evnow
Well-known member
TimeHorse said:
The links to original articles are in this thread - you would have to dig.
The 6,7 above are at constant speeds ("cruise").
Preliminary RANGE results
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The links to original articles are in this thread - you would have to dig.
The 6,7 above are at constant speeds ("cruise").
I dont know if its relevant but I saw a recent video of a test drive in Japan and in the video we get to see every now and then the speed and estimated range and from that test drive on an circuit (similar to highway) it appears that the 'estimated' range does not go down significantly as long as the car goes to around 100 km/h - 110 km/h but that beyond 110km/h (about 68mi/h) the faster you go the more the estimated range figure really drops.
IceRaven said:
Definitely relevant. I think we already decided that there was a highway range "sweet spot" between 60 and 70mph, but this just goes towards reconfirming it.
DeaneG
Well-known member
mwalsh said:
It depends so much on exactly what the guy's foot was doing when the video passed over the estimated range display.
EVDRIVER
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mwalsh said:
Its usually 55 as drag goes up much faster past that point. Most of the energy used it just pushing air out of the way. The early thinks were limited to 58 mph and they were reluctant to go higher but they did on new models. I used to have an original copy of the aero track tests and efficiency for the Think at every speed. The car was rated at 50-60 mile range but at certain speeds that range could be more than tripled of course. There was also a switch on the dash to lower the charger draw on la ower amp circuit and a switch to turn off regen so you could clean the rust off the brake rotors. If you turned off the regen on the highway you got a few more MPH on the top end but stopping was scary!!!
tomsax
Well-known member
I just finished reading this thread, lots of good comments. With the discussion of how range can vary with driving conditions, etc., I thought the group might be interested in seeing a chart of real-world EV driving data. The chart below shows range versus average speed for eight months of Tesla Roadster driving in the Seattle area. Although the car is a Tesla Roadster, I try to drive efficiently most of the time. I'm sure the range values would be lower for many other Roadster drivers.
The data is for every drive segment from Oct 5, 2009 through July 4, 2010 that used at least 10% of the battery pack, minus a few extreme outliers (like 6 miles of autocross-style track laps and 38 miles dropping 2600 feet of elevation). The range is computed by extrapolation, meaning if I drove 20 miles and used 10% of the battery pack, I count that as a range of 200 miles. The highest range shown (256 miles) was a drive from Seattle to Portland, staying near or under 55 mph, and one of the 64 mph points was a segment of the trip back. The worst range shown, 155 miles at 39.4 mph, was December 9, 2009, a cold day with temperatures in the 20's which included some 70+ mph uphill freeway driving (it also happened to be the day my wife and I got to drive the Leaf mule in the Qwest Convention Center parking garage).
I think it's interesting how much range varies and how nearly all of the points are below the 244-mile range that Tesla quotes most prominently. If you scale the data down to the Leaf's range (for example by scaling the 250 line down to 100 miles, which would put the bottom bounding line around 150 at 60 miles and the median of 192 at 77 miles), it might be some loose approximation to the performance my driving habits would yield on the Leaf. That may be wildly inaccurate, but it's something to consider.
The data is for every drive segment from Oct 5, 2009 through July 4, 2010 that used at least 10% of the battery pack, minus a few extreme outliers (like 6 miles of autocross-style track laps and 38 miles dropping 2600 feet of elevation). The range is computed by extrapolation, meaning if I drove 20 miles and used 10% of the battery pack, I count that as a range of 200 miles. The highest range shown (256 miles) was a drive from Seattle to Portland, staying near or under 55 mph, and one of the 64 mph points was a segment of the trip back. The worst range shown, 155 miles at 39.4 mph, was December 9, 2009, a cold day with temperatures in the 20's which included some 70+ mph uphill freeway driving (it also happened to be the day my wife and I got to drive the Leaf mule in the Qwest Convention Center parking garage).
I think it's interesting how much range varies and how nearly all of the points are below the 244-mile range that Tesla quotes most prominently. If you scale the data down to the Leaf's range (for example by scaling the 250 line down to 100 miles, which would put the bottom bounding line around 150 at 60 miles and the median of 192 at 77 miles), it might be some loose approximation to the performance my driving habits would yield on the Leaf. That may be wildly inaccurate, but it's something to consider.
garygid
Well-known member
Tom,
Thanks for the great data.
It illustrates how much driving conditions can affect the range.
It would seem that any simple range vs. speed curve is likely to be totally misleading.
Thanks for the great data.
It illustrates how much driving conditions can affect the range.
It would seem that any simple range vs. speed curve is likely to be totally misleading.
Stoaty
Well-known member
Tom,
Interesting data. Doesn't look anything like the Tesla curve of range vs speed you posted on another thread. Guess the real world throws in a lot of "kinks" not accounted for in that nice curve
Interesting data. Doesn't look anything like the Tesla curve of range vs speed you posted on another thread. Guess the real world throws in a lot of "kinks" not accounted for in that nice curve
evnow
Well-known member
tomsax said:
Is the speed the avg speed ?
tomsax
Well-known member
That's right. I believe the Tesla chart is very accurate for what it is. If I drive at a steady, constant speed on level freeway, I have faithfully reproduced the values from Tesla's chart in the cases I've measured. But my graph isn't for steady speeds, it's for real world, generally very variable driving, start and stop on surface streets, heavy or light freeway traffic, a wide spectrum of real driving.Stoaty said:Interesting data. Doesn't look anything like the Tesla curve of range vs speed you posted on another thread. Guess the real world throws in a lot of "kinks" not accounted for in that nice curve
I think the big takeaway from my chart is that average speed tells you almost nothing about the drive. As the chart shows, I can have multiple drives that average 40 mph, but the range/energy use varies by more than 50%. I'm sure I could get a factor of two in there if I could actually go a steady 40 mph long enough to use 10% of the battery pack. So, I recommend high skepticism of any range spec that gives only the average speed.
garygid
Well-known member
Again, very helpful real-use insights.
Thanks Tom!
Thanks Tom!
I'm sure you know this since you actually own a Tesla, but you know that the range on a normal change is well below 244 miles unless you charge and drive the car in "range" mode to protect the battery?tomsax said:
As such, any reference to 244-mile range is comparing apples to oranges. It's too bad that Tesla doesn't have a published range in normal charge/drive mode as that should be the number used for comparison.
I suspect that the "real life" range when not using range is actually slightly below 200 miles as I believe that range mode simply lets you charge the battery an extra 10% and discharge the battery an extra 10% so normally you use 80% of the full capacity of the battery.
If you use a bit less than 200 miles as the actual range of the car, it does appear that all your points seem to average around that number quite nicely.
LEAFer
Well-known member
drees, correct on all points
Except maybe on the last one ... that's because (to be consistent) Tom extrapolated a 10% discharge (driving) to 100%. The fact that it "seems" to average around the 200 number is more due to the fact that his data points are real-world based, not a reflection of the difference between Standard and Range Modes. And, yes, the Tesla is VERY protective of its battery, so the default mode is "dummy" mode (Standard Mode) where you don't worry about anything, and it will only use the middle 80% of its full capacity (and so has a 10% reserve built-in at the bottom end in case you run low). So 80%*244 = 195 miles. To do a Range Mode charge, you have to acknowledge some warning messages about battery life to override "dummy" mode, and that's probably something Tesla drivers need to do rarely.
Except maybe on the last one ... that's because (to be consistent) Tom extrapolated a 10% discharge (driving) to 100%. The fact that it "seems" to average around the 200 number is more due to the fact that his data points are real-world based, not a reflection of the difference between Standard and Range Modes. And, yes, the Tesla is VERY protective of its battery, so the default mode is "dummy" mode (Standard Mode) where you don't worry about anything, and it will only use the middle 80% of its full capacity (and so has a 10% reserve built-in at the bottom end in case you run low). So 80%*244 = 195 miles. To do a Range Mode charge, you have to acknowledge some warning messages about battery life to override "dummy" mode, and that's probably something Tesla drivers need to do rarely.
tomsax
Well-known member
I'd say the real range of the car is 244 miles. Actually driving that far on a single charge is not a good idea, in much the same way that driving a gas burner until the tank is empty is not a good idea. But, if you really want to drive the full range of the car every day, there's nothing stopping you from doing it.drees said:
I really hope people aren't buying Roadsters expecting to use that 244-mile range every day. They'll be sadly disappointed. Much like the one EV1 driver I've heard of that didn't like the car because he bought an EV with a 75-mile range (one of the original lead-acid models) for a daily commute of 74 miles. (I believe he was misled by the sales people into thinking the car would work for him, a rare exception to the rule of competent, passionate Saturn sales people and enthusiastic, happy EV1 drivers.) The reason I'm here posting to this thread is to help ensure this doesn't happen to any Leaf customers that are paying attention.
Since it's better for the lifetime of the battery pack to stay out of the top and bottom 10%, Tesla makes it possible, and in fact encourages us, to do all of our normal, daily driving in the middle 80% of the battery pack so that we protect the health of the battery pack and hopefully extend its useful life well beyond the (admittedly anemic) warranty period.
If you want to beat up Tesla for fudging the range numbers, I think their biggest offense is saying that it has a range of 244 miles and can be fully charged in as little as 3.5 hours. The 3.5 hour number is for a full standard mode charge, a full range mode charge takes more like 5 hours.
But this has got nothing to do with my graph. I chose to extrapolate the energy use of the many drive segments up to the full range mode battery pack. I could just have easily scaled it up to the equivalent 195-mile standard mode range, but that would only change the scale on the graph and my final statement would have noted how "nearly all of the points are below the 195-mile standard mode range."
The real question before us is what Nissan means by their range numbers. Are those numbers for staying within the bounds of the "nice" battery usage, or is it more like Tesla's range-mode numbers that imply a shorter battery life if used daily? Even more to the point, what is Nissan's warranty on the battery pack, and can we drive the full range of the battery that's implied by their range numbers every day and not shorten the battery life or void the battery warranty.
FWIW, for my Roadster, the standard mode charge usually shows 192 or 193 miles, meaning I can drive that far on flat at 55, with a 10% reserve that I can access at any time by switching to range mode. The 244-mile range is only interesting for longer trips where I'm going to be willing to do a little planning, make allowances for not getting that range unless I'm driving on level freeway at a steady 55 mph, and I still reserve a buffer at the bottom as a safety margin. I know I can always drive 150 miles in standard mode under pretty much any normal driving conditions without even looking at the charge meter, beyond that I need to think about what I'm doing.
What's the "don't need to think about it" number for the Leaf? What's the best case freeway number for planning a long trip, the point from which I moderate my driving, subtract out a safety margin, and plan for charging stops? The answers to both of those question are not absolute and depend on the driver, the roads, and the climate. So far, Nissan hasn't given us enough consistent information that I can determine that number for me. With the Roadster's ridiculous range, so far above 99.5% of everyone's daily driving needs, the details didn't matter that much for daily driving. It's a far more interesting issue for the Leaf.
DaveinOlyWA
Well-known member
thanks for the data Tom. i am impressed that your best #'s is a trip i would make but going from Olympia to Salem. i do it in my Prius frequently. try to stay under 65 mph (in the Leaf i will not do more than 60 mph) and get the mid 50's.
planet4ever
Well-known member
Thank you for putting it so well, Tom. I believe we were at first given the impression that the total Leaf battery capacity was 24kWh. Then we were told usable range was about 23kWh, which didn't make sense to people who were familiar with lithium batteries. More recently I have been reading that the usable range is 23 to 24kWh, and assertions that the total size is something larger than that, but Nissan doesn't seem to be giving any hints as to how much larger, if any. So I agree, your questions are exactly on point.tomsax said:
evnow
Well-known member
evnow said:
Some differences in what Leaf site says now. They have left out the 6 mph crawl and small changes to the avg speeds of others.
LEAFfan
Well-known member
I'll be using Scenario 10, but at 65 instead of 60 and I'll still get over 100 miles by using ECO mode. I remember some much earlier posts about how on the hwy at 60 or 65 that we'd only achieve 70-80 miles. I knew that was poppycock.
I remember some much earlier posts about how on the hwy at 60 or 65 that we'd only achieve 70-80 miles. I knew that was poppycock.
