I’d be very happy with 236Wh per mile on a trip including speeds as high as 75mph, as that works out to 6.82km/kWh (the units we seem to use with our Japanese import cars).
To achieve that in a Nissan Leaf, you have to drive no faster than 90km/h (56mph). Going over 100km/h/62mph forces efficiency down to below 6km/kWh. I know this because I’ve had to drive disappointingly slowly in Leafs from work to make it home
Fuel consumption in cars has historically been measured at 90km/h, a kind of sweet-spot, as beyond that aerodynamic drag increases substantially to outweigh rolling resistance etc. (being related to velocity squared as already noted).
I imagine for peak efficiency, that optimum speed of 90km/h/56mph would still apply, even to a slippery shape like the Tesla. Clearly, there’s less drag with the Tesla, but that drag must still build up at a similar rate of increase (air being the same density etc.) unless there was some really special boundary-layer-separation going on (e.g. breaking though the sound barrier!)
So just to be clear, the efficiency of a Model 3 clearly beats a Leaf (more efficient motor(s) and less aerodynamic drag even at higher speeds), but I’m suggesting that the drag increases with speed at a similar rate, such that the minimum-drag cruising speed is similar for all vehicles.
-Alex
To achieve that in a Nissan Leaf, you have to drive no faster than 90km/h (56mph). Going over 100km/h/62mph forces efficiency down to below 6km/kWh. I know this because I’ve had to drive disappointingly slowly in Leafs from work to make it home
Fuel consumption in cars has historically been measured at 90km/h, a kind of sweet-spot, as beyond that aerodynamic drag increases substantially to outweigh rolling resistance etc. (being related to velocity squared as already noted).
I imagine for peak efficiency, that optimum speed of 90km/h/56mph would still apply, even to a slippery shape like the Tesla. Clearly, there’s less drag with the Tesla, but that drag must still build up at a similar rate of increase (air being the same density etc.) unless there was some really special boundary-layer-separation going on (e.g. breaking though the sound barrier!)
So just to be clear, the efficiency of a Model 3 clearly beats a Leaf (more efficient motor(s) and less aerodynamic drag even at higher speeds), but I’m suggesting that the drag increases with speed at a similar rate, such that the minimum-drag cruising speed is similar for all vehicles.
-Alex
Last edited:
