Owners of Xiaomi, Redmi and POCO smartphones often notice unusual behavior of indicators on the lock screen while connecting to the power source. Instead of the usual one zipper or battery icon, two lightning bolts appear, which puzzles inexperienced users. This visual signal is not a system error or a sign of failure, but serves as an informative indicator of the state of the charger.
The dual lightning symbol is directly related to the fast charging technology embedded in the MIUI and HyperOS shell. The system automatically recognizes the power of the connected adapter and tells the user that the device has switched to accelerated power recovery mode. Understanding this mechanism allows you to control the charging process and avoid the use of poor-quality accessories that can damage the lithium polymer battery.
In some cases, a double lightning may indicate an unstable contact or software failure if the fast charging mode is not activated and the indicator flashes. Next, we will discuss in detail what this signal means in different scenarios, how to distinguish normal operation from malfunction and what steps to take if the charging speed does not match the manufacturer's stated.
The main value of the indicator of double lightning
The main reason Xiaomi's two lightning bolts are on the screen is to activate its fast charging mode. The company has developed its own technology that allows you to transfer increased current and voltage to the battery without the risk of overheating. When you see this icon, it means that the smartphone has "agreed" with the charger to increase power.
Depending on your gadget’s model, two lightning bolts can mean support for Quick Charge or the proprietary HyperCharge protocol. On the Redmi Note’s budget models, for example, this can mean a standard 18W, while on Xiaomi’s 13 or 14 flagships, the same symbol signals power of 67W, 90W, or even 120W.
⚠️ Warning: If two lightning bolts are on fire but the phone is charging slowly, it is possible that the cable is damaged inside and unable to pass the required current despite protocol recognition.
It's important to understand that this indicator only lights up when you connect the cable to the connector or when you turn on the screen while charging. If you unlock the device and see an icon in the notification curtain, it will also display the status of "Fast Charging" or "Fast Charging" to help the user make sure that they are using an original or certified power supply.
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Two lightning is a standard indicator of the fast charging technology, confirming that the phone gets the maximum power from the adapter.
Differences of regimes: one lightning versus two
Users are often confused about the indication, especially after updating the firmware or changing the phone's model.Single lightning usually means standard charging mode. 5V/2And (10 W), which is considered basic for most USB-In this mode, the heating of the device is minimal, but the time for full recovery of the capacity is much higher.
Two lightning strikes when the voltage rises to 9B, 12B or higher, depending on the protocol supported. The power controller's safety system constantly monitors the battery temperature. If the sensors detect overheating, the number of lightning can decrease to one, and the charging speed will artificially decrease to preserve the battery cell's life.
- ⚡ One Lightning: Standard charging (usually 10W), safe for night use, minimal battery wear.
- ⚡⚡ Two Lightnings: Fast charging (18W – 33W), optimal for daytime use, requires temperature control.
- 🌩️ Lightning with numbers/degrees: Superfast charging (67W and above), available only on flagship models with appropriate support.
Interestingly, some global firmware versions may have different displays than their Chinese counterparts. In China, it often uses a high-charge animation with a large lightning icon, while the global version of MIUI emphasizes conciseness. If you refashion the device, the character set may change, but the logic of the power controller will remain the same.
Technical reasons for the appearance of the symbol
The software shell is responsible for displaying graphic elements on the screen, but the decision to go into fast charging mode is made by the hardware. The key element here is the power controller, which reads the resistance on the Data contacts.+ data- USB-And that's the parameter that makes the smartphone know which adapter is connected to it.
If the resistance meets the QC 3.0 or PD specification, the system commands to increase the voltage. Two lightning bolts light up as confirmation of a successful handshake between devices. If cheap Chinese cables are used without shielding, the resistance can be unstable, leading to constant switching between one and two lightning bolts.
It is also worth considering the state of the USB-Over time, dust and pile accumulate in a Type-C or Micro-USB port, which worsens contact. Bad contact can be perceived by the controller as a signal to reduce power, and the second lightning will go out. Regularly cleaning the port helps to avoid false positives.
adb shell dumpsys batteryFor advanced users, it is possible to check the charging status through the ADB debugging menu. The command above will display detailed information about the current battery status, including charge level, connection status and charging technology. This helps diagnose problems when the display on the screen does not match the real values.
Problems and malfunctions of the indicator
Although two lightning bolts are a good sign, sometimes their behavior can indicate problems: If the symbol flashes, fades and lights up again without the cable being turned off, it is a sign of unstable voltage, and such jumps are harmful to the power controller and can cause it to prematurely fail.
A common problem is when two lightning bolts are on, but the phone is not charging or the charge is extremely slow, this can be caused by a software failure in the MIUI drivers, in which case it helps to restart the device or reset the settings to factory, if the problem is systemic.
⚠️ Warning: Using damaged cables with visible insulation fractures can short circuits even if the indicator shows two lightning bolts.
Another possible reason is the wear and tear of the battery itself: if the battery is several years old, its internal resistance increases. A smartphone may try to start a fast charge (two lightning bolts), but physically cannot take high current, dropping power, in which case the system may mistakenly display the fast charge indicator, although in fact it is normal current.
Why does the phone warm up with two lightning bolts?
How to check the real charging speed
To make sure that two lightning bolts are not just a picture, but a real fast charge, you can use third-party utilities. Apps like Ampere or Cpu-Z allow you to see the current in real time. Standard charging is usually 1000-1500 mA, whereas fast charging can reach 3000 mA and higher.
Also worth paying attention to the time it takes to charge from 0 to 100%. For modern Xiaomi models with a capacity of 5000 mAh and support for 33 W, the normal time is about 60-70 minutes. If the process takes 2-3 hours, despite the burning of two lightning, then the fast charging mode is not working correctly.
| Adapter power | Charging time (5,000 mAh) | Indication | Technology |
|---|---|---|---|
| 10 W (5V/2A) | ~2 hours 30 minutes | 1 lightning | Standard |
| 18 W (9B/2A) | ~1 hour 40 minutes | 2 lightning | Quick Charge 3.0 |
| 33 Watts | ~1 hour 10 minutes | 2 lightning | MI Turbo Charge |
| 67 W and higher | ~40-50 min | Lightning + numbers | HyperCharge |
Remember, the charging speed is nonlinear. The maximum power is only supplied in the range from 0 to 60-70%. The current is then reduced to prevent overcharging and swelling of the battery. So the last 20% can be charged as slowly as using a conventional charge.
Recommendations for extending battery life
Constant use of fast charging mode, which is indicated by two lightning, accelerates the chemical wear of the battery.If you do not need to leave the house urgently, it is better to use a less powerful power supply or wireless charging, if it is supported by your Xiaomi model.
Try not to drain your phone to 0% and keep it on charge at 100% all the time. The optimal range for lithium batteries is 20% to 80%. MIUI settings often have an Optimized Charging feature that learns your habits and pauses charging at 80%, completing the process just before you wake up.
- 🌡️ Temperature: Do not charge your phone in direct sunlight or on soft surfaces that block ventilation.
- 🔌 Accessory quality: Use original cables or certified analogues (MFi, QC certified).
- 🔋 Cyclicality: Avoid deep discharge, try to put the phone on charge when charging 15-20%.
☑️ Checking the state of charge
If you notice that the phone is rapidly discharged, warms up with a simple lightning or two lightning appear chaotic, it may be time to replace the battery. In authorized service centers Xiaomi can conduct a diagnostic of the state of the battery (SOH) and give accurate recommendations.
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For night charging, it is better to use the old power supply on 5V/2A (one lightning) - this will significantly reduce heating and prolong the battery life.