Replacing the battery with Xiaomi Mi 9: a complete guide with photos and videos

Why Xiaomi Mi 9 battery fails and when to change it

The Xiaomi Mi 9, released in 2019, is equipped with a 3300 mAh non-removable battery with Quick Charge 4+ fast charging support. Over time, even the original battery loses up to 30-40% of capacity after 2-3 years of active use. If your Mi 9 discharges in a few hours, turns off at 20-30% charge or overheats during charging, these are clear signs of battery wear.

The manufacturer claims a battery life of 500 full charging cycles, but in practice this figure depends on the operating conditions: frequent overheating, the use of non-original chargers or a discharge of up to 0% reduce the life of the Xiaomi Mi 9 after 2021 release often comes with controllers with updated firmware, which can cause conflict with the motherboard when replaced with non-original counterparts.

When is it time to change the battery?

• 🔋 Smartphone discharges in 3-4 hours with moderate use (social networks, instant messengers).
• 🔥 The body is noticeably heated in the battery area even without loading.
• ⚡ Charging is interrupted or is jerking (a sign of battery bloating).
• 📉 Settings menu → Battery condition is shown with capacity below 70%.

What tools will be needed to replace

To replace the battery on the Xiaomi Mi 9, you will need a specialized set of tools. Without them, the risk of damage to the plumes, display or battery itself increases significantly.

⚠️ Warning: Do not use metal blades or knives to tamper with the battery, this can break through the battery body and cause a short circuit. The best option is plastic mediators 0.2-0.3 mm thick.

If you are disassembling a smartphone for the first time, we recommend buying a battery replacement kit (cost) ~500–800 ₽), It's a bracelet that includes all the tools you need, and it's an antistatic bracelet (150-200). ₽), to avoid damage to the motherboard by static electricity.

Step-by-step: how to disassemble Xiaomi Mi 9

Disassembly Xiaomi Mi 9 requires care - inside the case are fragile plumes of the display and camera.

1. Turn off your smartphone and wait until it's completely cooled (if it's in use). SIM-paper-card.
2. Heat the back cover with a hair dryer (~60–70°C) for 2-3 minutes to soften the glue. Start at the bottom edge where the latches are located.
3. Insert a plastic mediator into the gap between the body and the screen at the Type-C connector. Carefully drive it along the perimeter, disconnecting the latches. Do not force - if the lid does not respond, warm it up again.
4. When you remove the lid, put it aside, and underneath it you'll see 20 screws (11 short and 9 long) -- remember their location or take a picture.
5. Unscrew all the screws with a T3 screwdriver and gently slap the battery plume with a plastic blade. Use tweezers to unplug the connector from the motherboard.

⚠️ Warning: Don't touch the contacts on the motherboard with your fingers, it can cause oxidation. If you notice signs of corrosion, clean them with an alcohol tampon.

At this point, the smartphone is completely de-energized, and you can start removing the old battery. If you are in doubt, stop here and contact the service center - further manipulation requires experience.

How to safely remove an old battery

The battery in Xiaomi Mi 9 is glued to the body with double-sided tape, which eventually becomes very sticky.

1. Apply a few drops of isopropyl alcohol under the battery from the connector side. Wait 1-2 minutes - the alcohol will dissolve the glue.
2. Put a plastic mediator on the battery and slowly pull it up, and if it doesn't respond, add alcohol and try again.
3. Don't pull the plume! If the battery is swollen, it can burst when you move abruptly, so put on your safety glasses and work with your gloves.

⚠️ Warning: If the battery is swelling (as seen from the deformation of the body), do not pierce it or bend it - this can lead to fire.

Once the battery is removed, clean the case with alcohol and a napkin without pile. Check the integrity of the flexible plume - if it is damaged, it will also have to be replaced (cost) ~300–500 ₽).

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If the adhesive is too strong, you can use a special adhesive remover for electronics (for example, Loctite 7360), which is safe for plastic and leaves no traces.

How to choose a new battery: original vs analogues

There are three types of batteries available for Xiaomi Mi 9:

• 🔝 Original (articles: MBJ4064) — factory-produced ATL Or Sunwoda, ordered by Xiaomi, with a capacity of 3300 mAh, 6-12 months warranty, price: 1,500-2,500 ₽.
• 🔄 Premium-class analogues (brands: ZMI, Baseus, Remax – often exceed the original in capacity (up to 3,500-3800 mAh), but may conflict with the charging controller. Price: 800-1 500 ₽.
• ⚠️ Budget analogues (no-name) – low price (300-600) ₽), But the risk of bloating or rapid wear and tear, often sold with understated real capacity.

How to distinguish the original from the fake?

• 🏭 The case must have a hologram Xiaomi and a serial number that matches the number on the package.
• 📦 Packaging - dense cardboard with the Mi logo, inside a protective film and instructions in Chinese.
• 🔍 The battery is indicated: Xiaomi Mi 9, 3.85V, 3300mAh, Date of production (not older than 1 year).

If you're looking for a similar one, look at the charging controller. Cheap batteries may not support Quick Charge 4+, which will make the smartphone charge slower. Also check for reviews about the particular model - some of the analogues warm up when used intensively.

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The optimal option for the ratio of price / quality - batteries ZMI or Baseus with a capacity of 3,500 mAh. They are cheaper than the original, but will last at least 2-3 years with proper operation.

Installation of a new battery and assembly of a smartphone

Before installing a new battery, check its voltage with a multimeter - it should be in the range of 3.7-3.85 V. If the voltage is below 3.5 V, the battery must be recharged with an external device (for example, iMax B6).

Step-by-step installation:

1. Remove the protective film from the new battery and glue it to double-sided tape (comes with the kit).
2. Connect the plume to the motherboard, make sure the connector is fixed before you click.
3. Lay the plume so that it does not overflex and does not touch the metal parts of the body.
4. Turn all the screws in reverse sequence. Don't pull them over, it could damage the thread.
5. Stick the back cover. Warm it up with a hair dryer (50°C) and press it for 1-2 minutes.

After assembly, turn on the smartphone and check:

• 🔋 Charge level (must match the real one).
• ⚡ Charging speed (at Quick Charge 4)+ I'm gonna need 30 minutes to get it. ~50%).
• 🌡️ Temperature of the shell (must not exceed 40)°C when charging).

If the smartphone is not turned on, check:

• The density of the battery plume.
• Integrity of contacts on the motherboard.
• Correct connection of the display plume (sometimes it falls out during assembly).

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After replacing the battery, calibrate the battery: fully discharge the smartphone before turning off, then charge to 100% without interruption. Repeat the procedure 2-3 times to accurately display the charge level.

Frequent Mistakes and How to Avoid Them

Even experienced tycoons sometimes make mistakes when replacing the battery, and here are the most common problems and solutions.

⚠️ Warning: If the battery is discharged in a few hours after the replacement and the smartphone is heated, this may indicate a short circuit inside the case!

Another common mistake is using superglue to fix the lid, which will make the next repair more difficult and can damage the plastic, and instead use 3M double-sided tape or special electronics glue (e.g. B-7000).

FAQ: Answers to popular questions