Your USB-C monitor does not charge your laptop usually because the monitor's USB-C port does not supply enough Power Delivery wattage, or the cable and laptop port do not support charging. Only USB-C ports with Power Delivery can send power to a laptop, and the port must provide as much power as your laptop needs, using a cable rated for it.
Why this happens
Charging a laptop through a monitor relies on a feature called USB-C Power Delivery. Several links in the chain must all support it:
- The monitor must have a USB-C port that outputs power, not just video and data. Many monitors have USB-C ports that only carry the display signal.
- The power the monitor supplies must meet or exceed what your laptop draws. A monitor that delivers 65 watts may not fully power a laptop that expects 90 or 100 watts under load.
- The cable must be a full-featured USB-C cable rated for the required power. Charge-only or thin cables can fail to negotiate high wattage.
- Your laptop must accept charging over USB-C. Some laptops only charge through their barrel connector.
Is this normal?
Yes, it is a common setup mismatch rather than a fault. USB-C ports look identical but vary widely in what they support, so many monitor and laptop combinations simply are not compatible for charging.
Does it cause any problems?
The main issue is that your laptop may slowly drain even while connected, especially during heavy use, because the monitor cannot supply enough power. Video and data over the same cable still work normally.
How to fix or check it
- Check the monitor's specifications for a USB-C port that lists Power Delivery and a wattage figure, such as 65W or 90W.
- Compare that wattage to your laptop charger's rating. If the monitor supplies less, expect slow charging or none under load.
- Use the USB-C cable that came with the monitor, or a certified full-featured cable rated for 100W, not a phone charging cable.
- Plug into the correct port. On the monitor use the USB-C port marked with power or a laptop icon, and on the laptop confirm the port supports charging.
- Update your laptop's firmware and the monitor's firmware, since some models need updates for Power Delivery to work reliably.
- If the monitor cannot supply enough power, keep using your original laptop charger alongside it.
Frequently asked questions
How do I know if my monitor's USB-C port charges a laptop?
Look in the manual or specs for the words Power Delivery and a wattage number. A power or laptop icon next to the port is another clue.
Why does my laptop charge but slowly through the monitor?
The monitor supplies less power than your laptop needs, so under heavy use the battery drains faster than it charges, giving a slow or negative charge.
Does the cable matter for USB-C charging?
Yes. A cable must be rated for the power level, ideally 100W and full-featured. A charge-only or low-rated cable can block high-wattage charging.