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Discussion Starter #1
So last Friday, I made the round trip from home in SF to Thunder Valley Casino, a one-way drive of almost exactly 120 miles. I began from home with a full battery. I filled up while there for the trip home. Each leg of the trip was rather different.

The trip is almost completely by freeway. There is virtually no net elevation change; Lincoln, CA, is officially 167 feet above sea level, and my home can't be much more that 100 feet above sea level. I did hit a couple of traffic jams on the trip out, so some regenerative braking did get added to the mix. Both ways, unless there was traffic, I set the cruise control at 68 MPH, and when the cruise control was off, I tried to maintain about the same.

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Here you can see the GOM upon arrival at the casino. A very surprising 4.3 mi/kWh. And an estimated 126 miles of range left.

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Here you can see the GOM upon arrival home. a miles/kWh average MUCH less than the trip out. And only 92 miles of estimated range left.

The only thing I can really think of to account for the difference was wind. As best I could tell, there were places on the trip out that seemed to be giving me a tailwind. And on the trip back, it was pretty clear that I was hitting some spots with a headwind, sometimes strong enough to cause not a little buffeting.

This is neither good nor bad, but data such as this is interesting. And for trip planning, data to help manage charging stops when going into places where you can expect windiness.
 

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In my experience, wind is the #1 factor to account for with the Bolt EV in terms of range and efficiency. Elevation gain is also a factor, but you can plan around that. Wind is a little more difficult. And despite some claims, an A to B to A trip doesn't account for the effects of facing a headwind in one direction, which more than offsets the gain you'd see in the opposite direction from a tailwind.

Overall, though, you're looking at close to a 3.9 mi/kWh average (about the Bolt EV's EPA estimated combined efficiency), and that's about right for round trip efficiency I expect on a 65 to 70 mph trip.
 

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A total range of 214 on the way back is pretty good, too, coming from someone who has done a similar drive and gotten much worse efficiency. Granted, I have a heavier right foot but the differences in range for these two legs is very interesting.
 

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I have always wondered why EVs don't have an air speed indicator. They are not expensive, and would give us an immediate heads-up. Much better than waiting to see the GOM readjust miles down the road.
 

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When flight planning, one always looked at the wind forecast or one might run out of fuel.

At ground level the wind speed and direction can be more variable. I use the old Buford scale.

 

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I generally just do a quick check the weather report for the route so I'm not taken by surprise. Driving 500+ miles tends to result in driving through multiple different weather zones.

I think accessing wind data from outside the car is going to be far more accurate overall, but ultimately, I rely on the consumption data displayed on the DIC. If I'm driving 70 to 75 mph and my consumption is reading 25 to 30+ kW, I know the wind is significant. Of course, this requires having at least a basic knowledge of the lay of the land (i.e., elevation increases and decreases).
 

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Headwinds, definitely could explain it. Temps?

If you left SFO in the early morning and drove through Sacto before the heat of the day, then returned during the heat of the day, you might have used AC, and\or battery conditioning. The Central Valley can get warm this time of the year, like over 100 pretty regularly.

Li Ion batteries are most efficient in the 60-80F range.
 

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Headwinds, definitely could explain it. Temps?

If you left SFO in the early morning and drove through Sacto before the heat of the day, then returned during the heat of the day, you might have used AC, and\or battery conditioning. The Central Valley can get warm this time of the year, like over 100 pretty regularly.

Li Ion batteries are most efficient in the 60-80F range.
True, I’m in Sac and it’s been between 100 and 105 here for the last two weeks or so.
 

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At those speeds, AC should account for at most 8% to 10% of the total energy consumed, so it could account for part of the difference but not all.
 

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I've experienced wind affecting ICE fuel mileage. Once heading north with a new used car, I was pleasantly surprised with the mileage readouts on the dash panel. Turns out there was a substantial tail wind. When I turned west, the cross wind made driving a bit of a PITA and dropped the fuel economy back to slightly below expected.

jack vines
 

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If you want to see 5 plus miles per Khw draft a truck 4-5 car length behind is good enough. The reduction in aerodynamic drag is massive.
 

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Discussion Starter #13
Headwinds, definitely could explain it. Temps?

If you left SFO in the early morning and drove through Sacto before the heat of the day, then returned during the heat of the day, you might have used AC, and\or battery conditioning. The Central Valley can get warm this time of the year, like over 100 pretty regularly.

Li Ion batteries are most efficient in the 60-80F range.
A ran a nice long day of poker and then had a satisfying Fatburger afterward, so in this case, I dind't begin the drive home until after sunset and temperatures were dropping into the 80s up there.
 

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If you want to see 5 plus miles per Khw draft a truck 4-5 car length behind is good enough. The reduction in aerodynamic drag is massive.
I learned that as a hypermiling technique with my past hybrids. Can also get this effect at a certain spot alongside a front wheel. But that close at 70 MPH is out of my comfort zone, and interestingly, saw very few large trucks on the trip.
 
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