Range reduction while using driver assist?

[Krlefkowitz]

Does using the driver assist drain the battery faster than manual driving? We are seeing a faster than normal battery drain on highway driving.

 

[BitJam]

Welcome!

I really don't think it makes a significant difference. The car uses about 20 kW (or more) driving down the highway. The computers are on when the car is on. They might consume a little more energy when working hard but probably less than 100 W more which is 0.5% of the energy used for moving the car.

Driving fast, extra weight in the car, falling rain, and use of HVAC will have more of an effect on your range. Especially driving fast. If you provide some numbers (like the watt-hours/mile consumed and the speed you are driving) then people can tell you if there is a problem with your car or not. Most likely the answer is "not". The EPA ranges given by Tesla are optimistic, especially for highway driving.

For example, increasing your speed from 30 mph to 70 mph can cut your range in half.

 

[Big Earl]

Does using the driver assist drain the battery faster than manual driving? We are seeing a faster than normal battery drain on highway driving.

We need more information about your driving behavior.

Autopilot isn't inherently less efficient on the highway. If you typically use Autopilot on the highway and drive manually on city streets, and you're wondering why your miles tick down more quickly than the miles you're actually driving, it's likely because of increased aerodynamic drag caused by driving quickly. Aerodynamic drag increases with the square of speed. You're going to get really poor range if you drive at 80 MPH compared to 65 MPH.

Compared to an experienced driver who practices "hypermiling" techniques, Autopilot can be less efficient on roads with lots of elevation changes (mountain and rural roads, for example).

 

[doghousePVD]

I find autopilot uses the brakes (loses energy) much more often than I do. When there variations in the traffic speed, I take my foot off the accelerator as soon as I recognise the slow down/red light, and so essentially never use the brakes on the highway. The autopilot maintains speed until much closer, then applies brakes.

If the highway is completely clear so the autopilot can always maintain the speed, there shouldn't be any difference in consumption. It may be better than me at maintaining constant speed than me.

 

[GtiMart]

We don't know if testing on the highway was done without autopilot. The sentence looks like highway consumption is higher, period. That is true, whether you use autopilot or not...

 

[Genie]

On a highway with light traffic I don’t think my right foot can be as efficient as the driver assist. in traffic I might be a tiny bit better more efficient adjusting to speed changes.

 

[BitJam]

I find autopilot uses the brakes (loses energy) much more often than I do. When there variations in the traffic speed, I take my foot off the accelerator as soon as I recognise the slow down/red light, and so essentially never use the brakes on the highway. The autopilot maintains speed until much closer, then applies brakes.

If AP is enabled and you see a slowdown or red light up ahead, have you tried reducing your speed with the right scroll wheel?

This works for me. I treat AP as an interactive driver assist, not as a driver replacement. AP is my favorite feature of the car. I use it for over 80% of my driving. But I no longer sit back and see how well the car do on its own. Instead I try to see how well we can do working together.