USB-C Hub with Power Delivery: Sizing the Charger
A hub that charges the laptop as well as expanding it is convenient, and it is also where most complaints originate. The charger rating decides everything.
Quick Answer
A hub with Power Delivery passthrough accepts the charger on one port and passes most of that power to the laptop while running its own ports. Expect roughly 85 to 90 percent to reach the laptop because the hub consumes some power itself. Size the charger above the laptop rating to compensate, and check the hub stated maximum, since many cap at 100 W input.
How Passthrough Works
| Stage | What happens | Typical figure |
|---|---|---|
| Charger output | Supplies the hub | 65 to 140 W depending on model |
| Hub overhead | Runs its own ports and chipset | A few watts to around 15 W |
| Laptop input | Remaining power for charging | About 85 to 90 percent of the charger |
| Maximum accepted | Hub input ceiling | Often 100 W |
Sizing the Charger
Match the laptop requirement first
Find the wattage the laptop expects, then add the hub overhead. A laptop wanting 65 W needs a charger of at least 75 W, and preferably 90 W or more.
Watch the cable
Power Delivery above 60 W needs an e-marked cable. A basic cable caps the link at 60 W regardless of the charger.
Beware the hub ceiling
If the hub accepts 100 W but you supply 140 W, only 100 W enters. Choose a hub rated for what you intend to use, or accept slower charging.
Charging while working hard
Under heavy load a laptop may consume more than the passthrough provides, and the battery slowly drains. Increase the charger rating rather than replacing the hub.
What Else Shares the Link
- USB data ports, which share the upstream bandwidth.
- Video output, which may reduce USB data to USB 2.0 in four lane mode.
- Ethernet, which competes with storage traffic.
Real-World Applications
- A single cable desk setup for a thin laptop.
- Charging a tablet while using a display and a card reader.
- A hot desk where the charger stays with the monitor arm.
- Travel kits where one charger serves everything.
Related Guides
For wattage behaviour without a laptop, read USB-C PD hub. For power budgets, see USB-C power hub. For the hub versus dock decision, start with USB-C hub or dock.
FAQ
Why does my laptop charge slowly through a hub?
The charger is undersized once hub overhead is deducted, or the cable is not e-marked for higher wattage.
Can I use the hub without a charger?
Yes for data, but the laptop will not charge and drives may not receive enough current.
Does passthrough work with any USB-C charger?
With any charger that supports Power Delivery. Older 5 V only chargers will not negotiate higher wattage.
Will a 140 W charger charge faster through a 100 W hub?
No. The hub ceiling limits what passes through.