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Driving for better mileage

Driving for better mileage

I have an 85kW battery. At this point it looks like I would get about 150 miles per charge. So I think it's high time that I start learning some coasting techniques.

I have all of the settings as "energy saving" as possible. So far the lowest average energy usage that I've gotten was somewhere around 380kWh. I understand that that's terrible, and it's due to my lead foot. I'm trying to get better.

Does anyone have any tips or tricks that they've found that works with them? I've googled, and volkerized, just wanted to go straight to the source to see if there are any secrets that I'm missing.

Thanks

gibbs | November 23, 2013
jonlivesay | November 24, 2013

Assuming you haven't had your car long. Give it time you and a driver will calm down and you will use less energy. If not at least you got 150 miles of fun each time.

frankviaje | November 24, 2013

I have had my car six weeks, and I average about 235 miles per charge. But, I drive conservatively (in the MS), rarely exceeding the posted speed limit with a mix of city and highway driving. I read an interview with the guy who supposedly set the record for single charge mileage in an MS: 725 miles. He stated that he drove a steady 18 MPH. Though that is not practical, it gives us all a marker for which to strive.

gill_sans | November 25, 2013

Imagine you have a loosely covered full pot of soup sitting in your trunk. That will slow down your accelerations and brakings and you'll get down around 250 Wh/mi for energy consumption, which is 4 miles per kW, i.e., closer to rated range (maybe even more) of your 85kW battery.

The lowest I've ever driven is around 250 Wh/mi when I was not in a hurry to get anywhere soon. You can't drive on a freeway around here, though, and use less than around 360 Wh/mi because everyone drives 65 to 75mph or faster.

gill_sans | November 25, 2013

Typo: Should've been "4 miles per kWh."

DTsea | November 26, 2013

Use cruise control. After stop lights let the cruise bring you back to the previous speed too.

gibbs | November 27, 2013

Yesterday, I drove below posted speed limits, and I still used 25% more than rated range (versus the 100% I was getting before). Ugh...I'm supposed to be going on a road trip on Saturday. Not sure if I can make the 180 miles.

My wife will snap if we have to drive 18 mph. :(

I delivered wedding cakes, and I drove more reserved than that. I'll try envisioning soup, and leaving on cruise control.

Thanks

paulkva | November 27, 2013

A few tips I've seen scattered around the forums, both here and at teslamotorsclub.com:

If it's cold where you are, favor the seat heaters over the forced-air heat. If you must use forced-air heat, try it with AC off and recirculate on.

Somewhere in settings, there's also a "range mode" option which supposedly makes the heat/AC a little more efficient.

Favor regenerative braking over the brake pedal as much as possible. (Set regen to "standard" if it's on "low.")

Pre-heat the car while it's still plugged in / charging, if possible.

Try to finish your recharging cycle as close to the time you plan to leave as possible. (This pre-heats the battery.)

Is it 180 miles round-trip or each way? Do you have a place to charge at your destination?

I was able to stay mostly below 300 Wh/mi when it was warmer out, but now I'm closer to 310-320. When it's really cold out and I have to use the heat, it's more like 350.

gibbs | November 28, 2013

180 miles one way. It's my wife's family, so I hope they let me charge there. I'll make sure before I leave.

I have all of the range extender settings turned up as high as possible. Of course, my wife and two young kids are going to want the heat on.

I'm going to drive very conservatively. If I can't get 180 miles out of the car that's rated for 260/300, I going to be a very sad panda.

gibbs | November 29, 2013

I tried using the "pot full of soup" method, and it worked out pretty well. Also, charging the battery worked wonders. I was getting around 300 Wh/mi. There was a stretch where I was averaging around 4m/kWh. But with all of the hills in my area, I ended up getting around 3.5m/kWh.

So now, I'm thinking about the end game.

I'm guessing that it's easier to get a decent m/kWh while traveling on the highway. So what kind of numbers should I be aspiring to acheive? Is it still 4mi/kWh?

tes-s | November 29, 2013

I have found leaving right after charging the battery has the biggest impact. In cold weather I find I am in the 325wh/mile range if I start out after charging - sometimes lower, sometimes higher.

When it is 60 degrees out and not using much HVAC, I get around 275 wh/mile.

I know others get better - but I just drive, and probably not all that well.

Theresa | November 29, 2013

I consistently drive a 201 mile trip and have had the S for a year. Even in cold weather i have range left when I arrive. My technique is to hold the accelerator as steady as possible and let my speed vary a bit. Of course I am always paying attention to traffic around me and adjust accordingly. Half of my trip is 65 mph speed limit and the rest is 55 mph. I have not had much difference in results using the range settings. I keep the car comfortable but a bit on the cool side.

Theresa | November 29, 2013

Also as tes said try to prewarm the car and leave as soon as the charging is done.

Devin B | November 29, 2013

When you are accelerating try and keep it under 30kw and always stay under 60kw unless going uphill and you will do better.

Jamon | November 29, 2013

Hey gibbs - I'm worried about your charging situation. If you deplete most of the battery on the way to your inlaws, you really need to make sure you have a plan to recharge for your trip home. Do they have a NEMA 14-50 outlet, or would you use 120V? If the latter, that would take you days to recharge (if they give you access to it). Will you have access to a Supercharger on your route? Have you identified other high power charging options near your destination (campgrounds, Nissan dealers, chargepoint stations) to help you charge faster if necessary?

I just don't want you to get stranded with your inlaws longer than necessary :)

robert | November 29, 2013

See coasting technique - I just bumped it from page 23 or so.

Robert

gibbs | November 29, 2013

Good question, Jamon. They actually have 220V. So we should be good.

I got nervous when I did research. There's a Nissan dealership about a mile away, but the charger takes **SIX TO EIGHT HOURS** to fill up a Nissan Leaf.

That would have made me really sad.

Pungoteague_Dave | November 29, 2013

The coasting techniques referred to on this forum are not a new invention - they are the same basic hypermiling techniques that have been employed by hybrid drivers for over a decade. What @robert has described here is commonly known as pulse-and-glide in the hypermiler world. Just be careful - we don't want to be labelled as the nut cases that many Prius drivers have correctly been labelled. There's a reason people hate to be behind the average (not all) hybrid car. I regularly drive my S85 well below the speed limit when pushing or matching range to a destination, but only where it will affect no one else (except my now perpetually PO'd wife).

gibbs | November 29, 2013

@robert, I just found your post "Energy Efficient Driving". Very interesting stuff.

So that was almost a month ago, so I'd like to know if everything is coming along. Since I don't do well with large posts, I want to make sure that I have everything right (compiled with information with this thread):

  • Turn regen up to max
  • When going downhill, put the car in neutral
  • If I need to slow down, put the car back in drive, so regen kicks in (from blocks away, if possible)
  • Speed up down hill, never uphill (if possible)
  • Make pretend there's a full pot of soup in the car. Try not to spill said soup.
  • Time the battery charge to finish right before use

Is there anything that I should add? Right now, I know that I have a lot to concentrate on. But it's very comforting that I see that you can go highway speeds, and still get great mileage.

I'm going to go practice right now. ;)

robert | November 29, 2013

@gibbs,

the "soup advice" wasn't mine, but, yes, those are the essentials.
Add this one: try to read the traffic flow, so you can slow down while in Neutral also on flat ground or uphill, for instance a red light or STOP sign some distance away, that is, coasting so that the car stops at the light by itself, the very last by regen, while not irritating those that insist on full speed and acceleration towards the light, and then standing on the brake just prior to it.

Good luck!
Robert

David Trushin | November 29, 2013

Check on the 220 you may need a different adapter unless there is a 14-50 connector. Also look for chargepoints along the way just in case. 55 in cruise seems to work pretty well.

DJay | November 30, 2013

Rather then put the car into neutral can't the same result be achieved by modulating the accelerator pedal so there is no energy being consumed or being regenerated while going down hill. It's very easy to do.

Panoz | November 30, 2013

Interesting thread...the OP visiting in-laws that "have 220". I was thinking about that...most every home I know has 220v for a dryer, but it isn't accessible. It's either too far away or not even on the same floor. And I thought I read where you're not supposed to use extension cords for charging a Tesla. Sooo what does a Tesla owner do when visiting out of town? Do you carry a 100-ft 220v extension cord?

DJay | November 30, 2013

I have a 15 foot 50amp extension cord that I use when I go to daughters house. It works just fine. There are past discussions on this forum on using correct extension cords and making adapters which are easy to do, but must be wired correctly. The adapter thread has photos and wiring instructions for each type of outlet. It took me about 15 minutes to make the adapter.

shs | November 30, 2013

At the marina/boatyard where we keep our sailboat, they have a 240V 50A (NEMA 6-50) outlet and an alarmingly thin (12 gauge?) 70 foot extension cord that is used with welders repairing boats in the yard. That same extension cord just makes it to the parking lot and we have successfully charged the MS overnight several times using this extension cord. The first time I carefully varied the amperage and found that I could charge at 26 amps without losing more than 10V to the resistance in the cord, a perhaps somewhat arbitrary rule of thumb. I also check all along the cord for heating, but so far have not found a problem. At some point I will no doubt invest in a heavier duty cord for use at the marina.

For charging at friends houses, I bought 27 ft of 3 conductor 8 gauge cord that was on sale at Home Depot and put various ends on as needed. That cord is an inch in diameter and seems like overkill when compared to the 1/2 inch diameter charging cord that comes with the car. (4 times the area.) The point is that as long as you choose an appropriate charging current you can successfully charge the car with an variety of extension cords.

Rheumboy | November 30, 2013

Go to EVSEadpters.com. They build a lot of e cords and different adapters for MS. Mine works great at the in law's 220. We'll priced and will overnite if needed.

robert | November 30, 2013

@DJay

No, the exact modulation of the gas pedal is impossible to achieve, and, worse, you concentrate so much on that that your attention isn't where it should be. Coasting in Neutral eliminates all that.

There are lots of threads about this.

shs | November 30, 2013

evseadapters.com has a series of adaptors, but not extension cords. If you can't get the right adaptor from Tesla, this is the place to go.

jbunn | November 30, 2013

One thing to consider when doing your first charge at a friends house that has an electric dryer outlet within reach...

Electric dryer plug standards changed from a non-grounded to a grounded plug about 10 years ago. So in the wild on 30 amp dryer circuit you'll see the older NEMA 10-30 (3 pin), or the newer 14-30 (4 pin).

I carry both adapters, since being caught off guard once.

DJay | November 30, 2013

@robert I'll give it a try with the shift lever.

Cindy I II III | November 30, 2013

I found short trips with long stops in the cold increase energy use like crazy, for it takes a lot to warm up the battery each time. Not sure if that contributed to your low mileage on the OP. The longer trips have much better numbers.

It might pay to have your destination send you a picture of their outlet - the adapter needed can be different from what you have.

David Trushin | November 30, 2013

It is no big deal to feather the pedal to achieve 0 power usage. You get the knack pretty quick . Plus if you need to perform an emergency maneuver you don't have to think about whether you are in neutral or drive and you don't have to take your hand off the wheel. Besides coasting is illegal in most places in this country (US).

robert | November 30, 2013

@David

You don't have to take your hand off the steering wheel. When I coast in Neutral, I rest middle finger on the "gear change" for fast action.
Funny with laws. What you say is forbidden in many States is officially recommended by the Swedish traffic and Police authorities and the State.

robert | November 30, 2013

@David

PS. And it IS a big deal. You can't, just up to a degreee, and you shouldn't be concentrating on the feathering, but the driving.

Pungoteague_Dave | November 30, 2013

Almost every state in the U.S. has no-coasting-on-downgrade laws. If you follow @robert's advice you are almost certainly violating the law. I don't know about other EU counties, but it is also illegal in Belgium and the UK.

http://skeptics.stackexchange.com/questions/14159/is-it-illegal-in-any-u...

In California the fine for coasting is $200 for first offense, $1,000 for second offense.

Some reasons that I have seen for anti-coasting laws include ability to react quickly and control the vehicle, for example if there is a sudden cross traffic or animal on road event, or a vehicle rapidly approaching from behind. Full control all the time is a reasonable reason, as power may be required in an evasive maneuver situation. In an ICE a key reason to not coast on a downhill is potential brake heating and resulting fade as well as lost engine braking. In theory this could apply to a coasting Model S, although is a reach. There are circumstances where coasting could catch you out in an emergency without time to think how to recover. Just because it hasn't happened to you doesn't mean it won't. It is a fact that you have more control over a vehicle that is in gear, whatever the road conditions.

The British driver instruction manual has an entire chapter on how to overcome what they call the bad habit of coasting. Here is the chapter intro:

"What is coasting?

We are frequently asked what is coasting by drivers or learner drivers. The fact is, many drivers don't even know that they are coasting. It is also a habit that learner drivers acquire on a regular basis and one that needs remedy.

Excessive coasting can potentially fail a driving test as it can be dangerous.

This article will describe what coasting is when driving, when stopping and the impact it has on the driving test.

The correct procedure to prevent coasting is explained amongst other frequently asked questions."

Coast at your own peril. ;-)

AmpedRealtor | December 1, 2013

Using single pedal driving in the Model S, holding the pedal so that there is zero energy usage and zero regen is tantamount to coasting. I drive my Model S this way quite frequently in order to reduce energy usage and maximize range. So am I breaking the law for simply driving my Model S in a normal fashion?

Pungoteague_Dave | December 1, 2013

AR, your method doesn't take the car out of gear, which is the coasting operation that is illegal. Your method is fine and is what I do. Beyond that form of coasting, there can be no technical benefit except in some owners' fantasies.

Brian H | December 1, 2013

PD;
++11

jjaeger | December 1, 2013

@PD - +1 and completely agree. Feathering the accelerator pedal is now 2nd nature, no concentration off the road ahead is required. By far the safer (and legal) of the two techniques.

robert | December 1, 2013

Those coasting laws may make sense for a manual ICE, since there is quite a lot that has to take place to put the car in gear. And I see the reason for only having one law.

But, as said, getting a driver's license in my country means that you have to be ripe and knowledgeable enough to drive a car, starting with age 18 (not 16 or, heaven forbid, 14) and passing several quite tricky tests. You cannot make laws for everyone to protect against idiots, for instance, coasting down a steep mountain, soon without brakes.

Therefore, since coasting has been proved to save a lot of energy (in whatever form), and assuming that people who drive a car also have the brains to do so, coasting is actively furthered in my country, by the official authorities. To each his own.

Pungoteague_Dave | December 1, 2013

It turns out that coasting is suicidal:

http://news.discovery.com/tech/euthanasia-sucicide-rollercoaster-ride-11...

Just say no.

jkn | December 1, 2013

@Pungoteague_Dave

There is no way to take MS out of gear! This 'neutral gear' switch Robert is using only disconnects accelerator pedal. So exactly what is illegal? (Clutch belongs to museum, not to modern car.)

Pungoteague_Dave | December 1, 2013

Jkn,

You are incorrect. The car does have gears and contains transmission fluid. Using shift by wire, the car responds to shifter stalk inputs and mechanically shifts the gearbox into three separate modes: forward, reverse, or neutral (park being a fourth choice on the stalk, which mechanically shifts to neutral and engages the separate rear brake parking calipers to the rear brake disks).

When the car is shifted into neutral for the purpose of coasting, there is no remaining connection between the motor and half shafts that drive the wheels. This is why @robert and his ilk can claim some savings and efficiency benefits. The claim rests on the theory that true unconnected coasting does not suffer the 20-30% efficiency loss that occurs with regen. I believe the same benefits exist by balancing the throttle at the point between acceleration and deceleration, effectively the same as coasting. This is easy to achieve for most, but @robert appears to find it difficult and distracting, perhaps a symptom of advancing age. I cannot prove my theory on this, and neither can @robert, but there is no engineering theory to support his method, only increased risk.

RonaldA | December 1, 2013

Accelerate in a range no higher than 20-40 kw. Drive between 0-20 kw. Use cruise. Avoid mechanical brakes. You will quickly drop below 300 wh/mile but one fast accel or quick move can set you back. Remember average wh/mile is what counts

RonaldA | December 1, 2013

Coasting out of gear disengages regen braking and loses energy to friction and wind resistance while adding no energy to the battery. In steep hills you can actually regen energy while maintaining velocity. Let up more on the peddle and slow down,press harder and speed up. Always try to accelerate going downhill or flat. Consider drafting if you can be safe about it.

jkn | December 2, 2013

Pungoteague_Dave,

MS has differential with some oil in it. I'm not certain, but I guess that there is not any gear between motor and differential. Small gear in motor could directly connect to differential. Sportster had two gears, but those broke down too often so they were removed.

MS certainly does not have mechanical gear sifting as you write: "mechanically shifts the gearbox into three separate modes: forward, reverse, or neutral". I don't have MS, but I understand how inverter and induction motor works (I mean it. If I used long enough time, I could build inverter my self.) It would be idiotic to implement reverse gear with mechanics. It can be done by changing timing of power transistors. If something can be done with software only, Tesla has done so.

I have an old induction motor, larger, heavier and less powerful than Teslas motor, but same principle. Without electricity it rotates completely freely. Only friction from bearings will slowly stop it. Again it would be idiotic to implement mechanical neutral gear. I completely trust that Telsa engineers know what they are doing.

You claim that it is easy enough to balance the throttle at the point between acceleration and deceleration. Robert claims that it is not. I don't know who is right. Robert claims much better mileage than you. So it seems that Robert is right. Perhaps you can almost find that balance point, but not exactly. At very low power levels efficiency is low. Don't waste time by giving single number efficiencies. Efficiency map from Telsa would be nice. Look http://www.acpropulsion.com/datasheet/ac150gen2.pdf If power drops below 10% of max power, efficiency drops rapidly. Motor & inverter are not optimized to used as a generator, so generation efficiency will be lower.

robert | December 2, 2013

PD

I am right and you are wrong (nice beginning, eh?).

However, this may be mostly theoretical. In my way, the meter doesn't move at all - it is completely horizontal.
Your way, you cannot, repeat CANNOT, keep the meter exactly horizontal. Even a small variation will waste energy, because what you use going up you don't get back ENTIRELY going down (regen).

Now this may for practical (see, I know that word, too) purposes be negligible, but, in order to keep the meter almost horizontal, you MUST spend a good part of your attention there. The lesser variation you allow, the more attention. If you don't, the difference between your lowest and highest will be larger. Thus in theory I am indeed right, but it may be unimportant.

You want to do that - fine with me.
I feel that coasting in Neutral, my right hand on "ten past", middle finger on stick, foot hovering above brake makes me ready for whatever, needs no concentration at all - that should go to the road - and I consistently drive under 260 Wh/mile, with studded Winter tyres, in freezing temps and lights on, not upsetting traffic.

To each his own. Why you have to mix in personal traits, like advancing age I find just abusive. Maybe advancing age gives me enough experience in the thought proc... no, I won't go there.

robert | December 2, 2013

@jkn

The different mileages that PD and I have aren't proof of anything. However, as long as PD does his "coasting" manually and I by changing stick, I'll bet anyone 1'000 Dollars to a sausage that I will have a better mileage than he, if we drive the same car the same distance under identical conditions. That's a given.

But completely unimportant.

gibbs | December 2, 2013

@robert, I think I want to grow up to be you. I drove around, and couldn't get a decent m/kWh...so I chickened out. I took the ICE. *bleh*

But all of this gets me thinking (putting on my software developer hat)...what if we could pull in topographic data, traffic light data, and build an algorithm off of robert's style of driving, and build a "hypermile cruise control". It looks like we have all of the data that we'd need to replicate his style of driving.

I really could use it now. After a weekend with an SUV, I came back to my Tesla, and now I'm getting whole 2.5m/kWh. :/

David Trushin | December 2, 2013

Build a hypermiling cruise control like that and what you would wind up with is the cruise control we already have. Do you really want the car to put itself in neutral independent of the person driving the car?

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