Hypermiling techniques?

[TXjak]

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.

I do it too. As for the legality, considering that the Tesla has no transmission to shift and the legal definition of neutral is likely to have some reference to a transmission, no problem. You are simply selecting N for No Regen.

John

 

[bhzmark]

I love it yes. N for No regen.

"Here is your ticket for driving in neutral" said no cop ever.

 

[Chris TX]

This is how I get above the rated range. The goal is to keel the kW to ~18 and the average Wh/Mi to less than 300. You CAN'T do this with cruise control, unless you are on a perfectly flat road. I take my right foot and just push the pedal down until it gets to just under 20kW. Then, I push my shoe to the side where it sticks. This doesn't work in sandals or dress shoes. On flat roads, this tends to get you ~65MPH. Going uphill, you'll slow down and going downhill, you'll go faster and faster. Let off the pedal a bit if you don't want to go over the speed limit. The flatter this line, the better:

Never let the gauge go into regen, unless you're going down a steep hill. Keeping it close to 0kW is best.

You might need to push it a little bit for safety, going uphill. Just watch your rearview mirrors for approaching cars.

The second thing is to put the steering in Sport mode. This actually takes up less power than Standard or Comfort.

Air the tires up to MAXIMUM. This is 50-51PSI. Just look at the sidewalls. Do one less PSI if they aren't warm.

Watch the outside temperature. If it's low enough, put the HVAC on fresh air, turn the AC off, and set the temp to LO. Anything above LO will kick on the heater if the outside temp is below 67.

Lastly, if you have air suspension, have it lower at 60MPH.

 

[bhzmark]

Never let the gauge go into regen, unless you're going down a steep hill. Keeping it close to 0kW is best..

Exactly. The best way to glide and avoid regen is to slide into neutral -- especially in a slight downhill grade where you can go forever.

Other things good tips too. Didn't know about the steering.

 

[robby]

The second thing is to put the steering in Sport mode. This actually takes up less power than Standard or Comfort.

Can you elaborate on or provide a source for this?

 

[jerry33]

Can you elaborate on or provide a source for this?

I keep my steering in comfort mode and it doesn't seem to affect Wh/mi enough to notice. I also think that putting the car in neutral is silly when you can accomplish the same thing with foot position on the accelerator pedal.

 

[Chris TX]

Can you elaborate on or provide a source for this?

In Comfort mode, the servo is working harder (using more power) to assist. When you put it in Sport mode, it uses less power and gives you a more direct feel of the steering. It doesn't make a big difference if you are driving straight (like most Texas highways), but any time you come to a bend or curve which causes you to turn the steering wheel, it will.

You might be able to capture this data using Visible Tesla. You can see the power meter pop up a little bit if you're sitting still, turning the steering wheel back and forth when you're in Comfort mode. As Jerry said, it's probably not a huge gain but when you're hypermiling, every bit helps

 

[GSP]

I keep my steering in comfort mode and it doesn't seem to affect Wh/mi enough to notice. I also think that putting the car in neutral is silly when you can accomplish the same thing with foot position on the accelerator pedal.

How can a human possibly keep wheel torque at exactly zero while the road goes slightly up or down, or when car goes around turns?

I guess I am assuming that the pedal must be constantly manipulated to counter various road and wind forces on the car to maintain zero torque.

Is there a single pedal position that always provides zero torque? If so, is it easy to find that position and hold it?

GSP

 

[Candleflame]

I do it too. As for the legality, considering that the Tesla has no transmission to shift and the legal definition of neutral is likely to have some reference to a transmission, no problem. You are simply selecting N for No Regen.

John

I love it yes. N for No regen.

"Here is your ticket for driving in neutral" said no cop ever.

Right... it IS actually illegal (depending on your jurisdiction I guess) to coast, that is to leave the car in neutral for longer than necessary. It does not matter if the car is manual, automatic or single speed (electric). This has nothing to do with having a transmission. If the drive shaft is not connected to the wheels you are coasting and in less control of the car. I.e. if you suddenly need to dodge or do an evasive manouver you would have to put the car back into Drive/shift into a gear before your gas/accelerator pedal does anything. That will cost you time in which you could have prevented a collision. Worst case scenario you will get some extra engine braking (manual/automatic) or regenerative braking (electric) from it in case of you deciding to stop the car rather than to evade. How someone is going to proof if you are coasting is obviously a different matter, but why not just control the regen with the accelerator pedal? That's what single pedal driving is all about!

 

[Chris TX]

How can a human possibly keep wheel torque at exactly zero while the road goes slightly up or down, or when car goes around turns?

I guess I am assuming that the pedal must be constantly manipulated to counter various road and wind forces on the car to maintain zero torque.

Is there a single pedal position that always provides zero torque? If so, is it easy to find that position and hold it?

GSP

If you play with the pedal, you'll find zero. It's not hard to do. For normal cruise hypermiling, I keep it at 15-18kW unless I'm going downhill. Then, I ease off the pedal until the meter goes to zero, and not into regen. Yeah, you can make regen low in the settings but if you get a steep downhill, you're going to need to hit the brakes.

Oftentimes, I wish the pedal could be replaced by a potentiometer. It could be engaged in place of cruise control and either manually disengaged or when the brake pedal is pressed. That would certainly help with the leg/foot cramps

 

[jerry33]

How can a human possibly keep wheel torque at exactly zero while the road goes slightly up or down, or when car goes around turns?

I guess I am assuming that the pedal must be constantly manipulated to counter various road and wind forces on the car to maintain zero torque.

Is there a single pedal position that always provides zero torque? If so, is it easy to find that position and hold it?

The energy gauge will tell you until your foot gets educated. It's really pretty easy, and after a while you barely think about it. It's really no different than keeping a constant speed with your foot.

Close is good enough--at least there aren't that many S85 owners that have a lifetime average of 250 Wh/mi, so my assumption is that any gains from using neutral are minimal**. Because the energy scale is logarithmic, there is little difference between zero and a bit of green or a bit of orange.

S60 owners should be able to do better, maybe S70D owners as well depending on their mix of city to long distance driving. (As far as I know, the second motor gives up some city range for additional long distance range.)

** No offense to anyone, but based on the number of people who swear by neutral, I'd expect there to be a good percentage who get far better results I do, because I really don't try all that hard (at least not compared to when I drove the Prius). I'd love to hear of additional techniques that help without compromising safety. (That extra second taken to shift out of neutral at 70 mph means you go another 100 feet into whatever trouble it was that you were trying to avoid--and it might take more than a second depending upon what your right hand was doing at the time.)

 

[bhzmark]

Brakes and steering still work in "no regen" mode. That gets you out of nearly all trouble. And without your rt foot having to feather the accel constantly hunting for zero, instead it can hover closer to brake pedal allowing for faster full on braking. Nothing unsafe about n mode at all. But if scares you, by all means don't use it. The efficiency difference is probably small -- approximately the amount of loss in regening some speed and then having to give it back.
Drivers who grew up with a stick and are used to driving either in neutral or with the clutch in on a stick are probably more comfortable with it.

 

[jerry33]

Unless you need to accelerate to get out of trouble. And even when braking if you're in D, regen starts slowing before your foot hits the brake pedal.

 

[bhzmark]

Faster doing full stop braking vs. Slower to accel while flicking gear shift back to d. Faster full on braking is much more useful to avoid worst case scenarios.

 

[Candleflame]

Brakes and steering still work in "no regen" mode. That gets you out of nearly all trouble. And without your rt foot having to feather the accel constantly hunting for zero, instead it can hover closer to brake pedal allowing for faster full on braking. Nothing unsafe about n mode at all. But if scares you, by all means don't use it. The efficiency difference is probably small -- approximately the amount of loss in regening some speed and then having to give it back.
Drivers who grew up with a stick and are used to driving either in neutral or with the clutch in on a stick are probably more comfortable with it.

This isn't about brakes and steering. It's about being as safe as you can probably be on the road. FACT is, that you loose regenerative braking power or engine braking when you are in neutral. FACT is, that you loose the ability to evade effectivly without being able to accelerate. FACT is, that it is illegal to coast.

Also driving in neutral or with the clutch depressed uses more fuel than keeping the car in gear. I don't know any driver who does this.

 

[bhzmark]

Only fact that is clear to me is that some people are scared of neutral and should not use it.

People who grew up driving a stick and know that cruising in the top gear and trying to accelerate will go nowhere and so you have to
1) depress clutch,
2) reach down between seats and downshift one, two or three gears,
3) release clutch while ,
4) depressing accel

will not be scared of having to
1) while hand is still close to steering wheel, flick back to D,
2) engage the Tesla warp drive accel pedal.

 

[ahimberg]

What recommendations are there for best mileage when going up/down steep hills/mountains?
(where its not possible to stay under 30kW, maybe there is a max speed target that isn't going to have too much wind adding on)

 

[bhzmark]

Pretend you are at the top of the hill with a zero battery left and you see a supercharger in the distance down the hill. Should you go down the hill coasting to try to get the supercharger or should you go down the hill slowing down your speed but capturing a percentage of that speed into regen and recharging the battery and then using that stored energy in the battery to power the car further along?

I think the answer depends on the speed at which the aerodynamic drag and rolling resistance at higher speeds exceeds the energy loss by recapturing the speed into the battery. I think I recall someone estimating that speed at being around 70.

So I would suggest coasting down the hill up to about 70, either by coasting with the car in neutral (if you can do so without feeling scared) or feathering the accelerator pedal to find 0 regen. If you start to exceed ~70 then apply more regen.

 

[jerry33]

What recommendations are there for best mileage when going up/down steep hills/mountains?

You try to use as little as possible going up, and then use regen to stay under or at the speed limit going down. There is some point (that no one has yet defined) when speeding down a hill where aerodynamic resistance will lose more energy than regeneration does.

Short and steep going up and long, gradual slopes going down give the best results--if it can be arranged (often not possible).

For rolling hills it seems to be best to get all the speed you can on the downhill and glide or low power as much as you can going uphill only using power to crest the next hill. This is a different strategy than the mountain descent mentioned earlier, but any bike racer can attest to getting the best speed with the least amount of energy using this technique.

 

[David_Cary]

This isn't about brakes and steering. It's about being as safe as you can probably be on the road. FACT is, that you loose regenerative braking power or engine braking when you are in neutral. FACT is, that you loose the ability to evade effectivly without being able to accelerate. FACT is, that it is illegal to coast.

Also driving in neutral or with the clutch depressed uses more fuel than keeping the car in gear. I don't know any driver who does this.

Huh? You might need to go back to engineering school. But either way, ICE and EV have very different characteristics here. But for ICE, just look up "pulse and glide" - hint - glide is in neutral or clutch in.

Now it does get complicated with newer cars that can cut the fuel on coasting but you still have more parasitic loses. Glide in neutral with ICE off can't be beat.