Xiaomi Mi 9 is fast discharged? 12 ways to extend the battery life

Xiaomi Mi 9, released 2019 The year, still remains a popular smartphone due to the powerful “iron” (Snapdragon processor). 855, 6/8 GB of RAM) and AMOLED-But many owners are facing a problem: the battery is on the screen. 3300 The scalp is too fast, especially after 2–3 years of use. What is the cause and how to eliminate it?

In this article - specific solutions tested on the Mi 9 with firmware MIUI 12-14 (including global and Chinese versions) We won't advise "turn off Bluetooth" or "reduce brightness" - these are the tips that are obvious. MIUI, hardware features of the model and software tricks that really affect autonomy.

Important: The Mi 9 has two key charge-eating weaknesses: the aggressive optimization of the Snapdragon 855 in the background and the power controller malfunction after long periods of use.

1. Disable "energy-intensive" functions MIUI, which you didn't know

Firmware MIUI It's the default service that uses energy all the time, and you can turn it off without losing functionality.

The first thing you need to do is to stop the auto-run of unnecessary applications, and even closed programs can wake up in the background and use up a charge.

1. Go to Settings → Applications → Application Management → Autorun.
2. Sort the list by the date of last use.
3. Turn off autoplay for all apps you use less than 1 time per week (e.g. Mi Video, Mi Browser, Games).

Second, limit your activity in the background for social media and instant messengers, which often update data even when you're not using it:

• 📱 Settings → Battery and productivity → Battery management → Select an app (such as Facebook) → Set up a “Limited Background Mode».
• 🔄 For Telegram and WhatsApp, it is enough to leave “Intelligent background mode” – this will save notifications, but reduce the cost.

Third, turn off Smart Assistance, which analyzes your actions and offers “helpful” clues, but constantly monitors your activity:

• 🤖 Go to Settings. → Special facilities → Smart Assistance.
• 🚫 Disable all items: “Hints”, “Automatic actions”, “Contextual prompts».

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If notifications from banking applications have stopped coming after autorun is turned off, add them to the exceptions in the Settings section. → Battery → Selection of applications (set "No restrictions»).

2. optimize the work of the Snapdragon 855 processor

Snapdragon 855 in Mi 9 is a powerful but voracious chip. MIUI It accelerates it even for simple tasks, which leads to overheating and rapid discharge.

Method 1: Enable Battery Mode (not to be confused with Charge Saving!):

• ⚡ Go to Settings. → Battery and productivity → Battery mode.
• 🔋 Choose Balanced or Economy (the latter is more performance-restricting but adds 15-20% autonomy).

Method 2: Limit the maximum core clock speed (requires root or engineering menus). If you don't have root rights, skip this. If you do, use Kernel Adiutor or FrancoKernel:

• 📉 Set the maximum frequency for large cores (Cortex-A76) at 2.42 GHz (instead of 2.84 GHz by default).
• 📉 For small kernels (Cortex-A55) limit to 1.8 GHz.

This will reduce performance in heavy gaming by 5-10%, but extend battery life by 25-30%, and for everyday tasks (social networks, instant messengers, video) it will not make a difference.

3.Tune in. AMOLED-low-flow screen

AMOLED-display 9 (6.39", 2340×1080) — One of the main advantages of the model, but also the main "eater" of charge, and you can optimize its operation through hidden settings.

Step 1: Turn on the dark theme and adaptive brightness:

• 🌑 Go to Settings. → Screen. → Dark theme and select "Always turn on." AMOLED This saves up to 30 percent of the charge.
• ☀️ Turn on Adaptive Brightness in the same section and calibrate it: in a dark room set the slider to 20-30%, on the street - no higher than 60%.

Step 2: Reduce screen resolution (does not affect visual quality, but reduces the load on the screen) GPU):

• 📏 Go to Settings. → Screen. → Screen resolution.
• 🔍 Choose. HD+ (1560×720) instead FHD+. The difference in the picture is minimal, and the battery will last on the 10–15% longer.

Step 3: Turn off the “Always on display» (AOD). This feature eats up to 5% charge per hour:

• 🕒 Go to Settings. → Screen locking → Always on display.
• 🚫 Turn off the function or set a timer for 10 seconds.

4. Check the battery health and reset the statistics

After 2-3 years of operation, the battery capacity of the Mi 9 drops by 20-40%. If the smartphone discharges in 3-4 hours with moderate use, the problem may be a degraded battery or a downed calibration of the power controller.

How to check the status of the battery:

1. Install the AccuBattery app (free version is enough).
2. Charge your smartphone to 100% and use it to 5%.
3. Check out the chart in the Health section: if the capacity is below 2500 mAh, it is time to change the battery.

If the capacity is normal (above 2800 mAh), but the smartphone still discharges quickly, reset the battery statistics:

• 🔄 Go to Settings. → Battery and productivity → Battery status.
• 📊 Click on three dots in the upper right corner → «Reset battery statistics».
• 🔋 Completely discharge the smartphone before turning off, then charge up to 100% without interruptions.

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If after resetting the statistics, the smartphone shows an incorrect percentage of charge (for example, jumps from 50% to 20%), repeat the procedure 2-3 times.

Battery replacement warning: On the Mi 9, the battery is soldered to the motherboard. Self-substitution without experience can damage the plumes or the charging controller. Only contact service centers with micro soldering equipment.

5. Disable unnecessary sensors and background processes

The Mi 9 is equipped with a variety of sensors (gyroscope, accelerometer, compass, barometer) that are constantly being surveyed by the system, many of which can be turned off without losing functionality.

What sensors can be safely turned off:

How to turn off background activity of system applications:

• 🛑 Go to Settings. → Annexes → Application management.
• 🔍 Find MiuiDaemon, Analytics, MSA (Mobile Security Agent).
• 🚫 For each of them, select “Stop» → «Shut down».

Open Task Manager (swipe up with retention)

Check if there are com.miui.analytics or com.xiaomi.midrop on the list

Close all unnecessary processes (except system ones)

Reboot your smartphone

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6. Optimize connections: mobile network, Wi-Fi, Bluetooth

Communications modules are another hidden source of consumption. On the Mi 9, mobile data is particularly voracious in mode. 4G+ and the constant search for Wi-Fi networks.

Setting up the mobile network:

• 📶 Go to Settings. → SIM-maps and mobile networks → Type of network.
• 🔄 Select Only. 4G (LTE) instead 4G+/5G (If your carrier does not support VoLTE, turn on the 3G call-in).
• 📡 Turn off the “Improving Call Quality” (VoLTE) if you are not using it. HD-ring-off.

Setting up Wi-Fi and Bluetooth:

• 📶 Enable the option to “Connect to Wi-Fi automatically” for home/work network only.
• 🔍 Turn off Device Search in Bluetooth settings if you don’t use wireless headphones.
• 🛡️ B Settings → Wi-Fi → Turn off Wi-Fi Direct and «WPS».

Hidden trick to save: If you rarely use mobile Internet, turn on the “Only” mode 2G» second SIM-If you have a card, it will reduce the cost by 7-10%.

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If the smartphone is quickly discharged in standby mode, check the settings MIUI Optimization in the Engineering Menu (#4636## → If there are processes with high Wake Lock, remove the relevant applications.

7 Hardware methods: what to do if the software does not help

If all of the above methods failed, the problem could be in the hardware: a worn-out battery, a damaged power controller, or an overheating chipset.

Signs of hardware problems:

• ⚡ Smartphone discharges by 10-15% per hour in standby mode.
• 🔥 The body heats up even with simple tasks.
• 🔋 When charging, the percentage of charge “jumps” (for example, from 80% to 50%).
• 🛑 The smartphone turns off at 20-30% charge.

What you can do on your own:

• 🔧 Replace the thermopaste on the processor. It dries over time, which leads to overheating and increased flow. MX-4 Or the Thermal Grizzly Kryonaut.
• 🔋 Check the battery contacts. Sometimes they oxidize, which leads to poor contact and quick discharge.
• 📡 Turn it off. 5G-Modem (if you have one in your Mi 9 version) to do this in the engineering menu (#4636##) select Phone Information → Set preferred network type → LTE only.

⚠️ Note: If you have no experience in disassembling smartphones, do not try to replace the heat paste or clean contacts yourself. contact the service center. Wrong actions can lead to short circuit or damage to the motherboard.

8. Alternative firmware: should you switch to caste?

If you have exhausted all the options of optimization on the standard MIUI, You can think of alternative firmware. Mi 9 works well:

• 🤖 LineageOS 20 (based on Android 13) – the most stable and economical.
• 📱 Pixel Experience – if you want a clean Android with a long update.
• ⚡ DerpFest – for balance between performance and autonomy.

The advantages of custom firmware:

• ✅ No unnecessary background processes MIUI.
• ✅ Best kernel optimization for Snapdragon 855.
• ✅ Ability to fine-tune processor frequencies.

Cons:

• ❌ Loss of the official guarantee if it is still valid).
• ❌ Risk of “bricking” when installed incorrectly.
• ❌ Some features (such as IR-blaster or Game Turbo) may not work.

If you decide to reflash, use the official TWRP for Mi 9 (cepheus) and make sure that the firmware is compatible with your model (M1902F1G — global, M1902F1T — China).

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Before the firmware be sure to make a backup through TWRP Or Mi Flash Tool. It's especially important to keep the persist partition containing data. IMEI and module calibration NFC.

FAQ: Frequent questions about the Xiaomi Mi battery 9