Kilowatt-hour (kWh)
A kilowatt-hour (kWh) is the standard unit of energy used to express the capacity of an electric vehicle's battery. It tells you how much energy the battery can store and, by extension, how far the vehicle can travel on a full charge.
How It Works
One kWh equals one kilowatt (1,000 watts) of power delivered continuously for one hour. Think of it like the "fuel tank size" for an EV — a larger kWh number means more stored energy and generally more range.
EV batteries have two capacity figures: gross capacity (the total energy the cells can physically hold) and net capacity (the usable portion available for driving, after the manufacturer reserves a buffer to protect battery longevity). Net capacity is typically 90–97% of gross.
Why It Matters
Battery capacity in kWh is one of the most important specifications when comparing EVs. It directly influences range, charging time, vehicle weight, and price. A 60 kWh battery will generally travel further than a 40 kWh battery in the same vehicle, but it will also take longer to charge and add weight.
Understanding kWh also helps you interpret charging speeds: if a charger delivers 150 kW and your battery holds 75 kWh (net), it would theoretically take 30 minutes to charge from empty to full — though real-world charging slows down as the battery fills.
Common Values
- Small city cars: 25–45 kWh
- Compact/mid-size: 55–80 kWh
- Large SUVs and premium: 85–120 kWh
- Energy consumption: 14–25 kWh per 100 km depending on vehicle size