Xiaomi Mi 9 is the flagship of 2019, which is still popular among users due to its powerful hardware and up-to-date firmware. But over the years, many owners have wondered: what kind of charging this smartphone supports, can you use modern adapters, and how to achieve maximum charging speed? In this article, we will examine all the nuances in detail, from official specifications to practical tips for choosing a charger.
Note right away: the Mi 9 supports fast charging, but not all adapters are equally efficient. Some users mistakenly believe that any high-power power supply is enough, but in practice, fast charging protocol, cable quality, and even the firmware version are important.
Official Charging Charging Characteristics Xiaomi Mi 9
According to the manufacturer’s documentation, the Xiaomi Mi 9 is equipped with support for the following charging standards:
- 🔌 Quick Charge 4+ (up to 27 W) – the main protocol used in the package.
- ⚡ USB Power Delivery (PD) — partial compatibility (up to 18 watts in most cases).
- 🔋 Standard charging. 5V/2A (10 WW – works with any adapter, but slowly.
The Mi 9 included an MDY-11-ED (27W Quick Charge 4+) adapter that provides 0 to 100% charging in about 1 hour 10 minutes (under ideal conditions), but many users lose their native power supply or want to use universal solutions such as charging from other Xiaomi devices or third-party brands.
It is important to understand that the maximum power of 27 watts is achieved only if three conditions are met:
- Use of an original or certified USB Type-C cable.
- Quick Charge 4+ or USB PD (but not all versions!)
- The battery temperature is in the range of 15-35 ° C (when overheating, the speed automatically decreases).
Compatible with different fast charging standards
One of the key features of the Mi 9 is that it supports multiple fast-charging protocols, but not all of them work equally well.
| Charging standard | Max. Power to Mi 9. | Required adapter | Notes |
|---|---|---|---|
| Quick Charge 4+ | 27 Watts | MDY-11-ED (from the kit), adapters with QC 4+ | The best option for maximum speed. |
| USB Power Delivery (PD) | 18 W. | Anybody. PD-Adapter (MacBook, Google Pixel, etc.) | It works, but slower than QC 4+. PD-enabled cable is required. |
| Quick Charge 3.0 | 18 W. | Adapters with QC 3.0 (e.g. from Xiaomi Mi 8) | Compatible, but not fully exploiting the potential of the smartphone. |
| Standard charging (5V/2A) | 10 Watts. | Any adapter. | Slowly, charging to 100% will take ~2.5 hours. |
Fun fact: The Mi 9 can be negotiated with USB PD adapters up to 18 watts, but only if the cable supports USB-C 2.0 or higher. Cheap cables often limit power to 10-15 watts, even if the adapter is capable of more.
⚠️ Note: Some adapters with USB PD 3.0 (for example, from MacBook Pro 2020)+) Mi 9s can be misidentified, causing charging to go at reduced power, in which case it will help to reboot the smartphone or use another cable.
Can I use charging from other Xiaomi devices?
Many users want to save money and use chargers from other Xiaomi gadgets, so let’s figure out which adapters will work and which won’t.
- ✅ Xiaomi Mi 10/11/12 (33–67 Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-Wh-W 27 W (limitation of the Mi itself) 9).
- ✅ Xiaomi Redmi Note 10 Pro (33W) – compatible, speed ~25 W.
- ❌ Xiaomi Mi 8/8 Pro (Quick Charge 3.0) — charging 18 Watt, slower than the native adapter.
- ⚠️ Xiaomi Pocophone F1 (Quick Charge 3.0 – works, but warms up more because of the outdated protocol.
The best option among the “non-fast” charges Xiaomi — adapters from Mi 10 or Mi 11 with support for Quick Charge 4+. They will provide the same speed as the original unit, but with the ability to use for other devices.
💡
If you travel frequently, bring a compact adapter Xiaomi 33W GaN (MDY-12-EG). It is lighter than the original, supports QC 4+ and PD, and is suitable for Mi 9, laptop or headphones.
But the charges from Redmi or POCO with power 18-22.5 watts will run slower. For example, the adapter from Redmi Note 9 Pro (33 watts) will give the Mi 9 only ~18 watts due to the difference in protocols.
How to check the actual charging speed?
To find out how much power your Xiaomi Mi 9 is charging, you can use several methods:
- AccuBattery (Android): Install from Google Play. Connect charging and open the Charging tab. The app will show the current power in mW.
Hidden Engineering Menu
##4636##Go to the Battery Information, and you'll see the charging current (AC or USB) and multiply the volts by amps to get the power.
USB-tester
Connect between the adapter and the cable, and it'll show you the exact voltage and current.
When testing, pay attention to:
- 📉 In the first 10-15 minutes, charging is at maximum power, then the speed drops (especially after 80%).
- 🔥 If the smartphone is heated above 40°C. The system forcibly reduces power.
- 🔌 The quality of the socket and the extension also affects speed! old wires can "cut" power.
Why is the Mi 9 slowly charging from Power Bank?
Which cables are suitable for fast charging?
Even the most powerful adapter is useless without the right cable. For the Xiaomi Mi 9, it is critical to use a cable that supports Quick Charge 4+ or USB Power Delivery.
- ✅ Original cable from the kit - the best option (marking) USB-C to USB-A or USB-C to USB-C).
- ✅ Certified cables USB-IF (For example, Anker PowerLine, UGREEN).
- ❌ Cheap no-name cables – often limit current, which is why charging goes for 10-15 watts.
- ⚠️ Cables from older smartphones (until 2018) – may not support high currents.
Pay special attention to the length of the cable:
- 📏 0.5-1 m - minimum power loss.
- 📏 1.5-2 m - possible losses of up to 2-3 W.
- 📏 3 m or more – charging speed can drop by 20-30%.
If you use USB-C to USB-C cable, make sure it supports 5A (This is usually indicated on the package or cable itself. USB-A to USB-C Quick Charge Support 3.0/4+.
Has USB-IF or MFi | Certified Supports a current of at least 3A (for QC 4+)| Length not exceeding 1.5 m for minimum losses | Resistance not higher than 0.5 ohms (indicated in specifications) | Complies with USB 2.0 or higher-->
Frequent problems and their solutions
Xiaomi Mi 9 users sometimes experience charging problems, and here are the most common cases and ways to fix them:
| Problem. | Possible cause | Decision |
|---|---|---|
| Charging is very slow (5-10 W). | Use an uncertified cable or adapter | Replace the cable/adapter with an original or certified cable |
| The smartphone does not determine charging | Contaminated USB-C port or damaged cable | Clean the port with a wooden toothpick, check the cable on another device |
| Charging is interrupted or "jumps" | Unstable voltage in the network or damaged adapter | Connect to another socket, try another adapter |
| The smartphone is very warm when charging | A powerful adapter is used without QC 4+ support. | Switch to original charging or reduce the load (close applications) |
If the Mi 9 has stopped charging, check:
- Integrity of the cable (especially at the base of the connectors).
- USB-C port cleanliness (dust and debris can block contacts)
- The adapter is capable (try charging another device).
- Battery status (see Battery Health parameter in AccuBattery).
⚠️ Warning: If you connect a charger to a smartphone and it says, "This charger is not supported," but it's still charging, it's not a mistake! So Mi 9 warns you're using a suboptimal adapter, and the charging speed may be lower than normal.
Recommendations for the choice of a charger in 2026
If you lost your original charger or want to buy a spare adapter, here are the current guidelines for 2026:
- 🥇 Best pick: Xiaomi 33W GaN Charger (MDY-12-EG) — compact, supportive QC 4+ and PD, It is suitable for Mi 9 and other devices.
- 💰 Budget option: Baseus 30W GaN – inexpensive but reliable adapter with support for fast charging.
- 🔌 The Anker 735 (GaNPrime) 65W) — It will charge both the Mi 9 at full speed and the laptop.
- 🚗 For cars: Xiaomi Car Charger QC 3.0 will give ~18 watts, which is faster than standard car charging.
When buying, pay attention to:
- Certification (the package must be QC 4+, USB-IF or PD signs).
- Maximum current (for Mi 9, 3A is enough, but 5A is better for the reserve).
- Reviews – check if there are any complaints of overheating or slow charging.
Avoid unlabeled adapters or those with suspiciously low prices – they can damage your battery or smartphone.
💡
For maximum charging speed Xiaomi Mi 9 need an adapter with Quick Charge 4+ (27 watts) and a quality USB-C cable. USB PD works, but slower (18 watts).