Hypermiling techniques?

[Cottonwood]

The next time I descend from the Eisenhower tunnel to Silverthorne SpC I'm going to try an experiment. Over several trips, allowing cruise control to hold 60-65 mph down the long, steep grade using regen, I have reliably added about 2kWh and six Rated miles to the battery. Cottonwood has driven the route even more frequently than I: his experience is consistent with mine. I hypothesize that if I join the trucks in the right lane driving, say, 35mph while using regen to hold speed, I should see a significant increase in the energy I put back into the battery, due almost entirely to reduced aerodynamic losses. I may get a chance to try it this week; will report back.

That will be a good experiment, but I thought "Test Pilot Stevezzzz" would go all out and try coasting down that hill. Enquiring minds want to know whether the coasting terminal velocity is over 100 mph or not...

All kidding aside, yours is a much safer experiment and just as informative. I bet you gain a couple of extra rated miles.

 

[evp]

That will be a good experiment, but I thought "Test Pilot Stevezzzz" would go all out and try coasting down that hill. Enquiring minds want to know whether the coasting terminal velocity is over 100 mph or not...

My bet is that he goes off the edge before he reaches 100 mph. Or maybe he'll be the first person to test the effectiveness of the runaway truck ramp with a Tesla. In either case, let me get up on the hill with a movie camera before he starts.

 

[stevezzzz]

My bet is that he goes off the edge before he reaches 100 mph. Or maybe he'll be the first person to test the effectiveness of the runaway truck ramp with a Tesla. In either case, let me get up on the hill with a movie camera before he starts.

Let me find my crash helmet and I'll meet you up there...:biggrin:

If somebody wants to do the analysis, my recollection is that regen never exceeds about 35kW while holding 65mph down from the tunnel. How much more aero drag would that 35kW overcome?

 

[fadkar]

4. Accelerate as slowly as possible.
5. Reduce speed when going uphill.

I consider accelerating slowly, and going slow uphill as "driving as slow as possible"

 

[AmpedRealtor]

The reason I'm pointing this out is because many people tend to believe that because regen is not 100% efficient it should be avoided. It is the wrong thing to take away from this. Regen is the one thing that makes EV so efficient.

I read somewhere that regenerative braking adds about 30% to the range of an EV versus not having it at all.

 

[jerry33]

I read somewhere that regenerative braking adds about 30% to the range of an EV versus not having it at all.

Basically it's Gliding* > Regen > Friction brakes. The additional range you get with regen and gliding depends on a wide variety of things such as traffic, stop lights, and terrain.

* I prefer the term gliding to coasting because coasting implies neutral. Gliding is done in D using the accelerator pedal.

 

[billarnett]

My bet is that he goes off the edge before he reaches 100 mph. Or maybe he'll be the first person to test the effectiveness of the runaway truck ramp with a Tesla. In either case, let me get up on the hill with a movie camera before he starts.

I haven't been there in a while but I would be willing to bet that it would be no problem at all for a Tesla to go 100 mph on that stretch if there was no traffic. Except for the cops, of course

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Does anyone have any data about the effects of suspension height on efficiency/range? Intuitively, it would seem that running at the LOW setting would help a little.

 

[AmpedRealtor]

* I prefer the term gliding to coasting because coasting implies neutral. Gliding is done in D using the accelerator pedal.

Agreed and I'll start using that term as well.

 

[brianman]

horse powers

I like this phrase.

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It is probably also the case the the minimum energy speed is slightly higher in very hot or very cold weather as the constant non-motor power is higher.

Also, does anyone know whether it's better to use the A/C or open the windows on a mildly hot day?

Keep the windows closed and use the climate control: opening windows ruins the car's aerodynamics (notice how much louder it gets from the wind noise and buffeting when you open windows? that's energy lost to the atmosphere).

I believe that's actually Tesla's recommendation, too, though I don't remember where I read it.

And for very hot weather, take off some clothes. And if you want even more efficiency, leave those extra clothes at home and also go to the restroom to rid yourself of some of that weight as well. Also, work out every so often so you generally weigh less.

 

[stevezzzz]

And for very hot weather, take off some clothes. And if you want even more efficiency, leave those extra clothes at home and also go to the restroom to rid yourself of some of that weight as well. Also, work out every so often so you generally weigh less.

There's an old saying in general aviation: "The best way to improve the performance of a light plane is for the pilot to lose a few pounds." :biggrin:

 

[bxr140]

Does anyone have any data about the effects of suspension height on efficiency/range? Intuitively, it would seem that running at the LOW setting would help a little.

No data from me.

But...for non-aerodynamic cars, lower is better. For very aerodynamic vehicles with [specifically] aerodynamic under bellies, higher is actually better. Whereas the lower height minimizes the total flow volume under the car (and thus, the amount of flow that can dirty up), the higher ride height pulls the car farther out of ground effect and can minimize the overall dirty flow (and thus, drag).

From a practical perspective, the later only works for REALLY aero vehicles. All indications suggest the model S is still in the first category.

 

[hingisfan]

Is shifting in and out of neutral an ok thing to do? I have a couple nice long gradual hills on my regular drive to work and I find it easier to go to N and then back to D at the bottom of the hill....but I don't want to do this if there are any issues being caused by it.

 

[billarnett]

There's an old saying in general aviation: "The best way to improve the performance of a light plane is for the pilot to lose a few pounds." :biggrin:

I weighed 265 lbs when I ordered my Roadster. I weighed 175 when I took delivery two years later . Holding steady since then but it's a constant struggle

 

[jerry33]

Is shifting in and out of neutral an ok thing to do? I have a couple nice long gradual hills on my regular drive to work and I find it easier to go to N and then back to D at the bottom of the hill....but I don't want to do this if there are any issues being caused by it.

As far as is known, there aren't any issues, but it's always seemed rather silly to me because it's illegal in many jurisdictions, and it's just as easy to keep your foot on the accelerator pedal. After a bit of practice, you don't even have to think about it.

 

[David99]

I weighed 265 lbs when I ordered my Roadster. I weighed 175 when I took delivery two years later . Holding steady since then but it's a constant struggle

That's awesome! Congrats! What is your calorie hypermiling trick?

 

[billarnett]

That's awesome! Congrats! What is your calorie hypermiling trick?

It's just like hypermiling in a car: incredibly painful. There's no secret trick. The ONLY thing that actually works is to eat less and exercise more.

 

[bhzmark]

Is shifting in and out of neutral an ok thing to do? I have a couple nice long gradual hills on my regular drive to work and I find it easier to go to N and then back to D at the bottom of the hill....but I don't want to do this if there are any issues being caused by it.

Hybrid owners have been doing that all the time to hypermile. That is the easiest way to hypermile and conserve energy without loss to regen at moderate speed.

And being in neutral gives certainty rather than feathering the pedal to go in and out of the regen/accel points on either side of gliding.

Re being a supposed violation of the law to drive in neutral: who cares? If you are remotely coordinated and can put the car back in drive when needed there is no safety risk and no risk of being found to violate the law.

Being in neutral maximizes preservation of momentum and not losing it to either braking with regen inefficiency or using excess power that will just have to slowed again with the less efficient regen braking, or worse, brake pad braking.

Gliding in neutral up to stop lights or other stopping or slowing points is a great hypermiling technique.

Someone who is behind you and wants to race up to a stoplight just in order to make a bunch heat and brake dust (or only somewhat better: convert some kinetic energy into electro-chemical energy with some regen) when they get there may sometimes be annoyed.

 

[BerTX]

Duck, bhzmark! :scared:

 

[jerry33]

Re being a supposed violation of the law to drive in neutral: who cares? If you are remotely coordinated and can put the car back in drive when needed there is no safety risk and no risk of being found to violate the law.

Except if you need to press the accelerator in a hurry. Neutral doesn't buy you anything.

 

[bhzmark]

Except if you need to press the accelerator in a hurry. Neutral doesn't buy you anything.

While foot moves to press on accel, finger reaches over and engages drive.

For those who are remotely coordinated putting the car in drive when needed is easy. Been doing it for years. The Tesla/Mercedes steering column shifter make that even easier.

And 99% of the time the safety events require brakes rather than accel. Coasting in neutral allows foot to hover over brake pedal for even faster application of full panic braking.

But for those who try it and don't like it and are scared or uncertain of coasting in neutral shouldn't do it.