Electric-car range has become one of the industry's favourite big numbers. 500km. 600km. 650km. Occasionally something beginning with a seven. Useful numbers — but not necessarily the number you most need to know.
The test isn't the trip.
Most Australian range claims are based on a standardised laboratory test such as WLTP. That's valuable because it gives us a consistent way to compare one car with another. What it doesn't do is recreate your family heading up the Hume at 110km/h with luggage, air-conditioning, wind and a destination still a few hundred kilometres away.
Electric cars are generally less efficient at sustained high speed than they are around town. Aerodynamic drag rises sharply as speed increases, while urban driving gives an EV repeated opportunities to recover energy through regenerative braking. So the brochure number and the motorway number can be quite different.
A better number to remember.
Rather than obsessing over the biggest claimed range, look at efficiency — usually expressed as kWh/100km — and usable battery capacity. If a car has 75kWh available and is consuming 20kWh/100km on the motorway, simple arithmetic points to about 375km from full to empty under those conditions.
Of course, nobody sensible plans a road trip around arriving at zero. The useful travelling range is the distance between the charge level you leave with and the level at which you're comfortable stopping.
650km is interesting. How far it goes at 110km/h is more interesting.
Australia makes the question matter.
We have long distances, high motorway speeds, heat, headwinds and charging locations that can be a long way apart. That's why WattCar wants to test motorway range as part of the ownership story rather than simply repeat the official number.
We'll still publish WLTP because it's a useful common yardstick. We'll also tell you what happened when we drove the car in the conditions Australians actually use it in.
Use the official range to compare cars. Use real-world motorway range to plan the trip.
What we'll measure.
For WattCar testing, the interesting questions are simple: what efficiency does the car return at Australian motorway speeds, what usable distance does that imply, how much does weather change it, and how accurately does the car's own range prediction behave as the battery falls?
Because the number that matters isn't the one that gets the biggest type on the brochure. It's the one you can trust when the next charger is 80km away.