Xiaomi Redmi 9 is one of the most popular budget smartphones, but not everyone knows that it supports fast charging technology (although not the most advanced version). By default, the feature can be turned off or not work at full power due to power saving settings. In this article, we will discuss how to activate accelerated charging correctly, which chargers are suitable, and why sometimes the smartphone “fails” to charge faster.
It’s important to understand that the Redmi 9 is equipped with Quick Charge 3.0 support (up to 18 watts), but comes with a standard 10 watt charger. This means that for a full fast charging you will need to buy a compatible adapter. We will tell you how to check the current charging mode, turn it on manually and avoid common errors that slow down the process.
Checking support for fast charging on Redmi 9
Before you try to enable accelerated charging, make sure your Redmi 9 does support it. Depending on the region and the firmware version (MIUI), some features may be limited.
- 🔍 Smartphone Model: Go to Settings → The phone. → Make sure you have a Redmi. 9 (The code name is Lancelot, not Redmi. 9A/9C — They don't have fast charging support.
- 📱 Version. MIUI: In the same section, check the firmware version. Quick Charge is recommended for full operation. MIUI 12.5 or newer.
- ⚡ Current Charging Mode: Connect your smartphone to charging and look at the lock screen. If it shows "Fast Charging" it's already active. If it's not, read on.
If you only see a standard charging icon on the lock screen without mentioning speed, it doesn't always mean that fast charging is off. It may be using an incompatible charger or cable. More on that in the next section.
What Chargers Are Good for Redmi 9
The Redmi 9 is compatible with Quick Charge 3.0, but it requires a charger that supports this standard to activate it, and it comes with a 5V/2A (10W) adapter that doesn't provide accelerated charging.
| Type of charger | Power | Compatible with Redmi 9 | Notes |
|---|---|---|---|
| Standard (from the set) | 5V/2A (10W) | ❌ No quick charging. | Charging in normal mode |
| Quick Charge 3.0 | 5V/3A, 9V/2A (18W) | ✅ Full support | The best option for Redmi 9 |
| Quick Charge 4.0/4.0+ | Up to 27W | ✅ Compatible (works as well as QC 3.0) | More expensive, but future-proof option |
| Power Delivery (PD) | Up to 30W | ⚠️ Partial compatibility | Can be slower than QC 3.0 |
In addition to the adapter, it is important to use a quality USB cable. Cheap cables with thin wires do not withstand high currents and automatically limit the charging speed, the best choice is the original cable from Xiaomi or a certified USB-C with 5A support.
⚠️ Note: If you connect Redmi 9 to a charge from another device (e.g., from a different device) POCO X3 Samsung, make sure that its power does not exceed 18W. Use of adapters on 30W+ It will not speed up charging, but it can cause the battery to overheat.
Step-by-step: how to turn on fast charging
If you already have a compatible charger, but the smartphone still charges slowly, it may be disabled in the settings.
- Connect your smartphone to a charger with Quick Charge 3.0 support.
- Unlock the screen and go to Settings → Battery and Performance.
- Click on Battery Settings → Charging Mode (in some versions of MIUI, the path may differ: Settings → Additional → Quick Charging).
- Activate the “Fast Charging” (or “Accelerated Charging”) switch.
- Reboot your smartphone if the changes don’t apply immediately.
When activated, the lock screen should show the words "Quick Charge" or "Quick Charge" if it is not, check:
Try another cable (original USB-C)
Connect another charger (18W+)
Update MIUI to the latest version
Reset the battery settings (Settings → Battery → Reset)
Check the temperature of the smartphone (when overheating, fast charging is turned off automatically)-->
If the fast charging failed after all the manipulations, the problem could be a firmware or hardware malfunction, in which case resetting to the factory settings or contacting a service center will help.
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Fast charging on Redmi 9 works only at a battery temperature of 10°C to 45°C. If the smartphone is overheated or too cold, the system automatically switches to standard mode.
Why fast charging might not work
Even if you did everything right, fast charging sometimes doesn't work, and here are the most common reasons and ways to fix them:
- 🔋 Battery wear: If the battery is worn out by more than 50%, the smartphone may limit current for safety. check battery condition in Settings → Battery → Battery status.
- 🌡️ Overheating: At temperatures above 45°C fast charging turns off. Let the phone cool down before connecting to the network.
- 📱 Background: If you run resource-intensive applications (games, video editing) during charging, the system can reduce the charging speed.
- 🔌 Failed port USB-C: Dust or moisture entering the connector may disrupt contact. Clean the port with compressed air or a soft brush.
Another possible reason is the firmware restriction: some regional versions of MIUI have software-enabled fast charging, in which case flashing to a global or European version of the software will help (but this voids the warranty!).
⚠️ Warning: If your smartphone starts to warm up or discharge quickly after activating fast charging, return to standard mode.
How to Optimize Charging to Extend Battery Life
Fast charging is convenient, but constant use can reduce battery life.To extend the life of the Redmi 9 battery, follow these tips:
- 🔄 Alternate modes: Use fast charging only when you need to urgently recharge (for example, before leaving.
- 🛑 Avoid 100%: Turn off charging when 80-90%.Constant charge to 100% accelerates degradation of lithium-ion batteries.
- 🌙 Charge at night in gentle mode: Turn on the function "Optimized Charging" in the battery settings. It will automatically limit the charge to 80% and wait for the morning hours to bring to 100%.
- 🔥 Control the temperature: Do not put your smartphone on charge in direct sunlight or near heat sources.
A critical nuance for Redmi 9 is that if you use a non-original charger above 18W, your smartphone can trick you into showing “Fast Charging” on your screen, but actually charging in standard mode. This is due to the limitations of the power controller. To check the real speed, use apps like AccuBattery or Ampere.
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If you often charge a smartphone from powerbank, choose models with Quick Charge 3.0 support (for example, Xiaomi Mi Power Bank 3 Pro).
Comparison of fast charging on Redmi 9 and other Xiaomi models
For clarity, compare the Redmi 9 with other popular Xiaomi smartphones in terms of charging speed:
| Model | Charging technology | Max. Power. | Charging time 0-100% | Notes |
|---|---|---|---|---|
| Redmi 9 | Quick Charge 3.0 | 18W | ~2 hours | The package includes 10W charging. |
| Redmi Note 9 Pro | Quick Charge 4.0 | 30W | ~1 hour | Charging complete |
| POCO X3 NFC | Quick Charge 3.0 | 33W | ~1 hour 10 minutes | Requires a proprietary adapter |
| Mi 11 | Quick Charge 5.0 | 55W | ~45 minutes. | Support for 50W wireless charging |
As you can see from the table, the Redmi 9 is significantly inferior to the flagship models in charging speed, but for the budget segment of 18W – a decent indicator. The main advantage is compatibility with a large number of chargers from other brands (for example, Samsung, OnePlus or Google).