Not every USB-C charger from the market is the same. Even though from the outside they might look the same, the power that these can provide depends both on the charger and the cable, and how they implement the USB-C Power Delivery standard.
Different type of USB-C cables
Even though all USB-C cables can provide power, not all support the same rates.
USB-C cables without Power Delivery
Don't implement Power Delivery
Can provide up to 15W
Work at 5V up to 3A
They're used for small devices, but can't provide enough power to charge a laptop
USB-C cables with Power Delivery
Can provide up to 100W
Work at 20V up to 5A
They're needed to charge laptops
USB-C cables with new Power Delivery Extension
Can provide up to 240W
Admits higher power: 24V, 36V or 48V at 5A
They need specific and certified cables that implement the extension
Multiple USB-C cables and chargers combinations
Although one charger or cable advertises that can charge at an specific rate, this doesn't guarantee that this rate can be achieved in practice.
The charger and cable negotiate power between each other
If one of them isn't certified or doesn't implement correctly the USB-C standard, the charge may:
Reduce
Not work
Cause damage to the device or the components themselves
For this reason, it is key to:
Use verified and quality cables and chargers
Make sure that both components support the power needed by the device
USB-C dockings and monitors with PD
USB-C dockings
The usage of USB-C dockings and its advertised PD capabilities can also be misleading:
A USB-C docking that advertises 100W may not always power those 100W, since the connections of the docking need power to work.
Part of the power is used for:
HDMI / DisplayPort
Ethernet
USB ports
The usage of high-resolution screens might reduce the power available to charge
Monitors with PD
Many monitors include USB-C with Power Delivery, but this doesn't guarantee that these can provide enough energy for the device.
Even though the monitor may provide 100W or even 140W, usually:
Only can provide between 60W up to 85W to the connected device.
Rest of power is reserved to:
The monitor's panel
Internal components
Integrated USB ports
In these cases, the device may:
Charge slowly
Not provide enough power to charge the device
Not work as the announced performance
Mobile chargers and laptop chargers
A very common error is to try to charge a laptop with a USB-C charger designed for mobile devices:
The majority of mobile USB-C chargers can only charge up from 18W up to 30W.
Some more powerful models can use chargers that can go from 45W up to 65W.
In the majority of the cases, these can not provide enough power to charge a laptop
This can make:
Very slow charge
That the device doesn't charge while it is in use.
That the device discharges while it is charging
Although the connection may be the same, this doesn't imply that the charger is the most adequate for the laptop
USB-C extensors
The usage of USB-C extensors is not recommended, specially for charging laptops:
May block the correct power negotation
May limit the charge or block it completely
Several are not ready for Power Delivery.
Recommendation:
Avoid using USB-C extensors or use only ones that are certified specifically for Power Delivery
Conclusion
To guarantee a stable and safe charge and that the performance of your device is correct:
Only use verified and certified USB-C cables and charges
Verify that both the charger and cable support the recommended power that the manufacturer recommends for your device
Don't assume that a mobile USB-C charger, a USB-C monitor or a docking can provide enough power for your device, even if the connector is the same.
Keep in mind that dockings, monitors and chargers with multiple connections share all the available power, and that in most cases, do not reach the minimum power to charge your device in real cases.
If your monitor, docking or charger do not provide the recommended power for your device, DO NOT USE THEM to charge your device and only use the original charger.
With this, you will avoid:
Slow or unstable charges
Performance loses
Erratic behaviours in your device.
Unnecesary risks for your battery and device.
In summary, even though the connector might be the same, not all the chargers and cables are the same. Make sure to choose them correctly to guarantee safety in your device.
