Why Does Charging Speed Drop When Plugging in Two Devices?

In today’s digital – product filled world, fast – charging tech is key for efficient living. But many users find that when using a multi – port fast charger, charging speed drops if two devices are plugged in at the same time. What’s behind this? Let’s explore the secrets of multi – port fast – charging dynamic power allocation.

I. Smart Power Allocation Protocol: Priority Logic Determines Charging Order

• PowerIQ 4.0 Protocol’s Priority Rules: Multi – port fast chargers often use the PowerIQ 4.0 protocol, which allocates power based on factors like device power demand, battery status, and connection order. For example, if a notebook (around 80W demand) and a smartphone (15W demand) are connected at the same time, the protocol prioritizes the notebook’s higher – power needs, charging it quickly first. Once the notebook’s battery level rises and its power demand decreases, the remaining power is allocated to the smartphone.
• Advantages Over Traditional Fixed – Power Allocation: Traditional fixed – power allocation chargers have fixed power output per port. Take a dual – port charger with each port fixed at 30W output as an example. When connecting a notebook and a smartphone, the notebook charges slowly due to insufficient power, while the smartphone may face over – charging risks. In contrast, the dynamic allocation of PowerIQ 4.0 can flexibly adapt to various devices, avoiding power waste and enhancing safety.

II. Real – World Testing Data: Actual Power Curves When Charging a Notebook and Smartphone Together

• Real – World Testing Scenario and Devices: A multi – port fast charger supporting the PowerIQ 4.0 protocol was selected and connected to a notebook (around 80W demand) and a smartphone (15W demand). Professional equipment monitored the power allocation during charging.
• Power Variation Curves and Analysis: Test results showed that in the initial charging stage, the charger allocated almost all power to the notebook, which charged at nearly 80W, while the smartphone received only 5W trickle charging. As the notebook’s battery level increased from 20% to 60% (in about 30 minutes), its power demand decreased. The charger gradually allocated the excess power to the smartphone, increasing its charging power to around 10W, with the notebook stabilizing at 50 – 60W. When the notebook’s battery approached 90%, the charger further adjusted, reducing the notebook’s power to 30 – 40W and stabilizing the smartphone’s power at 12 – 13W until fully charged. This highlights the PowerIQ 4.0 protocol’s on – demand power allocation, ensuring high – power devices charge quickly first while also catering to low – power devices.

III. Deceptive Solutions: The Risks of Using Triggers to Force Single – Port Full – Power Output

• How Triggers Work: “Triggers” on the market simulate device electronic characteristics, sending false signals to the charger to make it think only a high – power – demand device is connected, thus locking the single – port to full – power output. For instance, a trigger can mimic a notebook’s high – power – demand features, causing the charger to focus all its power output on one port.
• Safety Risks and Hazards: Triggers disrupt the charger’s power – allocation logic, easily causing internal circuit overload. Long – term overload can damage components and even cause fires. Meanwhile, devices connected to other ports may experience abnormal charging, damaging batteries and affecting device lifespan.

IV. Safety Risks: Over – Voltage Cases Caused by Parallel Connection of Cross – Protocol Devices

• Compatibility Issues of Cross – Protocol Devices Connected in Parallel: Compatibility problems emerge when devices of different brands and protocols are connected to a multi – port fast charger. For example, connecting a PD – protocol notebook and a QC – protocol smartphone to a multi – protocol charger can lead to power – allocation errors due to protocol differences.
• Over – Voltage Cases and Hazards: In laboratory tests, a PD – protocol notebook (65W demand) and a QC -protocol smartphone (18W demand) were connected to a charger. The smartphone’s voltage exceeded the safe charging upper limit by 0.5V. Long – term over – voltage can damage the smartphone battery and even cause explosions, while also affecting the notebook’s charging stability and battery life.

Multi – port fast – charging technology brings convenience to digital life, but its power – allocation mechanisms and safety risks cannot be ignored. Understanding these principles and risks helps us use fast – charging devices correctly. It’s advisable for users to prioritize products with mature power – allocation protocols and strict safety certification, and avoid deceptive devices to ensure safe, stable, and efficient charging.