# Forums

## Energy-efficient driving

I am currently experimenting with ways how to drive my Tesla as energy-efficiently as possible, and I have found a way where preliminary results show a 10% reduction in consumption.

Story: I currently have a loaner, provided by the fantastic Denmark Tesla team, when my 12-V Battery malfunctioned for the 3rd time in 3 weeks - they actually transported a loaner 400 miles to Stockholm and brought down my car for repair - WOW!!

This loaner, though, consumes about 10% more energy than my proper car with identical trips, identical settings and, as far as I can see, identical driving. Because of an imminent long haul this concerned me very much, so I started to think of ways of bringing down the consumption. I got the advice from a Tesla man: drive it as you would drive an ICE.

OK, fine. I have developed a style of driving with ICE:s that invariably beats their own consumption figures (and we all know that they are the "optimal" ones anyway). It is quite easy - roll the car in Neutral as much as circumstances allow.

I tried this with the loaner, and it immediately yielded really good results - minus 10%, from 310 Wh/mile to 278 Wh/mile in 40 degrees F.

The Tesla is built with such a small wind and rolling resistance so that these 2 factors coupled with the huge mass makes the Tesla roll "for ever", especially in a down-slope. If there's just a small decline it doesn't even lose speed.

The gearbox is so well-made that I learned in less than 2 minutes how to change back and forth between Drive and Neutral without anyone noticing anything.

So, if you free-roll and want to lose speed, put it in Drive and engage re-gen. If you want to keep the speed or increase it, just put it in Drive and - well, drive.

The Cruise Control doesn't do this well - it constantly gives small "puffs" of energy and then brakes, for instance when you reach a small hill, and the re-gen cannot be 100% efficient, so you lose more than you gain, whereas, if the hill is small enough, you just roll over it in Neutral or you see it coming and accellerate slightly BEFORE the hill and roll down after it (never accellerate uphill, if it can be avoided).

This car has such eminent rolling features that this can be done without at all disrupting the traffic flow, if applied intelligently (mostly meaning rolling downhill, but also anticipating a traffic jam or light).

I called Tesla and asked them if this could in any way, shape or form damage the car (I am driving a loaner, and I am much more careful with other people's properties than with my own), and the answer from the Danish SC was an unequivocal NO.

My lifetime average consumption (incl. the multiple showing-off accellerations in the beginning - I am only human...) with my proper car is 289 Wh/mile, with the temp has varied between 29 F and 50 F. Applying the free-roll system, I think I will get it down to 260 or thereabouts. Will keep you posted.

Would be interesting to hear, if anyone else has tried this and their experiences.

Robert

Brian H | November 3, 2013

Good ideers.

It's the "goose pedal", btw.
;p

wufucius | December 31, 2013

I like to coast in neutral too, however you need to press brake before you can shift back to drive right? Is there any way around that? It is somewhat inefficient to need to do that if i want to speed up.

robert | January 1, 2014

@wufucius

No, you don't, absolutely not. That would make coasting impossible. Just use the middle finger of your right hand to go back and forth between drive and neutral, matching the speed with your foot when going to drive. Only if you stop the car do you have to press the brake.

jjaeger | January 1, 2014

That sounds exactly like how I drive, except I don't have to use my middle finger :-) Just the accelerator.

robert | February 7, 2014

Bumped

Tanchico | February 7, 2014

Robert, thanks for the bump. I'd missed this thread earlier. Not just an interesting collection of exchanges but entertaining as well.

One question I had about halfway through this thread… how are you able to compare driving styles and eliminate all other factors? I’ve tried this but the efficiency differences with varying temperatures and wind conditions seems to be much greater than my change in driving style. We’ve had anything from -12°C down to -28°C. Even the starting temperature of the battery seems to have an impact. At anything less than -10°C and I seem to regain some of the dercrease in potential from lower temperatures as the battery warms, this makes the first leg of my commute apparently more efficient than the latter. I’ve read that the battery has as little as 70% of its rated potential below -15°C.

robert | February 7, 2014

@Tanchico

The answer: I cannot, at least not scientifically. However, since my commute is basically the same (home-school-work and vice versa) and is about 35 miles and undertaken at the same time every day, and since the car starts at the same temperature every morning (heated garage) I can spot tendencies after a while, and that I do.

Car t man | February 8, 2014

The car's menu should be expanded to allow something like going into coasting, if you let off the pedal quickly, while using regen if you let of slowly.

Or a button for coasting. Smartly using coasting will increase efficiency.

jkn | February 8, 2014

Pedal should have coasting region between accelerate and regen wide enough to easily keep foot in. Width of it could be user adjustable.

hillcountryfun | February 8, 2014

Agreed and also mentioned as a possible enhancement in v6.0: alter cruise control such that highway speeds eliminates regen in favor of coasting.

SamO | February 8, 2014

Maybe Tesla can upgrade to "smart pulse mode" which will allow you to maintain a range of speed (say 5-7 mph) and do so efficiently, by using GPS and maps to anticipate elevation changes.

jai9001 | April 27, 2014

bump

christinawang1990 | June 16, 2015

Dear Robert,

I just posted my first thread:
http://my.teslamotors.com/forum/forums/i-got-my-energy-consumption-down-...