Explanation
When you see "50 kW" or "150 kW" on a charger, that number tells you how quickly energy is being delivered to your battery right now. Think of it like water pressure: a higher kW number means energy is flowing faster, so your battery fills up sooner. A 7 kW home charger adds roughly 40 km of range per hour, while a 150 kW fast charger can add 200 km in about 20 minutes.
You will see kW on the charger screen during a session, in your car's dashboard while charging, and in the charging app's session details. The number usually starts low, ramps up, and then tapers off as your battery gets fuller. This is normal and controlled by your car's battery management system.
The most common mistake people make is confusing kW with kWh. kW is how fast energy flows (power). kWh is how much energy you received in total (quantity). A 50 kW charger running for one hour delivers 50 kWh of energy.
For technical specifications, see U.S. Department of Energy AFDC.
Where you'll see this
- On the charger screen
- On your car dashboard
- In charging network apps
Common confusion
People constantly mix up kW and kWh. kW is the speed of charging (power), kWh is the amount of energy delivered or stored.
Example
A Tesla Model 3 can charge at up to 175 kW on a DC fast charger, but a home wallbox typically delivers just 7 kW or 11 kW.
Related terms
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From Finn, engineer: Understanding charging terminology helps you troubleshoot faster at the charger. These definitions are based on industry standards and our consulting work with automotive manufacturers.
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