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72.9 Miles on One Charge

30K views 40 replies 24 participants last post by  2BeLivingGreen 
#1 · (Edited)
As regular readers will recall, last Monday I posted this thread about going 63.9 miles on one charge. For the entire trip I slowly accelerated in D to 40MPH, dropped it into N to coast down to 25MPH, then back to D to slowly climb back to 40MPH etc. My average speed for the trip was 32 MPH.

Today I tried a different method (which was suggested by bonaire and bookdabook): Set the cruise control to 32 (in Drive) and forget it.

Started out at 5AM, 72 degrees:

Electronics Multimedia Technology Screen Electronic device
Auto part Technology Electronics Electronic device


You'll note I started with 41 miles of electric range because yesterday I made a 300 mile trip going 65 MPH, so the computer wasn't expecting me to drive slowly. But it quickly recalculated! After a full 16 miles of driving at 32 MPH, the battery icon had removed two green bars, but it now showed 46 miles of electric range!

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Ended 2 hours and 22 minutes later and 72.9 miles later (avg. calculated speed = 30.8 MPH). Ending temp 75.

Electronics Multimedia Technology Electronic device Vehicle
Electronics Multimedia Technology Electronic device Car


The two changes since my last hypermiling attempt were the driving style and the temp, which was about 15 degrees warmer today. The rest of the variables were the same: Same road, same average speed. No Mountain Mode, no additional charging. Tires at 51 PSI. No climate control, radio, or headlights. Windows up. Round trip to eliminate elevation impact.

If you study the screenshots carefully, you'll note that I started with 66 miles of gasoline range, and ended with 89 miles of gasoline range, so it appears that the gas range is re-calculated based on driving habits just as the electric range is. Could be dangerous if you are driving 35 MPH for an hour and a half, then start going 75 MPH, your range is going to drop quickly.

Now I'm wondering what it would look like with cruise set to 25 MPH the whole time. And also what 35 MPH and 40 MPH would look like...
 
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#2 ·
Outstanding work and great mileage outcome! I must admit I would have never guessed you could have bettered a 63.9 mile range by a full 9 more miles! I have to be thinking a few of the GM insiders which made a lot of key energy calculations in the development process on the VOLT are secretly saying Yesssss! as you have proved what they saw/envisioned as a true potential yet could not state since it was not an expected daily drive routine.
These forums provide a lot of good info and just goes to show the potential of sharing info (in this case how you drive can make a big difference).
 
#3 ·
Well, I just started it back up to pull it in to the garage, and now the display once again shows 66 miles of gas range. Looks like it recalculated, and assumes I'm done with my 32 MPH experiment! And of course it is correct! What a smart car, it knows what I'm thinking...
 
#4 ·
Thanks both for taking the time -- not a quick trip -- and for sharing. Very interesting though not surprising results. Avoiding accelerations is a good thing. No way I could get this number. Too many hills and too much traffic. But it's great fun to see what you've managed to do. Congrats!

My prediction would be that 25 MPH would give better range and that 35 MPH or 30 MPH would be so close to 32 MPH that other variables like temperature would mask the result. Assuming you could measure accurately, 30 MPH would be better and 35 MPH would be worse.

More interesting would be to see how much of a difference "Power Pulse and Glide" makes.
 
#5 ·
Nice experiment; thanks for posting the results. It really shows the effects of drag (which increase much faster than linearly with speed, and the power to overcome drag increase with the cube of the velocity!).

A question: when the computer recalculated your range (both electric and gas), did it change the (analog) displays of bars, or just the (digital) display of miles remaining? Yours is the most dramatic recalculation I've seen (mine have been pretty subtle: a mile or two difference here and there).
 
#6 · (Edited)
Fantastic , your mileage numbers are amazing ! I wonder what top number GM was able to achieve on their test track ? Don't you wish there was a software upgrade we could download to increase our 'un-used' battery potential by a few percentage points without shortening the life of the battery. Maybe there is a compromise number better than what is now used.
I should give hyper miling a try here where it is flat as a board to see if I can even come close to your incredible numbers.

Steve in Boca Raton #313

P.S. I need to break my personal record of 48.5. I know now that I can do it easily, I just have to take the time to do it ( and get up early )
 
#7 · (Edited)
I wonder if you could repeat for every mph between 32 and 40 :) And graph it :) I thought maybe you had gone to 62 psi on the tires...

Awesome results. Given that this is a sweet spot of momentum versus drag, you may find somewhere between 30 and 35 on cruise control is the best possible. There's a lot of country roads near me with 35 and 45 mph zones which people routinely run at 45-60mph. If they only knew driving the speed limit was actually good for their mileage.

THere are charts on the Tesla web site showing the combination of effects of aero-drag, friction, etc. If they also would consider air density in the factor. A low humidity day of say 72*F and 20% humidity (like right here, right now in SE PA) would be perfect. Higher humidity and cold air are heavier and harder to push through. When I was a cyclist, I paid very close to these attributes of the day to know how far we could ride.

Speed = horsepower required. So, EVs don't need a lot of horsepower to go slower. Heck, the Amish buggies around my area only need one horse to pull the cart and four occupants about 10 mph. :)

PS - though this shows some extreme goodness for the Volt, it also means someone with a Leaf will be able to pull-off maybe a 140mile run with these settings. But they better end at-home or a charging station somewhere down the line.
 
#13 ·
PS - though this shows some extreme goodness for the Volt, it also means someone with a Leaf will be able to pull-off maybe a 140mile run with these settings. But they better end at-home or a charging station somewhere down the line.
And wouldn't that be a fabulous thing--really, not sarcastically--for the EV and EREV market? Some publicity about the real potential of these cars to start to quell the range anxiety would be helpful. (Too many people still believe that Volt drivers suffer, or should suffer, from range anxiety. Too many people equate any form of "electric" with "limited use, limited potential.") Unfortunately, someone would almost certainly then stage some kind of publicity stunt in a Leaf, invite the press, set off on a 140 mile run, and then blow it somehow and wind up a couple miles short, stranded, and we'd be worse off than we started.
 
#8 ·
Imagine driving across country, what would the fuel mileage be? It would be the ultimate Sunday drive and the drivers behind you could get a bit upset!

If peak oil causes major shortages, maybe those high occupancy lanes will be turned into 40 mph EV lanes!

What is important is for those who never get above 40 miles. They can make changes to their driving style and improve the range. Local drives with full heat or air ruin my range. The moderate speed freeway drives work nicely.
 
#9 ·
Next you needs to see if you can get even more range by buiding a long straight highway on the moon and seeing how far you can go without any atmosphere and 1/4 gravity. I am betting you can top this record!
 
#10 · (Edited)
Perfect use of the Volt in this scenario would be a chase vehicle for the RAAM - Race Across America bicycle race. The guys are basically cruising along at 20-25 or so, west to east (CA to MD). You could charge up during a 2-3 sleep hour stop at a 220v charger and do 50+ miles then maybe 48 mpg in CS mode. The bikes are not allowed to draft a vehicle for speed, but it would be nice to have a Volt as a sponsored chase vehicle to illustrate new green technology. Yes, they do ride 20-22 hours a day and sleep 2-4 hours. Many chase vehicles are mini-vans, however, due to carrying spare parts, food and equipment.

http://www.raceacrossamerica.org/raam/raam.php?N_webcat_id=1
 
#18 ·
Perfect use of the Volt in this scenario would be a chase vehicle for the RAAM - Yes, they do ride 20-22 hours a day and sleep 2-4 hours.
But when and where would you recharge? I don't think a Volt would have enough room for sleeping drivers, mechanics, etc. But a Voltec minivan........

WVhybrid
 
#11 ·
Thank you for taking the time to do this experiment and post the results. I too wish GM would post an efficiency graph, so we could see the amps required and range available at various speeds. For now, you are creating that graph for us, one trip at at time. I am very interested to see what your results are at 35 MPH, 40MPH, 45MPH....

Thanks again! :)
 
#12 ·
Superb effort at pushing the limits upward. I'll be you could jump it into the 80's if you'd be able to tailgate a van going 30-35 mph.
 
#14 ·
One (small) observation is that humid air is actually less dense than dry air. Allied pilots in WWII found out about this when their ICE powered planes were not delivering rated power and performance in the Pacific. Investigation found that the high humidity was causing a loss of performance in not one but two ways. Firstly, humid 'thinner' air meant that the takeoff distances were longer because the airplanes had to accelerate to higher (true) airspeeds on takeoff in order to reach the same "indicated" liftoff speed and, secondly, the water vapor in the air displaced some of the oxygen, thus reducing the power output of the engines.
 
#15 ·
On a practical note we find that driving in Miami's heavy traffic and long red lights actually has been adding at least 15 miles to our charges. We always drive in low and the Miami weather has been cool and dry enough to be comfortable with the windows open. (I do wish we could eliminate the buffeting though). The re-gen in LOW is a big help during city driving. Just make sure you tap the brake pedal lightly to keep the guy behind you from joining up.
 
#17 ·
Crack one side of the back window open and there's almost no buffeting.

Highway speeds kill range as proven by this thread, so no surprise on your personal observations.
 
#19 ·
Actually, I could beat this without trying. I charge regularly during the day. I've noticed if I don't completely recharge the battery (I have to go somewhere else) the "this charge" screen doesn't reset. So, I've had it say several times 50 or 60 miles. Validating this in your hypermiling contest may be difficult.
 
#20 ·
I personally believe honoreitiscom to be truthful, but the43k raises a good point about the need for some form of validation for the rest of us wannabe hypermilers. I wonder if Onstar could provide that validation? Does Onstar have the ability to check distance travelled and time since last plug-in, and could that information be sent upon request to the owner's email? Having some form of indisputable validation might benefit Chevy and even the whole EV industry, proving to the naysayers that careful hypermiling could DOUBLE(!!) the range of EV vehicles. I hope the Chevy publicity people are paying attention.
 
#21 · (Edited)
I don't think it helps much with the naysayers to published what amounts to "lab" results.

No one is going to get 70+ miles per charge in "real world" conditions.

The main point to naysayers is that even if you are only getting a conservative 35 miles per charge and 35 miles per gallon after that with spirited, heavily climate controlled driving, and you have a longer than average commute at 70 miles roundtrip with no ability to recharge at work, you are still getting 70mpg, which is incredible.
 
#22 ·
There's hypermiling and then there is back-road regular driving. I have a variety of roads in the 35-45 mph range and the Volt should shine in those conditions. At least 45-50 miles per charge for those road conditions. Not all of us use a highway during a commute. For my telecommuting, the mileage is 0 and currently, mainly driving around town for errands. Occasional drives will be to an office in NJ which is 60 miles away and could allow for plug-in recharging there.

No Volt yet - but it is a good fit when I can swing it.
 
#23 · (Edited)
If we set aside criticism of the EPA's assumptions and just use their assumptions as the "industry standard" used to compare different cars, then I figure I got 194 MPGe.

According to the Volt EPA window sticker, the Volt gets 36 kWh per 100 miles, or .36 kWh per mile. EPA also says the Volt gets 35 miles per charge. .36 kWh x 35 miles = 12.6 kWh per full charge (which is a little higher than the 12 kWh I see on my TED, but I suppose it is higher when cold out).

My 72.9 miles / 12.6 kWh = 5.786 miles per kWh. EPA says 33.7 kWh = 1 gallon of gas. 12.6 kWh / 33.7 kWh = .374 gallons per full charge. 72.9 miles / .374 gallons = 195 MPGe.

Another way to get approximately the same result: EPA says the Volt gets 93 MPGe and 35 miles per charge. I went 72.9 miles / 35 miles = I did 2.08 times better than EPA. 93 MPGe x 2.08 times better = 193 MPGe.

And as long as we're calculating... I pay $0.10 per kWh, so I paid 12.6 kWh x .10 = $1.26 to go 72.9 miles. At that speed and temp (31 MPH, 75 degrees) my old Prius would have gotten ~70 MPG. 72.9 miles / 70 MPG = 1.04 gallons x $3.75 per gallon = $3.90, over 300% more than I paid for electricity to go the same distance.
 
#24 ·
Somehow I missed this thread when first posted! Todays post complimenting honoreitiscom made me search for it. My only question is where in the country and what type of roads permitted a two hour trip at 30 mph?? Could not do that in SoCal very well.
 
#26 ·
RonC:
I'm guessing that your drive is street-hw-street, and probably pusing 70 or more on the HW. Since you know you are going to use the CS on the way back, you might consider doing some MM to see if you can get above 35m. You might try starting with Mountain Mode, so will get 16-18m before the ICE starts. Then "turning off MM when you get off the highway, then drive the rest of they way normall. Should have enough CD range to do the slow-speed and stuff off the HW and back to it, and then the ICE will start again on the way home. I play more agressive MM modes (based on terrain.. mentioned in another thread). I'm doing this on my trips to the airport, averaging 42 miles in CD mode and using 1.9 or 2 gallons MPG CS (for about 84 miles of CS).
 
#27 ·
That's exactly right - it's about 10 miles on surface streets then almost 25 on a highway at "the posted speed limit" (and just maybe a smidgen above ;) ) followed by <1m to arrive at my office; the return trip is the opposite. I was thinking about MM during the highway portion to finish up with enough battery to be mostly CD miles for both tail-end surface street legs.

I don't have my Volt yet (patience, Grasshopper) but I'll probably be spending the first month experimenting with different methods of minimizing my gasoline consumption on that commute. As an engineer, I'm already predisposed to over-analyze this, so expect a 5 page paper with the requisite graphs and data. Two variables I won't be able control are weather and traffic; they're not fully independent, but they are outside my control.
 
#28 ·
I am considering a Volt purchase but after reading the Car and Driver comparison with the Chevy Cruze, I am puzzled by the steady state mileage figures using only ICE. The article shows that increasing your speed from 40 to 70 MPH will result in improved mileage figures. Can this possibly be true?? Has anyone out there really camped out on the engine only steady state mileage capability of the Volt like what honoreitiscom has done with the battery range? If C&D is all wet with their data, they need to publish a retraction!
 
#30 ·
I am considering a Volt purchase but after reading the Car and Driver comparison with the Chevy Cruze, I am puzzled by the steady state mileage figures using only ICE.
The article is one of those "Man Bites Dog" stories. All you have to do is look at the EPA figures where the Volt gets better MPG than the Eco Cruze when running in gas mode for all cycles to know the story line is silly. The graph you're referring to seems to be a graph of engine efficiency. It may be accurate but it doesn't translate into practical MPG numbers because overall efficiency is determined not only by how efficient the engine is but by how much energy you'll need to maintain a given speed. IOW you'll get vastly better MPG at 40 MPH than at 68 MPH despite the fact the graph says the engine is most efficient at 68 MPH.

If you want to see real world numbers check out http://www.voltstats.net. The Cruze won't even begin to approach these numbers.

FWIW I think the magical MPH number GM has used as a fuzzy line when the small motor/generator provided counter torque to the ring gear is 70 MPH.
 
#29 ·
I don't think it is true, but I haven't seen any details on their testing. I wouldn't be surprised if going from 40 to 50 improved the mileage, because in between the two the Volt switches modes to allow the mechanical connection between engines and wheels. I'm quite certain from the driving I've done that it is noticeably more efficient at 60 than 70 either CS or CD, however.
 
#34 ·
Wind resistance goes up exponentially above 30-something MPH. Unless something is wrong in the design that would reduce low speed mileage (or you're drafting a big truck) no way you do better at higher speeds. Yes, I'm a physicist. I do rocket surgery every day.

Now, I live near the top of a mountain. When I go to town, I go downhill for about 4 miles, fairly steep - I use low gear to keep speed under control. The I go along a river, down river, for another 4 or so miles. I get to that 8 mile point with a full charge still. I almost wonder if I should bother charging it all the way up, as perhaps I'm not getting as much regeneration as I could with an already-fully-charged battery. They'd have to limit how much they would overcharge it, right? I guess I'll test that one.
 
#35 ·
Wind resistance goes up exponentially above 30-something MPH. Unless something is wrong in the design that would reduce low speed mileage (or you're drafting a big truck) no way you do better at higher speeds.
...
perhaps I'm not getting as much regeneration as I could with an already-fully-charged battery. They'd have to limit how much they would overcharge it, right? I guess I'll test that one.
Drag goes up with the square, power to overcome the drag force with the cube. Yeah, a 10% or 15% increase in engine efficiency when going from 40 MPH to 70 MPH won't make up for the increased power you'd need.

Early on I remember that GM said one advantage of using less than 80% of the battery would be headroom for regen even when the battery was fully charged from the wall. In four miles I suspect you won't regen enough to use up that headroom. Also note that below .1g you're primarily using the mechanical brakes, so if you're going slowly downhill regen may not be that effective regardless of the SOC.
 
#40 ·
Congrats and a question on tire Pressure

This is an amazing outcome. Where was the travel done so we can judge the terrain in terms of hillyness. I assume that you did no Neutral coasting, even on the down grades per your very carefully described experiment, including the earlier one using 40 to 25 pulse&glide.

I have a destination that is 48.2 miles from home and my goal is to see if I can "get there" on EV only mode. Can't wait for it to warm up a bit.

Now for the question. Was the 51 psi the cold pressure? Or was that the live readout pressure the car provides that shows that at speed, the pressure rises? I typically see 42 psi go to 45 psi while driving in 45 F temperature.

Best of luck with your methods.
 
#41 ·
Dave2012, You should be able to have several successful EV only trips with a destination of 48.2 miles. In the summer (late spring to early fall) I had almost daily occurrences of 48 miles on EV only. I had a personal max of 52.3 miles. These were all with tires at 38 psi, no pulse and glide, just driving. The 52.3 trip did not start out to be a record, but a little more than half way through my trip I realized I was getting very good range so it was not until then that I tried to maximize my EV miles by taking non freeway roads.

So in the summer I would often run 48-49 miles very consistently. So your drive is likely rather achievable.
 
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