Reliable EV Data for Comparison

TimeHorse said:

But enough of my crazy East-coast state. The point is, I drive an average of 51 mph to work. That's by no means my top speed. I hit speeds well in access of that (though never more than 14 over the limit -- did I mention the Class-6 Misdemeanor??) and a number of local roads. That's why US06 is such a good measure for me. It has acceleration, deceleration, reasonable maximum speeds and an average speed of about 48 mph, much closer to my 51.

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My question is - why is that avg speed non-negotiable ?

TimeHorse said:

Preaching to the choir, sir! That's why I want a power curve so we don't have to so much extrapolate as simply run the numbers.
<snip>
In my state of Virgina I'd never drive that fast even if I could since I don't want a permanent Class-6 Misdemeanor charge on my criminal record.
<snip>
But anyway, thanks for the numbers, sir, as those 3 data points are just what I need, in theory, to compute the power curve for the cars listed. Not the Nissan LEAF, alas, but if I can get it to work for the others, I know I'm on the right track!

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I'm here to help and am happy that the numbers are useful! I look forward to the rest of the Leaf data as well - curves, 'fuel economy' numbers, etc.

Are radar detectors still illegal in the Commonwealth?

[edit] If you haven't seen them already, the one-page summaries are linked from the first post in the thread. More detailed info on the US Electricar Prizm and Ford Ecostar can be found here. The Prizm and Ecostar results provide much more 'energy used VS. speed' data.[/edit]

Andy

Charts are updated to include the 2009 MiniE. Test report is here. Constant-speed range is now reported at 55 and 65 VS. the old 45mph and 60mph.

evnow said:

My question is - why is that avg speed non-negotiable ?

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Do you mean why I can't just take the calculation at an average speed? Well, for the most part an average speed is good, but technically, from my research, your main drag -- if you'll pardon the pun -- is air resistance which is proportional to the square of the speed of the car. That means that if it takes x watts to go 45 mph, it may take 2x watts to go 60 mph and then 4x watts to go 75 mph, as a rough calculation. Now that's the power you need to go that speed. To get the energy draw, you just multiply the power times the amount of time you're exerting that power to get the energy. Hence kWh: kilowatts times hours. For illustration purposes, if you spend 1 second at 45 mph and the next at 75 mph you've basically used 5x Joules of energy, but if you spent those 2 seconds at a constant speed of 60mph, your energy used is only 4x. That's why average speed isn't the whole story. That's why EPA LA4 is more complicated than just 19.6 mph: it's really the sum of the intervals from second 1 to 1370, over a minute of which is idle and another nearly 2 minutes are at highway speeds.

However, if the Power Curve of the Nissan Leaf is known or reasonably estimated, we could calculate the expected range of the LEAF under HWFET or EPA75 or US06 or under any other custom, well-defined regime. And with 3 points, e.g. 45 mph, LA4 and 60 mph, it should just be possible to tease out that quadratic power curve equation...

TimeHorse said:

evnow said:

My question is - why is that avg speed non-negotiable ?

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Do you mean why I can't just take the calculation at an average speed?

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No. Why do you have to drive at that high avg speed ?

evnow said:

TimeHorse said:

evnow said:

My question is - why is that avg speed non-negotiable ?

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Do you mean why I can't just take the calculation at an average speed?

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No. Why do you have to drive at that high avg speed ?

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Sorry, I'm still confused. I don't have to drive at an average speed. But if I drive at LA4 on the I495 Capitol Beltway I'm gonna get a ticket. Sure, I could spend nearly 2 hours in traffic to get to work each day just so my average speed remains around 19.6 mph, but who in their right mind would spend 3-4 hours getting to and from work when there's this lovely highway that we taxpayers paid for that will get me there in typically 45 minutes or better. After all, I have to go 33 miles to work, 33 miles home, estimate about a 67 mile round trip. Sure, I could do that at low speeds, but really, does that make sense?

But certainly I don't have to drive at that speed. I also don't have to go to work or pay my mortgage but if I don't do these things there are consequences. I'm just weighing my options and I feel I am better off going 51 mph on average to and from work, the great majority of which I spend on roads with speed limits of 55 mph.

Here's another look at range. This info is from the DOE and Southern California Edison's Pomona Loop city and highway on-road testing. They run the vehicles with different loads and with/without AC and lights. Testing included Nissan Altra and Honda EV+.

Here's the Pomona urban and highway loop maps and elevation data.





The Altra was a somewhat heavy station wagon - but look at how much better the lithium-powered car performs compared with its lead- and nickel-powered stablemates.

Note that some do BETTER on the "freeway" test.
Maybe that test had less stopping?

AndyH said:

The Altra was a somewhat heavy station wagon - but look at how much better the lithium-powered car performs compared with its lead- and nickel-powered stablemates.

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I thought Altra did worst - in the sense its UR4 dropped considerably compared to UR1.

More surprisingly UR4 is worse than FW4 for almost all cars.

AndyH said:

Here's another look at range. look at how much better the lithium-powered car performs compared with its lead- and nickel-powered stablemates.

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Looks like running AC an such has an equal impact as running with a fully loaded car, and then when you do both...wow. Shows just how much impact weight has on the efficiency of a car. Time to go for a run...I'll be right back.

AndyH said:

All righty then - let the fun begin. Folks are wondering about how far the Leaf will move on a charge.

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Andy, I don't need this to calculate range at a fixed velocity but the thing is to make the calculation more reasonable I was wondering if you could compile battery capacity into your charts. This would allow me to work in energies rather than inverse ranges which make more sense from a common sense point of view. I don't need those numbers to work, but it will definitely make things easier and we already know the Nissan LEAFs capacity so it's not like it's information we couldn't work with when doing our final numbers.

(Oh, and yes, Radar Detectors are still illegal here.)

TimeHorse said:

Andy, I don't need this to calculate range at a fixed velocity but the thing is to make the calculation more reasonable I was wondering if you could compile battery capacity into your charts. This would allow me to work in energies rather than inverse ranges which make more sense from a common sense point of view. I don't need those numbers to work, but it will definitely make things easier and we already know the Nissan LEAFs capacity so it's not like it's information we couldn't work with when doing our final numbers.

(Oh, and yes, Radar Detectors are still illegal here.)

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In the mountains we forget to count the days.

My intent was only to sift thru some of the reports and present some bite-sized views. I did list battery size and charging info in post 8. I highly recommend that you build your model with data from both the single-page summaries that I'm pulling info from, as well as one of the more thorough reports like this for the NiMH Ranger. The Southern California Edison reports list temps, energy used, times, etc. for on-road tests. The Idaho National Labs reports provide much more detail from dyno tests.

I'd post direct links, but I can only include two links per post. ;(

I hope that helps,
Andy

One thing I see missing in all your distance/mileage calculations and comparisons with other BEVs: You may have forgotten that unlike most of the the other BEVs, the LEAF has ECO mode which will give you an extra 10-15% distance.

Does ECO mode just limit speed and acceleration?

garygid said:

Does ECO mode just limit speed and acceleration?

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From what I've read lately, I believe ECO mode increases the regen braking which gives you that extended range. All you have to do is ease off the accelerator pedal slightly to get extra regen. So even at hwy speeds (65mph) you could easily extend your range by 10-15%. I have a ScangaugeII for my cng Honda Civic GX and I've learned that when I've reached the speed limit, no matter how fast or slow, I can ease off the pedal just a 'hair' and my MPG increases immensely (from low 30's to high 40's) and still maintain the same speed.

leaffan said:

One thing I see missing in all your distance/mileage calculations and comparisons with other BEVs: You may have forgotten that unlike most of the the other BEVs, the LEAF has ECO mode which will give you an extra 10-15% distance.

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I'm only reporting bits of info from standardized testing - just the facts - and not trying to further process or guess.

I agree that an ECO mode should make a difference - as would all the ECO variations that our right foot allows.

leaffan said:

From what I've read lately, I believe ECO mode increases the regen braking which gives you that extended range. All you have to do is ease off the accelerator pedal slightly to get extra regen. So even at hwy speeds (65mph) you could easily extend your range by 10-15%. I have a ScangaugeII for my cng Honda Civic GX and I've learned that when I've reached the speed limit, no matter how fast or slow, I can ease off the pedal just a 'hair' and my MPG increases immensely (from low 30's to high 40's) and still maintain the same speed.

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So ECO mode = B mode?

Bicster said:

So ECO mode = B mode?

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I think we can only speculate at this point. I would imagine that ECO mode would do some (or all) of the following:

• Increase brake regen
• Decrease acceleration speeds
• Limit top speed
• Decrease cabin heating/cooling capabilities

As I think AndyH was hinting at, all of this can be done by the driver at any time. I would guess an ECO mode just forces this on the driver to help them be able to make it home.

Hypermilers out there probably are saying "ECO mode? We don't need no stinking ECO mode!"

Bicster said:

leaffan said:

From what I've read lately, I believe ECO mode increases the regen braking which gives you that extended range. All you have to do is ease off the accelerator pedal slightly to get extra regen. So even at hwy speeds (65mph) you could easily extend your range by 10-15%. I have a ScangaugeII for my cng Honda Civic GX and I've learned that when I've reached the speed limit, no matter how fast or slow, I can ease off the pedal just a 'hair' and my MPG increases immensely (from low 30's to high 40's) and still maintain the same speed.

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So ECO mode = B mode?

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If you're speaking of B mode as in the Prius, then no. That doesn't add regen, but adds engine drag. If you're speaking of B mode as in the Rav4EV then that sounds closer to the mark. Though I'm just shooting in the dark my guess is that Eco mode would limit torque in the Leaf. Maybe reduce AC compressor speed. And maybe add more regen. The torque reduction would be the biggie though. That's how I'd save energy in an EV. Well it IS how I save energy in my EV. I just use my right foot instead of pressing a button.

The new EV testing portal/page at the Idaho National Laboratory has two full-scale evaluations of the Nissan Altra EV. I just finished a quick read from the 2000 Altra test - there's also a report for the 1999 Altra.

The info is from Southern California Edison on-road and on racetrack testing - they evaluated the cars from a fleet-owner/operator perspective. The data is excellent! For example - in the report for the 2000 Altra, they did multiple runs thru their road loops with experienced EV drivers (more efficient) and 'Joe public' drivers and listed rang differences. There's a range of temperatures, the range of weight and electrical accessory loads, interior sound level tests, and a thorough look at changes from the earlier vehicle.

The 2000 eval has battery tech data - the early packs used the same LiMn variant of the Li-Ion family as the Leaf (though from two different manufacturers). The 1999 used analog battery management; the 2000 used digital. Geek Alert!

Enjoy!
Andy