands and run 2-3 calibration cycles |
| Overheating of the phone when charging | Poor plume contact or battery defect | Clean the contacts with alcohol and check the voltage with a multimeter |
| Battery Bloating in 1-2 Months | Using a no-name battery without protection | Choose batteries with a charge/discharge controller |
If your phone is running slower or overheating after replacement, check:
- 🔌 Charger – Use the original Xiaomi adapter (5V/2A).
- 📱 Background applications – some programs (such as messengers) can drain the battery.
- 🔄 Software updates – outdated firmware may conflict with new battery.