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Conditions for the stated range

Conditions for the stated range

I don't own and EV right now but I will by the end of next year (I hope), and searching this forum is troublesome at best ...

When they state the range of an EV, say the 215 miles for the M ☰ , what conditions are they assuming exist in order to get that range? Are they looking at 65 F, sunny, cruising at 60mph with cruise control on and no radio? Or are they assuming the worst and it's 85 F, raining, and at night so you have the AC, the headlights, and the wipers all on, as well as cranking the radio. I know there are a lot of factors but I'm trying to get an idea of the assumptions that are made in order to determine real world expectations based on how I drive.

Knowing what the assumed conditions are, can you then get "extra" miles by turning off the radio, not running the AC, or are those negligible?

thanks

Bighorn | 2016年5月10日

It's the EPA 5 cycle test

PhillyGal | 2016年5月10日

Radio is negligible, heat is not.
The biggest factor in range is cold weather in my experience. Going uphill through mountains hurts too.

Driving fast takes more range too so if you need to stretch range, you slow down and turn off the heat. (Use seat heaters instead if needed.)

moorelin | 2016年5月10日

Close to the bottom of the main Model S intro page, there is a calculator that shows the effects of outside temp, speed, heat/AC, and wheel size. Doesn't go to high speeds or very cold temps, but gives the basic picture.

dsvick | 2016年5月10日

@Bighorn
Thanks, I didn't know that. So it looks like they try to test it like a typical person would drive. And, literally in this case, my mileage may vary.

@PG
So no driving fast in the winter in the snow? My wife will be glad to hear that :)

PhillyGal | 2016年5月10日

@dsvick - Not on long trips anyway ;)

Though I did mistakenly accelerate down an icy hill in my S85 (rear wheel drive) and have to say the car snapped back into place before I even realized I slipped. It was a marvel.

Red Sage ca us | 2016年5月10日

Elon Musk has specifically stated that he wants Tesla Motors' cars to have a 'Real World' range of 'at least 200 miles'. He said that would mean just 'driving normally'. So, not hypermiling or in perfect weather conditions on flat ground.

From all the multitude of conversations that have been held in these forums about 'Range Anxiety' and its counterpart 'Range Awareness', it seems that those most worried about having 'Enough Range' tend to be those who want to maintain the bad habits they gleaned from driving ICE vehicles their whole adult lives.

That is, they don't want to have to plan trips or pay attention to how far one place is from the next. They want to glance at an indicator that says they have 'a quarter tank remaining' get off at the next exit to 'fill up' in a mythical 'five minutes' then continue on their way. They do not want to be 'bothered' to think about anything at all.

I find that strange, because even driving an ICE vehicle, I have always planned my stops when driving cross country. I would drive to the very limit of range most times before stopping (orange FUEL indicator light glowing brightly). And I would always allow for at least one stop more than was absolutely necessary to cover the distance. Typically, the result is that due to the biological needs of other passengers, we end up stopping at least twice more than absolutely necessary.

Those who worry, but don't want to think, seem to really want saturation of Superchargers that is greater than necessary. In urban areas, they want them 'on every corner'. On the highway, they want to see them 'at every exit'. Both, they say, would be 'just like gas stations'.

Strange thing is, I have not observed that as being true. In my travels, all of the 'Last Chance GAS' stations are long gone. Abandoned, closed, shut down -- because cars tend to have better fuel economy now -- much greater range than they did in the 60s and 70s. So no one finds themselves stopping in the desolate wasteland of complete nothingness between population centers anymore. Gas stations are not at every exit, they are where they need to be for modern cars, and the gas guzzlers of old can no longer span the distances between them on the highway. Of the nine gas stations that were within 1-1/2 miles of my house, only three are left -- and none of those are open all night.

Being able to fill up at home in your own garage changes things tremendously. You won't need to have a Supercharger within fifty miles of home typically. Urban Superchargers will exist for the use of those who are passing through on their travels, or someone in an apartment or condominium who does not have an assigned parking space or access to home charging.

It will be some time before those who refuse to relinquish bad habits will be satisfied, if ever. They'll want the stated range to be equivalent to starting at 90% full, arriving 350 miles later, and still having a 20% charge remaining. As far as Elon and JB are concerned, if you aren't going to drive more than 350 miles anyway, you don't need to have 500 miles of range. 400 should be 'enough'.

Hi_Tech | 2016年5月10日

I find that those that ask the question are the ones that are willing to do a bit of early planning (hence the need to ask about it ahead of time). With this mindset, it's fairly easy to understand what Tesla has built out and can therefore easily handle the longer term ownership.

Also, note that the Navigation feature in the Tesla accounts for the amount of charge in your vehicle and which SuperChargers to stop at for the longer commutes. It really does make things a bit easier, even for people like myself (and apparently Red Sage) who like/prefer to plan ahead of any trip. :-)

dsvick | 2016年5月10日

I don't really have any range anxiety. I drive maybe 60 miles a day on the average and will able to charge at home each night. Right now I've got a Corolla and, while I'm not rolling through stop signs or anything, I try to do what I can to increase my mileage as much as I can and have my average mileage almost that 35mpg highway estimate.

I mostly asked because I wondered if by paying attention and continuing my current habits I'd be able to do better than the estimated average. From reading the above comments it sounds like I will - which is cool.

Sigh .... It's going to be a really long year and a half....

jordanrichard | 2016年5月10日

The same things that effect an ICE car, effect an EV. It is just not as noticeable in an ICE car because most ICE don't have a range, aka "Miles to Empty" readout always on display.

Badbot | 2016年5月10日

epa tests allow you to compare any car to another. So all tests are on a dynamiter. they have the computer simulate city and hi way driving. but the simulation is the same for all tests.
the real world has too many variables, hot, cold, nice, wet, snow, ice, gravle, asphalt, concrete, and verying degrees of any or all the above.

But, I think something slipped by most of us here. We know cold is very bad, and very hot is bad. But tesla has the battery cooling system, but wait there is more. that cooling system can be used to condition the battery(warm it when it is cold as well as cool it when hot. this can be done by the charger.
It is done while driving so in a few miles cold batteries get warm and the cold efficacy drop disappears or diminishes.
Before I get flamed, 90 below 0 will exceed the ability of the system to adjust to the BEST temp but it will get closer to best than without it.

tommyalexandersb | 2016年5月10日

Does accelerating quickly deplete the batter significantly faster?

Bighorn | 2016年5月10日

@tommy
There's seems to be minimal to no penalty for brisk vs slow and steady acceleration.

mntlvr23 | 2016年5月10日

@bighorn - I would think that always briskly accelerating (especially in city driving) would lead to considerably less range - as it uses the energy to quickly get up the speed, but then wastes much of that energy if you have to prematurely brake (even though some of the energy is regained through braking). Kind of the opposite of hyper-miling. Is that not true? Or are saying that there is no penalty of quick acceleration on long open roads where you will not be planning on using the brake versus accelerating slowly? Thanks.

Bighorn | 2016年5月10日

@mntlvr
The latter--using the brakes robs efficiency. How you get up to speed does not seem to matter. How you slow down does--coast and regenerate as much as possible when coming to a stop. Ideally, just use the brakes to remain stationary or killing the last couple MPHs. Some will intuitively disagree based on their knowledge of ICE efficiencies, but they're wrong.

mntlvr23 | 2016年5月10日

thanks, that makes sense.

topher | 2016年5月11日

There is no factor for acceleration in the equation for energy use in a car.

There *is* one for losses due to braking (so don't do that).
There *may* be an issue with the efficiency of batteries when drawn hard in rapid acceleration.

Thank you kindly.

steveg1701 | 2016年5月11日

@ed so the EPA tests don't take into account the drag coefficient? Doesn't that penalize the better designed cars?

Badbot | 2016年5月11日

YEP!
Remember It's a government facility, ;-(

Hmmm technically It might but at 0 MPH very little data of value, :-P the dyno sits in concrete.

Haggy | 2016年5月12日

Range anxiety is much more of an issue for people who don't own an EV than for people who do. It's a concern for people buying an EV, but most likely goes away once they have one. If you can charge at home and drive an average amount, you won't come close to running out of range on typical days if you charge each night. On long trips, the car will let you know which chargers are on your route, when you need to charge, and whether you have charged enough to be ready to leave. You might have some leeway. For example, if you know that the next stop will be for lunch, you might want to spend less time charging at the current stop since you will be in a restaurant and can afford to charge longer without slowing down your trip. When you don't have enough charge or are going out of range for a supercharger, the car will warn you that you need to change course. If you are heading toward a supercharger, but your projected range is too short, the car might tell you that in order to get there, you need to slow down to a certain speed.

Things got to the point that on my latest long trip that I had my choice of chargers and was able to skip ones that were suggested and go to ones that weren't. Unfortunately the current navigator isn't set to deal with that very well, so I had to change my destination to the supercharger itself in those cases, and then set the navigator back to my trip when I got there.

I don't know what battery sizes there will be, but I would have been able to make my most recent trip of about 850 miles even with the smallest size battery without much additional delay. I had one stop where I ate and got back to the car when it had 240 miles of range. With a 225 mile battery, charging only to 225 wouldn't have affected the rest of the trip at all. Adding the same number of miles of range at each subsequent stop would have taken the same amount of time and I had enough range left at each stop that I wouldn't have had a problem. The only question is whether it would have taken longer to charge a 225 range battery to 100% than it took me to charge my battery to about 93%. In my case, the charging hadn't slowed down too much by the time I left, and with a smaller battery it would have slowed down more sharply at 200 miles. But on the other hand, it would have charged for fewer miles overall. So that was one leg on a round trip that might have been delayed 15-20 minutes. If that happens once a year because you saved $10,000 on a battery upgrade, that might be something you could live with. With a larger battery, considering that I would have had meals and restroom stops anyway, the trip was actually faster than it would have been had I made the same stops and not charged, but had additional stops to buy gasoline.

jordanrichard | 2016年5月12日

To Haggy's remarks about skipping chargers. In March I drove to North Carolina from CT, with the last long road trip being in Feb of 2015. On that trip in Feb 2015, we had to stop at the charger in Hamilton NJ. This site is about 3 miles off the NJ turnpike. When I made this recent trip, I noticed that they added a 4 stall supercharger site at one of the rest areas on the NJ turnpike. Though I didn't need it, but I figured it was literally right off the highway and this would enable me to skip Hamilton, which would save me time.

As time goes by and the density increases, the ability to skip locations will become the norm.