What is the actual miles from a full charge on the freeway

[evnow]

I was expecting to get a loss of 20% due to the freeway driving, not over 30% loss due to freeway driving.

Note that Leaf is rated by EPA at 73 miles and unlike ICE cars EVs suffer at highway speeds.

BTW, are you using climate control ?

 

[Kenkuramoto]

I was not using climate control. There was no wind of any kind. It was an ideal day for driving the leaf the only extra I had on was the radio. I was even driving in the city for approximately 10 miles of the drive which took only 2-3 miles off the battery range.so the loss was still more that the calculated range. the full charge said I had a range of 110 miles on the digital read out in the car.

 

[LEAFfan]

Those EPA figures are useless! Mark Perry told us that you should get at least 70 miles going no faster than 65.

 

[DaveinOlyWA]

It takes 47% more energy to drive at 70 miles per hour than it does at 60 miles per hour. Allow yourself a few more minutes at each end and you'll be fine.

I was taught it's the square of the velocity ratio... (70/60)^2=1.361. That's 36% more. What am I missing?

Malcolm

umm well for one thing speed is not divided in the that formula it the difference would be 70 squared - 60 squared is it not?

 

[TonyWilliams]

Why not just go by m/kwh instead of keeping track of bars and miles ?

I'm not sure exactly what your suggestion is. Each bar, we hope, is a somewhat linear 2kw, therefore 3.5mpk will get 7 miles per bar. Is that what you mean?

Counting bars gives you thresholds to estimate and meet, or if not, take the appropriate action to get things back on schedule (charge, change speed, etc).

 

[TonyWilliams]

Note that Leaf is rated by EPA at 73 miles and unlike ICE cars EVs suffer at highway speeds.

Certainly, and ICE suffers similarly, as any propulsion system would, to increasing the speed of the vehicle over the most efficient speed (reportedly 38 mph in our LEAFs).

That's the argument for the 55mph speed limit of the 1970's. The state of Montana did not issue speeding tickets in those days, and since the 55mph thing was a federal mandate for fuel conservation, they issued $5 "waste of natural resource" tickets that you paid on the spot. No points, no court.

 

[evnow]

Note that Leaf is rated by EPA at 73 miles and unlike ICE cars EVs suffer at highway speeds.

Certainly, and ICE suffers similarly, as any propulsion system would, to increasing the speed of the vehicle over the most efficient speed (reportedly 38 mph in our LEAFs).

True - but ICE is also bad in stop & go (atleast non-hybrids). That is why the city numbers are worse than highway. EVs are the otherway round - in the city they are better than on the freeway (except for mwalsh !).

While Prius, being a hybrid, suffers less from this - it takes time to warmup and give good mpg. That is why Prius isn't a great car if your commutes are short. The diff. between highway & city EPA numbers is only 6% (48/51).

 

[evnow]

Why not just go by m/kwh instead of keeping track of bars and miles ?

I'm not sure exactly what your suggestion is. Each bar, we hope, is a somewhat linear 2kw, therefore 3.5mpk will get 7 miles per bar. Is that what you mean?

I think we can now use the m/kwh to figure out the range quite accurately given all the empirical data. Multiply the m/kwh with 21.5 (or 20 to be conservative) to get the total range.

For eg. if you want a range of 75 miles, your m/kwh should be about 75/21~3.5 mpkwh. You should maintain that while driving (assuming your to & from numbers won't be dramatically different because of hills like mine).

Counting bars gives you thresholds to estimate and meet, or if not, take the appropriate action to get things back on schedule (charge, change speed, etc).

Yes, disappearing bars would be milestones to check - but with m/kwh you can check whenever you want or at certain landmarks on the way or every 10 miles or ... basically you get a lot more flexibility.

 

[DaveinOlyWA]

after the flash update, Nissan appears to want people to charge sooner.

so i have to say Miles per KWH is also the best way to determine your range especially when on freeway where performance #s are less likely to be affected by traffic, lights, etc.

 

[TonyWilliams]

I think we can now use the m/kwh to figure out the range quite accurately given all the empirical data. Multiply the m/kwh with 21.5 (or 20 to be conservative) to get the total range.

For eg. if you want a range of 75 miles, your m/kwh should be about 75/21~3.5 mpkwh. You should maintain that while driving (assuming your to & from numbers won't be dramatically different because of hills like mine).

Neither method must be exclusive of the other. Also, if you aren't starting with a known value, like a full charge, you are counting bars.

 

[leafme]

It takes 47% more energy to drive at 70 miles per hour than it does at 60 miles per hour. Allow yourself a few more minutes at each end and you'll be fine.

I was taught it's the square of the velocity ratio... (70/60)^2=1.361. That's 36% more. What am I missing?

Malcolm

umm well for one thing speed is not divided in the that formula it the difference would be 70 squared - 60 squared is it not?

hmmm... but that just gives you 1300 with units of mph squared. no? I'm still thinking the 36% increase in energy is correct still (but still might be convinced otherwise).

Macolm

 

[evnow]

hmmm... but that just gives you 1300 with units of mph squared. no? I'm still thinking the 36% increase in energy is correct still (but still might be convinced otherwise).

Using the famous Tesla graph ...

Aero losses are 150 w/mile @ 70 mph, 50 w/mile at 40 mph.

(70/40)**2 = 3
150/50 = 3

So, yes, the energy spent at 2 speeds is proportional to square of the ratio of the speeds.

The total energy spent @60 mph is 250 w/m and 70 mph is 300 w/mile.

(70/60)**2 = 1.36
300/250=1.2

So, doesn't translate into total energy spent (not surprising given other losses).

Original post said

It takes 47% more energy to drive at 70 miles per hour than it does at 60 miles per hour. Allow yourself a few more minutes at each end and you'll be fine.

(300-250)/250 = 50/250 = 20%. Not sure how that 47% was calculated.

In other words, both 36% and 47% are wrong. Tesla graph shows 20% more energy consumption @ 70 mph compared to 60 mph.

So, if Leaf is like a Roadster, I expect the range to go from 70 miles @ 60 mph to 58 miles @ 70 mph.

 

[turbo2ltr]

I recently did a trip which was 75 miles, all but maybe 5 miles were highway. I ended with 3 bars, 27miles and 28% SOC left (old firmware). I did pretty much did 55 in the 55 and 60 in the 65 though in the beginning I was behind a truck doing around 50 for several miles. AC was off. Lights were on for the return trip. Started at a little less than 100% battery. Whole trip was pretty flat overall. It was the farthest I had gone in a single-trip. I was pleasantly surprised I had no problem. I've returned from much shorter trips with much less battery left.

 

[starry]

My round trip distance between San Clemente, CA to Vista CA residence is 67 miles. An elevation change of -250 feet is at start, and I get a little bit of regen. About 80% of the distance (53 miles) is on I-5 and CAL 78 freeways. Three times I did the trip without recharging--speed of no more than 54 mph on the freeways. At 100% charge, I finished with 2 bars or 13-17 miles range left on the updated bars display (some reserve left below last bar). One other trip, there was a bus fire on I-5, bad traffic from lookyloos meant 12 miles were at no more than 30 mph. I think if I went 55-60 mph I could just make it with no bars. And the freeway experience at 55 or less means driving through the rear view mirror most of the way.
A better indicator of range and cost is my electric bill for May; the first four weeks of charging the car at home shows a 30 dollar increase for about 700 miles driven. Comparing my old minivan's cost of 140 dollars for OPEC gouge, LEAF economy pays for about a quarter of the car payment.

 

[TonyWilliams]

So, if Leaf is like a Raodster, I expect the range to go from 70 miles @ 60 mph to 58 miles @ 70 mph.

Almost precisely what my chart predicts.

http://www.mynissanleaf.com/viewtopic.php?f=31&t=4295

 

[Caracalover]

Try time as a gauge.

If you use 20KWH as your fuel tank (4k safety) you can drive for an hour using 20k, half an hour at 40k.

Watch the power meter screen and adjust accordingly. Creep likely uses 1 or 2 k that doesn't really show on the screen but I would think 20 hours is an unlikely scenario anyway. You also need to factor in the other power uses, but with 4k spare it is not a major issue.

At 80k you run out of zap in just 15 minutes, but I would think you would need four flat tires to do that.

If you regen 10k for 30 seconds, you can add 15 seconds at 20k.

Coasting is free time.

 

[Herm]

And the freeway experience at 55 or less means driving through the rear view mirror most of the way.

Cover up the rear view mirror with a towel and it wont bother you, if you get lucky and someone tailgates you then even better since it may lower your drag.

 

[pearlyleaf]

I did a 70 mile RT highway drive recently, relatively flat, down the peninsula and back. Started with 111 mile range and ended with ~10 miles. I drove in ECO mode 90% of the way, had my AC on and kept my speed @ ~65 mph. I did not get the "turtle sign" so I guess the battery wasn't too low?

I would have preferred to have charged my car at my destination, because I did feel some "range anxiety", but us early adopters will just have to wait for the build-out... :roll:

 

[TonyWilliams]

I did a 70 mile RT highway drive .... Started with 111 mile range and ended with ~10 miles.

The Guess-O-Meter range readings have very little benefit. I recommend just covering up the readout with a sticker. Use range bars until there is a viable "gas gauge" that is available.

 

[planet4ever]

I did a 70 mile RT highway drive recently, relatively flat, down the peninsula and back. Started with 111 mile range and ended with ~10 miles. I drove in ECO mode 90% of the way, had my AC on and kept my speed @ ~65 mph. I did not get the "turtle sign" so I guess the battery wasn't too low?

No, you were nowhere close to the turtle. The sequence is:

1. A lady with a nice voice tells you your battery is low, and the range number starts flashing. This will happen sometime after you drop to 1 bar, and the range will probably be showing somewhere between 5 and 10.
2. About five to ten miles after that, the lady will tell you your battery is very low, and suggest you find a charging station. The center console will switch to a map showing you nearby charging stations. The range number will disappear, replaced by three dashes. You will have lost the last bar before this happens.
3. Another five to ten miles down the road the turtle will light up, and you will suddenly have very little power. If this happens you need to look for a safe place to stop off the road. You could probably keep going for half a mile or so, but not much more than that.

Since you had not seen or heard any of these things yet I would expect that the battery still had a good 15 to 20 miles of juice left in it.

Ray