How to share charging from phone to phone without a Xiaomi wire

The situation when a smartphone discharges at the most inopportune moment is familiar to every owner of a gadget. Especially offensive if there is no power bank at hand, and there is a device with a full battery nearby. Fortunately, modern flagship smartphones Xiaomi and Redmi are equipped with a reversible wireless charging function. This technology allows you to use the phone as an external battery to power other gadgets that support the Qi standard.

Unlike wired connectivity, which requires special OTG cables and related software, the wireless method works through the back of the device. The power transfer is through electromagnetic induction. However, not all models of the brand support this option, and the activation process has its nuances in the shell of MIUI and HyperOS. In this guide, we will discuss all the finer points of setting, compatible devices and ways to optimize the process.

Before you start charging, it's important to understand the physical limitations of the method. The power transfer rate here is much lower than with a wired connection, and averages 10 to 20 watts depending on the donor model. The efficiency of wireless power transmission is about 60-70%, so some of the charge is always lost as heat. This means that a fully discharged phone you will charge slowly, but urgently raise the battery level by 10-15% for an important call is quite real.

Principle of operation and compatible devices

Reverse charging technology is based on the Qi standard (pronounced "Qi"). Inside the smartphone case, a special coil module is built that, when applied to voltage, generates an electromagnetic field. When another device is placed on the back, a current is generated in its coil that charges the battery. To work properly, both devices must support this standard.

Not all of the Chinese giant’s smartphones are capable of powering out, mostly reserved for Mi flagship lines and the top-end Redmi Note models with the Pro or Ultra prefix. Budget devices tend to lack a second coil or the necessary power controller to avoid overheating and battery life decline.

  • 📱 Xiaomi Mi 9, Mi 10, Mi 11, Mi 12, Mi 13, Mi 14 and Pro/Ultra version
  • 📱 Xiaomi MIX 2S, MIX 3, MIX 4
  • 📱 Redmi Note 10 Pro, Note 11 Pro, Note 12 Pro, Note 13 Pro
  • 📱 Black Shark 2 Pro, 3, 4, 5 (Gaming Smartphones)

It is worth noting that having wireless charging on reception does not guarantee the possibility of working on recoil. For example, some older models were able to receive current through the air, but did not have the software or hardware to reverse, so before trying to charge a friend, you should check the specifications of your device in the Settings → About the phone or on the official website.

📊 Does your Xiaomi have a reverse charger?
Yes, flagship.
Yeah, middle class.
No, I don't know.
Planning to buy

Activation of the function in the MIUI and HyperOS settings

Turning on the external battery mode in the shells from Xiaomi is implemented as simple as possible, but users often can not find the right switch in the depth of the menu. The system groups the power consumption parameters in a separate unit. You do not need superuser rights or third-party applications to start working.

The algorithm is the same for most current firmware versions, so you first unlock the screen and open the main menu, then follow the Settings → Battery path, and in the window that opens, you'll see a power graph and some icons at the top of the screen, and that's where the switch is.

☑️ Incorporation algorithm

Done: 0 / 4

If you're using a new HyperOS shell, the layout of the elements may have changed slightly, but the logic has remained the same. Sometimes the switch is put into the notification curtain for quick access. To add it to it, open the control center, click on the edit pencil and find "Reverse Charging" or "Wireless Reverse Charging".

⚠️ Note: The function will automatically shut down after a certain time (usually) 2-3 minutes), if the phone is not connected to the charger, this is done to prevent the user from wasting energy.

Safe use rules

Using a smartphone as a power bank puts additional strain on the battery and processor. During operation, the inductor is heated, which, combined with the heating from the chemical reaction in the battery, can lead to overheating of the case. Manufacturers implement protective mechanisms, but the user should also be careful.

It is strongly recommended not to cover devices with a blanket, pillow or dense fabric during the process. A heat sink violation can cause an emergency shutdown or, in rare cases, battery bloating, and avoid direct sunlight falling on the back panel of smartphones.

  • 🌡️ Watch the temperature: If the phone gets hot, stop the process
  • 📵 Remove thick covers from both devices for better contact
  • 🔋 Do not use the function if the donor charge is lower 20-30%
  • 🚫 Do not put metal objects (keys, coins) between phones)
Why is the phone warming up?
Reversible charging doubles the energy conversion: chemical to electrical, then electromagnetic, and again electrical and chemical in the receiving device, and at each stage, some of the energy that is released as heat is lost. It's a normal physical process, but it requires control. Performance comparison: wire versus air Many users mistakenly assume that air charging speed is comparable to cable charging. In practice, the difference is huge. USB Type-C can be issued 30, 60 even 120 The wireless reverse is limited by physical safety standards and usually does not exceed 10-15 Watt, and often works even slower. For clarity, compare the parameters of the two methods of power transmission in the context of Xiaomi devices. The wired method is ideal for quick "swinging" of the battery, whereas the wireless method is a solution for emergency situations "to catch (OTG) Wireless (Reverse) Maximum power up to 18-27 W (depending on port) Do 10-15 Waht (realistically) 5-8 W) Transmission efficiency Near 90-95% Around 60-70% Heating devices Moderate High Usability Requires cable Put and forget As you can see from the table, the wireless method is a significant loss. You can spend 20% Your phone is only to add to another phone. 10-12%. So it's not a good way to rely on this as the primary way to charge when traveling, and it's not a good way to solve problems and errors, even on compatible devices, it might not start the first time. MIUI has strict protection algorithms that block current transmission when potential risks are detected. Often users are faced with a situation where the charging indicator on the receiving device does not light up. One of the common reasons is the mismatch of the centers of the coils. The induction module in Xiaomi smartphones is usually located at the top of the case, closer to the center. If you put your phone flat, the centers may not match, try to move the top device a little higher or lower until you have vibration or start charging sound, and check your energy saving settings. In some scenarios, the Superpower Saving mode may block background processes and external connections to save each percent. ⚠️ Warning: If the donor’s phone is depleted to a critical level (usually less than 10%), the system will force reverse charging to keep emergency calls possible. Smartphone protective gear is an important factor in induction efficiency. Thick silicone, leather or shock-proof cases create additional distance between the coils. According to the laws of physics, the strength of the electromagnetic field drops dramatically with increasing distance. Especially critical are cases with metal elements, magnetic latches or built-in holders for cars. Metal shields the field and can cause the case to heat up, which is dangerous for both devices. 🛑 Remove the covers with metal inserts 🛑 Remove your bank cards from your bookcase (can get hot) ✅ Thin plastic and silicone cases usually do not interfere ✅ MagSafe rings (on iPhone) may interfere with contact 💡The ideal charging environment is two devices without cases, lying flat on top of each other in the center of the coils, in a cool room. Can you charge an iPhone from Xiaomi? Yes, you can. iPhones support the Qi standard. However, the speed will be limited by the iPhone's capabilities (usually 7.5 watts for wireless charging), even if Xiaomi is able to give more.The process will take longer than charging an Android smartphone. It's probably a foreign object protection system, so check if there's something metal between the phones. Also make sure that the receiving device is wirelessly charged and the screen is not on all the time. Does this damage my Xiaomi battery? Frequent use of reverse charging leads to additional heating and discharge cycles, which theoretically accelerates the degradation of the lithium polymer battery. In case of emergency, this is safe, but it is not necessary to do this daily habit. What is the minimum charge required for start? It is recommended that the donor charge is at least 30%. At lower values, the system can issue a warning or not turn on the energy efficiency mode, prioritizing the device's own needs.