Xiaomi Redmi 3S is one of the most popular budget smartphones of 2016, which is still used by many users. However, after 7-8 years of operation, the original battery with a capacity of 4100 mAh inevitably loses up to 30-50% of its capacity: the phone discharges in a few hours, turns off at 20-30% charge or refuses to turn on. If you encounter these problems, replacing the battery is the only solution.
In this article, you will find detailed instructions on how to replace the battery with a Redmi 3S from the photo of each stage, recommendations for choosing a quality battery, as well as tips for extending its life after installation. We will understand what tools you need, how to safely disassemble the case, disconnect the plumes and connect the new battery without damaging the motherboard.
Important: the procedure requires precision and basic electronics skills, and if you've never taken a smartphone apart, you'd better go to a service center, but if you're willing to try, follow our guidelines.
Signs that the battery on the Redmi 3S is time to change
How do you know if the battery is the problem, not the software or the charger?
- 🔋 Phone's running out of power. 2-3 hours with moderate use (social networks, instant messengers).
- ⚡ Charging jumps: for example, with 50% drops 15%, or the phone is turned off when 20-30% charge.
- 🔌 When connected to a charge, Redmi 3S shows "Charging interrupted" or does not recognize the cable.
- 🌡️ The battery is swelling (visible from the raised screen or back cover).
- ⏳ The phone is slowly charging (more than 4-5 hours to 100%) or not charging at all.
If at least 2-3 items from the list are familiar, it is time to think about replacing. For accurate diagnosis, you can use applications like AccuBattery (showing real capacity) or CPU-Z (showing battery status in the Battery section).
⚠️ Warning: If the battery is swelling, immediately disconnect the phone from charging and do not use it until it is replaced!
It's also worth checking if there's any problem with the charger or cable.Try charging the Redmi 3S with another power supply (preferably original on the 5V/2A) and a USB Type-C cable. If symptoms persist, it's the battery's fault.
What battery to choose for Xiaomi Redmi 3S: original vs analogues
The original battery for the Redmi 3S is BM43 and has a capacity of 4100 mAh. However, it is almost impossible to find it on sale today - Xiaomi has long since withdrawn the model from production.
| Type of battery | Capacity | Pluses | Cons | Price (2026) |
|---|---|---|---|---|
| Original (b/u) | 4100 mAh | Perfect compatibility, long service life | Hard to find, risk of buying a fake, wear and tear | 1500–2500 ₽ |
| Analogue (quality) | 4000-4200 mAh | New, affordable, often with improved protection | It may be less than the original. | 800–1500 ₽ |
| Increased capacity | 5000–6,000 mAh | Holds the charge longer | The risk of overheating may not fit into the body | 1200–2000 ₽ |
We recommend to stop on high-quality analogues with a capacity of 4000-4200 mAh.
- 🔝 Baseus – reliable batteries with overheating protection.
- 🔝 Remax is a budget option with good reviews.
- 🔝 Patona is a German brand, 12 months warranty.
Avoid cheap no-name batteries (priced below 600 ₽) – they often have understated real capacity and can damage your phone.
- 📦 Presence of protective film on contacts (prevents short circuit).
- 🔍 Marking of BM43 or Redmi 3S on the housing.
- ⭐ Seller rating (not lower than 4.7) and reviews with photos.
Battery Replacement Tools: What You Need
To replace the battery with the Xiaomi Redmi 3S, you will need a minimum set of tools, most of which can be found in smartphone remakes (cost ~300-500 ₽) or buy separately:
- 🔧 Plastic blades (mediator) - to separate the housing.
- ✔️ Cross screwdriver (PH00) - for screws of the back cover.
- 🔥 Hair dryer or thermo-air station - for softening the glue.
- 🧲 Magnetic mat or tray - so as not to lose screws.
- 🔌 Tweezers - for careful disconnection of plumes.
- 📱 Suction (optional) - helps to tamper with the screen.
Also prepare:
- 📸 Smartphone for photos – fix every step so as not to confuse the order of assembly.
- 🧴 Isopropyl alcohol (90%+) — clean-up.
- 🧼 Wat or napkins without pile.
⚠️ Warning: Don't use metal blades or knives to disassemble! They can damage plumes or leave scratches on the body. Plastic mediators are safer.
If you don't have a hair dryer, you can do without it, but the process of removing the back cover will become more difficult - the glue on the Redmi 3S is quite durable. Alternative: heat the lid with hot water in the bag (carefully so that no moisture gets in!).
☑️ Preparation for battery replacement
Step-by-step: how to disassemble Xiaomi Redmi 3S and replace the battery
Now, to the most critical stage, disassembling the phone and replacing the battery, follow the instructions carefully so that no plumes or contacts are damaged.
Step 1: Turn off the phone and remove the back cover
1. Turn off Redmi 3S completely (press the power button and select Turn off).
2. Remove the tray for SIM-cards by means of a paper clip or a special key.
3. Heat the back cover with a hair dryer for 2-3 minutes (at ~60°C).This will soften the glue. Keep the hair dryer at a distance of 10-15 cm so as not to overheat the plastic.
4. Insert a plastic blade into the gap between the lid and the body (start at the lower right corner where the antenna is located). Carefully drive the blade around the perimeter, separating the lid.
⚠️ Don't put too much effort into it! If the lid doesn't lend itself, warm it up again with a hair dryer. On Redmi 3S the glue is particularly strong near the volume buttons.
Step 2: Disconnect the battery plume
1. Once you remove the lid, you'll see the battery glued to the body, and the motherboard is on the top, and the battery plume is on the right.
2 Carefully put a plastic blade on the black plume connector and unplug it from the board. Don't pull the wires!
3. Check the voltage at the battery contacts with a multimeter (should be ~3.7-4.2V).If the voltage is below 3.5V, the new battery may not be determined by the system.
What if the phone doesn’t turn on after the battery is disconnected?
Step 3: Remove the old battery
1. The battery is glued to the body with double-sided tape, put it in a plastic spatula from any angle, and slowly pull it up.
2 If the battery is not amenable, you can use isopropyl alcohol: drop a few drops under the battery - it will dissolve the glue.
3. Recycle old battery according to your region’s rules (don’t throw it away in the trash!).
Step 4: Installation of a new battery
1. Remove the protective film from the contacts of the new battery.
2. Carefully put the battery in place, combining contacts with the plume.
3. Connect the plume to the motherboard (it should be snapped with a slight click).
4. Press the battery against the body and check if it is not protruding above the level of the rear cover.
Step 5: Assembly of the phone
1. Make sure all plumes are connected and there are no foreign objects inside the enclosure.
2. Install the back cover in place, starting from the top (where the buttons are located).
3. Carefully press the perimeter lid. If it's not fixed, warm it up with a hair dryer and press it again.
4. Put the tray in. SIM-card and turn on the phone.
Is the battery plume connected correctly (sometimes it falls out when installing the lid).
- Are there any damages on the contacts (clean them with alcohol).
- Is the new battery sufficiently charged (plug in 10-15 minutes).-->
Calibration of the new battery: why it matters
After replacing the battery, it needs to be calibrated so that the charge controller correctly determines the level of charge. By skipping this step, you risk sudden phone shutdowns or incorrect display of interest.
Calibration instructions:
- Completely discharge the phone before automatically shutting down.
- Connect the original charger and charge up to 100% (without interrupting the process!).
- Turn off the charger and wait for full discharge again.
- Repeat the charging-discharge cycle 2-3 times.
We also recommend:
- 📱 Use the AccuBattery app to monitor battery status.
- 🔌 Charge the phone to 80-90% (rather than 100%) to extend its lifespan.
- 🌡️ Avoid overheating (do not play games while charging).
⚠️ Warning: If after calibration the phone still turns off at 20 to 30 percent charge, the problem may be the power controller on the motherboard, in which case a diagnosis will be required at the service center.
Common Mistakes When Replacing a Battery and How to Avoid Them
Even experienced users sometimes make mistakes that cause their phones to break down, and here are the most common ones and ways to prevent them:
| Mistake. | Effects of consequences | How to avoid |
|---|---|---|
| Use of metal tools | Damage to plumes, scratches on the body | Use only plastic shoulder blades |
| Hydrogen overheating | Deformation of plastic, detachment of plumes | Keep the hair dryer at a distance of 10-15 cm, the temperature is not higher than 60 ° C. |
| Unplug the battery plume without turning off the phone | Short circuit, failure of the power controller | Always turn off your phone before disassembling. |
| Installation of a battery with increased capacity without compatibility check | Overheating, bloating, body damage | Choose batteries with a capacity of no more than 4200 mAh |
Another common problem is that the phone doesn't turn on after the battery is replaced, and the reasons may be:
- 🔌 Unconnected battery plume (check connector).
- 🔋 New battery discharged (plug in 10-15 minutes of charging).
- 🛠️ Damage to the power controller (diagnosis required).
If you are sure everything is connected correctly but your phone is not responding, try:
- Connect the charger and hold the power button for 15-20 seconds.
- Try to turn on the phone without a battery (only connecting charging).
- Check the voltage at the battery contacts with a multimeter (should be ~3.7V).
💡
If the phone turns on after the battery is replaced but discharges quickly, most likely a problem with the quality of the new battery or its miscalibration. Try repeating the charging-discharge cycle 2-3 times.
How much does it cost to replace a battery in a service center vs on your own?
If you are not sure about your abilities, you can contact the service center.The cost of replacing the battery with the Xiaomi Redmi 3S in 2026 varies depending on the region and type of battery:
| Service | Cost (₽) | Time limit for implementation | Pluses | Cons |
|---|---|---|---|---|
| Replacement with analogue (4000 mAh) | 1200–1800 | 1-2 hours | 3-6 months warranty, quick repairs | The price is higher than with a self-replacement |
| Replacement with original (b/y) | 2000–3000 | 1-3 days | Reliability, long service life | Hard to find, high price |
| Self-sustaining replacement | 600-1500 (battery only) | 30-60 minutes | Savings, experience in repair | Risk of damage to the phone |
Should you save money and do it yourself? Decide from your experience:
- ✅ Self-substitution is beneficial if you’ve already disassembled smartphones or are confident in your skills.
- ❌ Contact the service if you have never dealt with microelectronics or are afraid of damaging your phone.
The average cost of a battery replacement service is 500-1000 ₽. So it's 30-50% cheaper to replace yourself, but remember, if you damage the plume or the motherboard, it can cost you 3,000-5000 ₽ to repair.