Xiaomi Mi 8: Charging power, compatible adapters and how to speed up the process

The Xiaomi Mi 8, launched in 2018, has become one of the brand’s flagship devices with top-end hardware and fast charging support. However, users are still confused about its charging power: which adapters are suitable, whether more powerful power supplies can be used and how to achieve maximum speed. In this article, we will analyze all the nuances of charging the Mi 8, including official data, real-world user tests and tips for optimizing the process.

Many people mistakenly believe that the smartphone supports Quick Charge 4+ just because it comes with an 18W adapter. In fact, the situation is more complicated: it plays a role and firmware, cable, and even battery temperature. We analyzed the technical documentation, feedback from owners and independent tests to give a clear answer: how many watts does the charging Xiaomi Mi 8 and how to check it yourself.

If you're looking for a specific answer, you can go straight to the adapter power table or the FAQ. For those who want to get a little deeper, we've prepared an expanded guide that explains all the technical points.

Official Charging Charging Characteristics Xiaomi Mi 8

According to the manufacturer, the Xiaomi Mi 8 supports Quick Charge 4+ (QC 4+) technology, but with an important caveat: maximum charging power is limited to 18W. This means that even if you plug in a 27W or 33W adapter (such as from the Mi 9 or Mi 10), the smartphone will not consume more power than its power controller allows.

The Mi 8 comes with an MDY-08-EM adapter with the following characteristics:

• 🔌 Input: 100–240 B, 50/60 Hz, 0.5 A
• ⚡ Exit: 5V/3A, 9V/2A, 12V/1.5A (max. 18W)
• 🔗 Cable: USB Type-C → USB Type-A (length 1 m, supports QC 4+)

It is important to understand that the actual charging power depends not only on the adapter, but also on:

• 📱 Firmware versions (old builds MIUI may have limitations)
• 🌡️ Battery temperature (power automatically decreases when overheated)
• 🔋 Charge level (at the last 20%, the speed drops to protect the battery)

Real tests: how many watts does the Mi 8 give out in practice

Independent tests (e.g. from TechTablets or GSMArena) show that the Xiaomi Mi 8, ideally, consumes up to 17–18 watts using the original adapter.

When you connect adapters with Quick Charge 3.0/4+ support (e.g., Mi 9 or Poco F1), the power stays at 18 W — the smartphone cannot exceed this threshold due to hardware limitations. But with adapters without QC (e.g., standard 5B/2A), the charging speed drops to 10 W.

Critical: If you use a non-original cable without QC 4+ support, power can drop to 5-7 watts even with a proprietary adapter, which is because the fast charging protocol requires a special firmware in the cable to transmit data about the supported voltages.

⚠️ Warning: If your Mi 8 charges slower than the table indicates, check the cable for damage. Often the problem lies in the cliff wires inside the insulation, which leads to a power drop of up to 5 watts.

How to check the real charging power

To find out how many watts your Xiaomi Mi 8 is currently consuming, use one of the following methods:

Appendix AccuBattery (Android):

• 📊 Shows the current charging power in real time.
• 📉 Builds charge/discharge velocity graphs.
• ⚠️ Requires calibration (first 2-3 charge cycles).

Engineering menu (hidden mode):

1. Enter the code: ##4636###.

3 USB-tester (hardware method):

Devices like USB Power Meter (~500 RUB) show the exact voltage and current. Connect the tester between the adapter and the cable, then start charging. For example, at readings 9V × 2A = 18 W everything works correctly.

Check the adapter for compatibility with QC 4+|

Use the original USB Type-C| cable

Update your firmware to the latest version of MIUI|

Clear the charging port from dust and debris |

Reboot your smartphone (sometimes helps reset the power controller)-->

How to speed up charging Xiaomi Mi 8: 5 working ways

Even with a limit of 18 watts, you can optimize the process.

1. Energize Aircraft Mode:

Shutting down the network (Wi-Fi, LTE, Bluetooth) reduces the load on the processor, which allows you to direct more power to charge, according to tests, this speeds up the process by 10-15%.

2. Use an adapter with a QC 4+:

Although the Mi 8 will not exceed 18 watts, Quick Charge 4+ adapters (e.g., 27W MDY-10-EC) provide more stable voltage than cheaper ones.

Charge at a temperature of 20-25°C:

When heated above 30°C, the power controller automatically reduces power. Avoid charging in the sun or near heat sources.

4. Turn off background processes:

Close resource-intensive applications (games, navigators) and turn off sync.

1. Go to Settings. → Battery.
2. Choose Battery Optimization.
3. Turn off auto-run of unnecessary applications.

Calibrate the battery every 3 months:

This helps to reset the power controller errors.

• 🔋 Discharge your smartphone to 0% (until it shuts down).
• ⚡ Charge to 100% without interruption.
• 🔄 Repeat the cycle 2-3 times.

💡

If you frequently charge your smartphone from a laptop or powerbank, use a USB-PD cable (like a MacBook) that will provide stable 15-18 watts even from weak sources.

Wireless charging: myths and reality for the Mi 8

Xiaomi Mi 8 supports the Qi standard, but with serious limitations:

• ⚡ Maximum power: 5-7 W (instead of the claimed 10 W).
• ⏱️ Full charge time: 3.5-4 hours (vs. 1.5 hours with wired adapter).
• 🔥 Heating: Wireless charging heats smartphone more, which shortens battery life.

If you want to use wireless charging, choose a Qi 1.2.4-enabled station (such as the Xiaomi Wireless Charging Pad or Belkin Boost Up). Avoid cheap Chinese devices, which often fall short of standards and can damage the battery.

⚠️ Warning: When using wireless charging, the Mi 8 can overheat and automatically turn off power. If this happens, remove the case and place the smartphone on a flat surface for better cooling.

Typical Mi 8 charging problems and their solutions

1.The smartphone does not charge at all:

• 🔌 Check the socket and cable (try another adapter).
• 🧹 Clean the port USB-C of dust with a toothpick (carefully!).
• 🔄 Reboot the device (sometimes helps when the controller fails).

2. Charging is jerky (it turns on, then turns off):

It's a sign of bad contact.

• 🔌 Cable damaged (broken at base)
• 📱 Contacts at port USB-C have been oxidized.
• 🔋 Battery malfunction (blown or worn out).

Slow charging (less than 10 W):

It's probably a cable or an adapter problem.

• ⚡ Use the original adapter MDY-08-EM.
• 🔗 Replace the cable with a certified cable (with QC 4+ support).
• 📱 Update the firmware (older versions MIUI had power-limited bugs).

4.The smartphone warms up and turns off charging:

It's a heat protection, so you don't have to have a problem.

• 🌡️ Charge at temperatures below 25°C.
• 📵 Turn off background processes (games, navigation).
• 🔋 Remove the case (especially silicone).

💡

If the Mi 8 stopped charging quickly after the firmware update, try rolling back to the previous MIUI or resetting. Some builds (e.g. MIUI 12.5) had power-limiting bugs.

FAQ: Frequent questions about charging Xiaomi Mi 8