The Model S is equipped with either a 70kWh or 85kWh battery, which in the UK at least leads to a “typical” range of either 200 or 245 miles when fully charged. As with any car, there are various factors that impact what range you will actually achieve, which could be significantly less – or more – than those numbers.
To get an idea of what is reasonable in everyday driving, see how far you can really travel in a Model S.
Do you need to maximise your range?
For some Model S owners, driving carefully and efficiently becomes an integral part of the ownership experience, with great pride taken in achieving a very low Wh/mi figure for each journey or over the lifetime of ownership of the car. However, it’s worth remembering that, since most journeys are much shorter than the car’s range and most owners recharge every night at home, 99 times out of 100 you will not have any need to worry about driving efficiently. You’ve bought a car with the most responsive, rapid and effortless powertrain in the world, so don’t forget to enjoy it!
Even if you are on a long journey then, depending on your charging options, you may still not need to worry about your efficiency. Superchargers are so fast that if you’re following a route with superchargers along it then the optimum strategy for getting to your destination most quickly is actually to drive fast and charge for longer – you will save more time by increasing your speed by 10mph (assuming it is safe and legal to do so) than you would save from a shorter charge time at the supercharger.
But if you’re taking a long trip and the route is not supercharger-enabled, then you may find yourself needing to take car with your range; in which case, read on.
Factors that impact Range
The laws of physics make it inescapable that for a given journey, at a given speed, there is a certain minimum amount of energy that you will consume, and no tricks or techniques can improve on that. However there are things that you can do to increase your range, and with recent software updates the car now has useful tools built in that help you predict and monitor your range as you drive.
The main factors that impact your range are:
- Weather/Road Conditions
- Driving Style
The biggest factor by far in your driving efficiency is speed. Whenever the car is moving you are consuming energy to fight against wind resistance, and the energy needed for this per mile travelled increases roughly in proportion to the square of your speed – at 80mph it takes four times as much energy per mile to defeat wind resistance than it does at 40mph.
If you want to extend your range, slow down.
If you find that you tend to speed up without noticing then engage cruise control. However, the cruise control system is not designed to maximise efficiency so if you are conscientious you can drive more efficiently without it (see below)
Driving uphill uses extra energy, and there is nothing you can do to change this. It doesn’t matter if you drive up the hill slowly, or quickly, the energy cost of the climb is the same. Driving downhill allows you to reclaim a lot of this energy but some will always be lost so any journey in hilly terrain will always use more energy overall than an equivalent journey on the flat.
Heating/AC and other Electrical Consumers
The heating/AC system in the car can draw a significant amount of power from the battery, especially when warming up the car from cold. You can increase your range by pre-warming/cooling the car while plugged into the mains before you start your journey and by turning off (or turning down) the system while on the move.
The Model has a “range mode” which reduces the power of the heating/AC system.
The energy requirements of all the other systems in the car (headlights, audio & nav system, etc) are so small as to be basically irrelevant so there is no advantage to driving in silence, with satnav disabled, or with the headlights turned off.
Weather / Road Conditions
Bad weather tends to lead to reduced range, and there’s not much you can do to combat this other than pulling over and waiting for the weather to change.
For more information see this article.
Although many of the energy costs of travelling are fixed and unavoidable, there are ways you can adjust your driving style to help your range.
Avoid using the brakes
Whenever you press the brake pedal you are wasting energy by turning it into heat in the brake pads that you can’t ever get back. Drive carefully, maintain distance from cars in front, and try to anticipate the need to slow down so that you can avoid using the brake pedal as much as possible.
Aim for 0kW in the power gauge
The battery, drive inverter and motor of a Model S are pretty efficient, but whenever you draw power from the battery and use it to propel the car there are heat losses. And whenever you regeneratively brake and use the regained energy to charge the battery there are also heat losses. So for maximum efficiency you should aim to draw as little energy as possible from the battery, and also return as little energy as possible to the battery. That means driving as close to the 0kW point on the power gauge in the instrument cluster as possible.
For example, allow yourself to slow down as you climb a hill but speed up (coasting) on the way down the other side. And if you need to slow down because of traffic, or a junction, then regeneration is better than using the brake pedal but coasting to a stop is even better than regeneration.
As discussed earlier the biggest contributor to energy usage is speed, and at high speeds this mostly derives from wind resistance. Some owners combat wind resistance by driving close behind another large vehicle such as a truck, which places the Model S in the area of low pressure air created behind the lead vehicle.
If you drive very close behind a vehicle in this way you can make very considerable energy savings (around 20% or more). However, to get a significant effect you generally need to be nearer to the vehicle than the recommended safe stopping distance, which means that this technique is not recommended for safety reasons.