How to enable reverse charging on Xiaomi Redmi 9T: a complete guide with nuances

What is Reverse Charging and Why You Need It in the Redmi 9T

Xiaomi’s reversible charge feature allows the device to be used as a portable power bank, which means recharging other gadgets from its battery. In Redmi 9T, this option is implemented at the hardware level, but by default it is disabled. Many users do not even know it exists, although it can help in situations where there is no outlet or external power bank at hand.

The main advantage of reverse charging is its versatility, and it can charge:

• 📱 Other smartphone (including iPhone, Samsung, Huawei models)
• 🎧 Wireless headphones (AirPods, Xiaomi AirDots, Sony) WH-1000XM4)
• ⌚ Smart watches (Mi Band, Apple Watch, Galaxy Watch)
• 💡 Compact gadgets (fitness trackers, electronic cigarettes, portable speakers)

However, there are limitations. Redmi 9T supports reverse charging only on a wired connection (via USB-C) - wireless power transfer (like the flagship Xiaomi 13 Ultra) is not provided here. In addition, power is limited to 5W, which is noticeably slower than standard charging from the outlet. But in emergency cases, even this is enough to "resuscitate" the sat down gadget.

Conditions for reversible charging on Redmi 9T

Before you try to activate the feature, make sure your device meets the key requirements:

Critical: Reverse charging only works when connected via USB-OTG, which means your Redmi 9T must recognize external devices as a host. If you haven't used an OTG before (for example, to connect a flash drive), the function can be disabled at the system level, in which case it will have to be activated manually, which we will discuss in the next section.

⚠️ Note: If the battery level of Redmi 9T below 20 percent, the system will block reverse charging to avoid a full discharge, which is protection against a sudden shutdown of the phone during the power transfer process.

Step-by-step: how to turn on reverse charging

Activation of the function takes less than a minute, but requires precise steps. Here is the universal algorithm for Redmi 9T on any version of MIUI (12 to 14):

1. Connect the OTG cable to the USB-C port of your Redmi 9T. Connect the other end of the cable to the charging device.
2. Unlock the smartphone screen – the function does not work in a locked state.
3. Swipe down the notification bar and find the Reverse Charging icon (the zipper and back arrow icon).
4. Stick to the icon to activate the mode, and the screen will show a notification of the beginning of the power transfer.

If the icon is not in the notification bar, it means the function is hidden.

1. Go to Settings → Connected devices → Reverse charging.
2. Activate the Show switch in the notification panel.

Check the Redmi 9T charge level (minimum 20%)

Use the original USB-C cable

Unlock the phone screen

Connect the charging device before activating the function

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Important: Some MIUI 13+ firmware may not have a reverse charging icon even after the display is turned on, in which case activation occurs automatically when a compatible device is connected - just wait for the notification to start charging.

Why Reverse Charging May Not Work: Common Problems

Even when connected correctly, the function sometimes fails, and here are the typical reasons and ways to fix them:

• 🔋 Low battery charge (<20%) → Get Redmi on board. 9T chargeable 10–15 minute.
• 🔌 Faulty cable → Try another one. USB-C cable (preferably original).
• 📱 Incompatible device → Make sure that the charging gadget supports charging on USB (For example, the iPhone requires a certified Lightning cable.→USB-C).
• 🔄 System failure → Reboot Redmi. 9T and try again.
• 🛠️ Unplugged. OTG → Include it in Settings → Additionally. → Regime. OTG.

If the problem persists, check the developer's settings:

1. Activate Developer Mode (7 times tap the MIUI version in About Phone).
2. Go to Settings → For developers and find the Debugging by USB.
3. Enable the default USB configuration option and select Charge.

⚠️ Note: Some custom firmware (such as LineageOS or Pixel Experience) may have reverse charging disabled at the kernel level, requiring manual editing of the build.prop file or installing the Magisk module.

Charging speed and process optimization

As mentioned, the Redmi 9T transmits power up to 5W, enough to recharge smartphones or gadgets with small batteries slowly.

• 📱 iPhone 13 (battery 3095 mAh) – charging from 0% to 10% ~30 minutes.
• ⌚ Mi Band 7 (Battery 180 mAh) – full charge for the first time ~1 hour.
• 🎧 AirPods Pro (Battery 519 mAh) – charging from 0% to 50% ~40 minutes.

To speed up the process:

• 🔌 Use a short cable (up to 50 cm) to reduce energy loss.
• 📴 Turn it off on Redmi. 9T background applications and Wi-Fi/4G, to reduce battery load.
• 🔋 Get Redmi on your own. 9T charging (e.g. power bank) – this will allow both devices to be charged at the same time (although the power transfer rate will remain at the same level). 5W).

It's worth noting that when you reverse charge, the Redmi 9T discharges at about 1% per minute (when you transfer 5W), so in 30 minutes you'll give up about 30% of your battery.

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If you need to charge a device with a Lightning connector (such as an iPhone), use a certified USB-C→Lightning cable. Cheap uncertified cables can block power transmission due to the lack of an authentication chip.

Security: Myths and Real Risks

There's a lot of rumors going around reverse charging, from "this is ruining the battery" to "you can burn the phone."

Myth 1: “Reverse charging kills the battery quickly”

Reality: Today's lithium-ion batteries at Xiaomi are designed to last hundreds of charge/discharge cycles. A single reversible charge reduces battery life by no more than a normal discharge by 20 to 30 percent. 9T in the process (below 5%).

Myth 2: You can burn a USB-C port.

Reality: Redmi 9T offers protection against overheating and short circuiting, and the risk of port damage is minimal if you use certified cables and don't connect devices with damaged connectors.

Real risk: overheating

If the Redmi 9T is heated above 40°C (for example, it is in direct sunlight), the system will automatically turn off reverse charging.

• 🌡️ Do not use the function at ambient temperatures above 30°C.
• 📵 Remove the phone case for better cooling.
• ⚡ Do not charge two devices at the same time (for example, via a hub).

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Reverse charging is safe for the Redmi 9T, as long as you follow three rules: avoid overheating, use original cables, and do not discharge the phone below 5%.

Alternatives to reverse charging: when it doesn't fit

If you need to charge other devices from your smartphone regularly, reverse charging can be uncomfortable due to low speed and limitations.

For most users, the best solution is a compact power bank at 10,000 mAh (for example, Xiaomi Mi Power Bank 3), which charges from the Redmi 9T in 3-4 hours and can then give power to several devices with power up to 18W.

If you need reverse charging "here and now", and at hand only Redmi 9T, use our instructions - it will help in an emergency.

FAQ: Answers to Frequent Questions