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Consumer Report on Winter Range Reduction

This is a much more balance and unbiased review of the Model S winter performance.

http://news.consumerreports.org/cars/2013/02/tesla-model-s-winter-chills...

Nelson

This should also be worst case, or close, given the long cold soaks.

Honest review from another reporter who would not plug in. I give the reviewer credit for understanding the energy display. Kudos to Tesla Motors for the extra range beyond zero. The Model S and its engineering are the true success story.

It's totally fair to not plug in and see what happens. It's an important measure of the car's performance becusse let's face it, sometimes you just can't. However you've got to be upfront that that's what you are writing about and you know the risks.

Also, I don't think he did a max range charge since he indicated only 240 mile range after charging With the full max range charge, it should add another 25 rate miles. This is an important point that probably needs to be highlighted in his report.

^Agree with the point here. Overall, the CR tester was knowledgeable about the car and this seems like a fair real-world cold weather test report. I bought the 85 kW battery with suspicion I would lose maybe 25% of rating in adverse weather. I guess my presumption was pretty close to what CR found in these conditions.

What was the point of this experiment? To show that you could run out of charge? Do you get in your Chevy and see if your quarter tank will go exactly the miles the readout tells you it will? Unless its an emergency, most dont do this type of thing. The typical thing would be to fill up or add enough gas to safely get you where you need to plus a little bit to get you to the nearest gas station. He said he wanted to demonstrate what a real owner would by not plugging in at night, but he failed to realize a vast majority would plug in at night or read that 188 miles means stay well within this limit and charge up when you get home.

I'm glad he demonstrated the estimated range was accurate enough for him, but he didn't explain how it's not the same as a gas car. You will have different habits. Explain what benefits using electricity to run the car, but also noting the trade offs. This is the real story, but yet again, another example of weak journalism. Broder already did something like this, but more alarmingly, most positive reviews are just as lacking. What would give people a reason to read, and a reason to tell their friends to read this publication, would be to assess objectively a tesla bev compared to a gas equivalent under the same conditions. Have a personality while doing it and represent a consumer who has no f-ing idea what an EV is or why they should care to bother being interested in it. That would get readers, that would really have power to decide whether Evs are going to live or die and attract respectable attention.

"Do you get in your Chevy and see if your quarter tank will go exactly the miles the readout tells you it will?"

If your a tester you do. That's their job, to run those sorts of tests. It's important for people to know how accurate the projected range is for when they are in an emergency situation.

I do think the standard versus range charge wasn't made clear in the article, though.

At least CR was aware of what they were doing and wrote an honest, objective article unlike the slam piece by the NYT.

The fact that the range indicated 55 miles and the Model S traveled 55 miles is perfect engineering. CU did their job in making sure that the stated range is accurate. (If I remember correctly, previous versions of software did allow for a average range to be displayed on the driver display.)

It would be fantastic if range was calculated through Google Maps Navigation. Temperature, weather, grade and descent could be combined with the habits of the driver to predict a more accurate answer. Add in the search for SuperChargers or charge stations for accurate trip planning. IMHO, the future is bright with advanced web data and computing power that can not only drive a car in the distant future, but give us the status of how best to charge up in the near future.

As a subscriber to CR, I have to say that this kind of test is exactly the kind of thing CR does. They test the cars (ICE or EV) at their limits. They did it to the Leaf, they're doing it to the Mitsubishi, and they do it to the MS. They are very thorough and take a lot time to develop their testing methodology. While they try to mimic real life situations, for the cars they often take them to their limits. As Tesla advocates we have to accept that sometime our favorite automaker and car will fall short in some tests.

Yes, driving an EV is different from an ICE, because the infrastructure is not there, and so your driving habits will have to change as well. However, until CR has released their full assessment (which I expect will be glowing overall), I would not be too hasty to describe their testing as pointless.

You should check out the links in one of the comments:

http://news.consumerreports.org/cars/2013/02/what-we-do-for-ratings-adve...

Even ICE car will have trouble starting in extreme cold weather.

"But when we decided to venture home, the weather had become very hostile with high winds and blistering cold temperatures. The temperature readout in our Subaru BRZ indicated -17° F that morning. I knew it was cold when I pushed the clutch in and it didn't immediately retract. Worse, we had parked our Ford F-450 diesel pickup and equipment trailer out in an open parking lot at a higher elevation, where the temperature fell to -22° F.

Not surprisingly, the truck wouldn't start—the diesel-fuel lines were frozen. Now what? Our plan was to fire up a generator to plug into the engine-block heater on the truck, hoping to thaw it out. More bad news: The generator wouldn't start and the portable backup generator we had was virtually frozen. No matter, we soon realized our pickup wasn't equipped with an engine-block heater, so nothing gained or loss here."

Nelson

I just had my first real world range test today (had the car since Tuesday). I have a 60 kWh, which I upgraded to based on my semi-frequent round trips of 160-170 miles to our corporate headquarters. I have not yet gotten special charging options at the corporate offices, but there are 110/15 outlets that I scouted out in the past few weeks, so I figured they were there to give me a bit of buffer, and keep the battery conditioned even in winter.

Anyhow, I like anyone else here, took it easy on the way down, to make sure I'd have range to get back. I got there (80 miles one way) from a range charge that I thought was supposed to be rated at 208 miles, but there was only 197 on the screen when I woke up this morning - ack -10 miles to start!). I brought a long extension cord in case I couldn't find a plug within the short range of the actual cord. I figured I could dial down the current if I had to.

So with over 100 miles of range, I found a spot I could reach an outlet in the parking garage, and felt I won a victory! Anyhow, after plugging in, seeing the car make its handshake, and start the green blinking, I went off to my meetings (around 5 hours, anticipated around 15 miles of extra range from charging at 110/12). I even checked my smartphone app to make sure it was charging periodically, and confirmed that it was in fact still plugged in, and the screen still said 110/12 charging at 3 miles/hour. Anyhow, I was alarmed when I got back to the car at the end of the day, and the status light was no longer blinking. The display still said 110/12, 3 miles/hour charge rate, but my reported range was only 108 miles! WTF I was plugged in, and my app said it was charging. I am not sure if maybe the outlet was not live, I figured I still had enough range to get home safely, but I was not sure if maybe it was uphill home or not, so naturally I was nervous (range anxiety!). Has anyone else experienced this? Has anyone else had the blinking green switch to off?

(update!) My wife said the car did this tonight when she got home. The light was off, she walked up (and her fob lead the car to greet her with extended handles), and the blinking green light turned back on. I'm guessing this means that it is just not blinking because the fob is out of range, and it goes into sleep mode?).

This is especially concerning to me at this point because having only 4 days of experience with the car, all of which I knew I had plenty of range, and therefore not particularly range concerned, I had been accelerating strongly and such (normal behavior with a car this awesome), so I had not seen my projected range get up to the rated range. Thus the anxiety.

Anyhow, I was able to by using surface roads get significantly better than rated range, so I ended up getting home with 26 rated miles left, so I have gained confidence in the range. It was ~30 degrees F today, so chilly, but not overly cold.

So yes, people will need to know if the car will really go as far as rated. This information is critical to the decision to buy the car. I bought it expecting 208 miles of range based on the EPA rating, giving me plenty to go to corporate and back. I drove cautiously today, 160 miles round trip on a full range charge, and got my 160 miles with only 26 rated miles to go, so 186 miles. That's not too bad, but a bit uncomfortable. If I took highways the whole way, it would have been bad as I seem to get much worse range that way.

I'm happy, but I can see how you could get into trouble, and there's no certainty that I won't at some point...

@Leofingal - I'm not confident that the mobile app is accurately representing (yet) what the car is doing. In particular I think the app can think the car is doing something (charging) when actually it isn't.

I've got into the habit of killing the app in iOS and then restating it each time to guarantee that it gets an up-to-date reading from the car, rather than trust that it will update. Someone posted a problem with the app reporting climate control was on, when in fact it wasn't.

Not bad Leofingal. You started off with 197 and got about 186 miles out of it in cold weather. Looks like you only lost 11 miles. That is the perfect info I need since I am doing a very similar test Saturday except I have a 240 volt 40 amp charging option in two places during the trip if I need it.

I am charging my car to a standard charge tonight. Then when I get up a few hours before I leave I will set it to range charge. That will heat up the battery and top it off so I am not missing any mileage.

nickjhowe also makes a good point. I too have been killing the Android app and restarting. Seems to be more accurate that way..... at least I feel more comfortable that way.

nickniketown you don't even own a car. How can you feel any pain?

@Leofingal | FEBRUARY 15, 2013: I'm guessing this means that it is just not blinking because the fob is out of range, and it goes into sleep mode?).

If the car locks, the charging port light goes out. You probably have walk away locking turned on.

I took a drive into New York City from the Hamptons a few weeks ago, a trip that is almost exactly 100 miles...In weather that was cold and windy in the mid-20's, I used 130 miles of Rated Range to go 100 miles (almost identical results there and back, and I had a passenger on the way back).

Earlier this week I replicated that same trip, although the weather was in the mid 40's...My actual mileage was pretty much exactly 1:1 with my Rated Range, which made me very happy. I assumed that Rated Range was going to be over-estimated, but in certain conditions, it ends up being a very realistic real-world estimate.

FYI, for 75% of the drive both times, I had the car on cruise control at 65 mph, had the heating set between 70-72, and used the seat warmer for part of the time, and had the radio on the whole time (And, did not have the car operating in Range Mode).

The difference in mileage on the colder drive appears to be pretty consistent with then 25% cold weather range loss figures quoted, and I'm OK with that. And I'm glad that I now have an idea of what my car can do in ideal conditions, and less than ideal conditions..

Fascinatin'! Someone suggested a 1-mi. range reduction for every degree below 70F. Thought that was a doubtful formula; your loss experience seems much more "constrained" to the freezing zone.

If a high amount of battery conditioning must take place upon plug in (heating the pack in cold weather) does a 110V 15A plug supply enough surplus to actually "add miles" in very cold / hot conditions?

What is the battery conditioning current draw? Is it possible that in extreme cold with a cold pack that 110V might only be a break even at best due to pack heating draw? Thoughts?

@TheAustin

If you are trying to stretch the range, turn off the cabin heater and run heated seats only. You will be much warmer, with considerably less energy use. Conductive vs. convective heat transfer (for the nerds out there :)

kalik;
someone cited 100W vs 3kW.

kalikgod,

Using the seat heater is fine for the body but these cars have cold footwells by design and that strategy only makes the feet that much colder...

@Leofingal - I have also come back to my car and had the green light in an off status. The amount of charge / range also fluctuates. What I believe the car is doing is it charges up fully, then quits. After the cold (about 60 F in my garage) and passage of time drains some power, then below a certain point the charging kicks in again and it goes back to topping it off. My 85 kw gets down from full charge of 244 to about 235 when I have observed this to occur. Using my iPhone app, I can get it start recharging again manually by briefly switching to 'max range' and then back again to 'standard', which seems to get it to go ahead and charge up to 244, regardless of whether it's gotten down to 235 or not.

My Green Light goes off when I lock the car.

The CR effort was spot on but for one point. Tesla documents range loss with time and lower temperatures so any evaluation of trip requirements mandates range reduction for not plugging in over night in a cold environment. Had this been added to the initial trip requirements I think the piece would have been a perfect test and reorientation of the car.

representation.....


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