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Difficulty: MediumLaptop Power Systems and Battery Management

A field technician is troubleshooting a corporate laptop connected to a universal USB-C docking station. The user notes that while external monitors and peripherals operate correctly through the dock, the laptop battery gradually drains during heavy usage despite being plugged in. When using the original manufacturer AC adapter, the battery charges normally. Which TWO of the following best explain this behavior and identify the appropriate solution? (Select TWO.)

  1. The USB-C dock is supplying a Power Delivery (PD) profile with lower wattage than the laptop consumes during peak workloads.Answer
  2. Connecting the laptop to a dock or AC adapter rated for the full required Power Delivery wattage will prevent battery discharge under load.Answer
  3. C
    The technician should perform multiple deep discharge cycles down to 0% to recalibrate the Lithium-ion battery charge controller.
  4. D
    Any physical USB Type-C port automatically supports maximum Power Delivery wattage without requiring chipset contract negotiation.
  5. E
    Updating the DisplayPort Alt Mode driver on the laptop will increase the electrical wattage delivered through the dock cable.

Answer

The battery drains because the USB-C dock supplies lower Power Delivery wattage than the laptop's peak power consumption, and using a power source rated for the full required wattage resolves the issue.
The battery drains while docked because the docking station provides lower Power Delivery wattage than the laptop consumes during peak operations, forcing the system to draw supplemental energy from the battery. Providing a dock or adapter that meets the laptop's full Power Delivery specification ensures sufficient power for system operation and battery charging.

Step-by-Step Solution

1
Analyze the reported power symptom
Peripherals work, but the battery drains under heavy load when plugged into the dock, whereas the original AC adapter charges normally.
This indicates that data connections and low-level charging function, but total available wattage from the dock is lower than peak system power draw.
2
Evaluate USB-C Power Delivery negotiations
USB-C charging relies on Power Delivery (PD) negotiation between the power source (dock) and sink (laptop).
If the dock supplies less power than the laptop requires at peak performance, the laptop draws the remaining required power from its internal battery.
3
Determine the corrective action
Connect the laptop to a power source or docking station rated for the full wattage specification.
Providing adequate Power Delivery wattage satisfies system load demands while simultaneously charging the internal battery.

Key Concept

USB-C Power Delivery Wattage Negotiation and Battery Supplementation
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Topics

Laptop Power Systems and Battery Management

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