How I (kind of) set a range record in the Chevy Spark EV

[CopperRoad]

Fun article...

http://www.digitaltrends.com/cars/spark-ev-world-record/

 

[TonyWilliams]

I'm surprised that it only went 139 miles.

Edmonds did a track test like this with a LEAF at 35mph for 132 miles.

We have one driver who drove a LEAF for 188 miles!!!

http://www.mynissanleaf.com/viewtopic.php?p=154572#p154572

 

[gra]

I'm surprised that it only went 139 miles.

Edmonds did a track test like this with a LEAF at 35mph for 132 miles.

We have one driver who drove a LEAF for 188 miles!!!

http://www.mynissanleaf.com/viewtopic.php?p=154572#p154572

Consider the conditions, though: 40 degrees, Portland on what looks like a wet track, probably stock tire pressures, 24 mph versus 18 or so. LEAFfan probably would have managed the same or less, and I imagine he's got a lot more practice hypermiling.

 

[Nashco]

I would expect using a road course for an maximum range test doesn't help...you scrub a surprising amount of energy changing directions with a car, even at low speeds. Don't believe me? Push a car on flat ground in a straight line and stop. Then turn the steering wheel and try the same thing...takes a lot more effort!

Having a warm battery and transmission would make a noticeable difference. Also, tires have maximum rolling resistance when new, so a set of tires that is well worn (or new shaved tires) will result in noticeably lower rolling resistance as well. All that squirming rubber wastes energy.

Anyway, there are lots of ways to improve...feel free to take all of these ideas for the next challenger to this semi-official record!

Bryce

 

[TonyWilliams]

Anyway, there are lots of ways to improve...feel free to take all of these ideas for the next challenger to this semi-official record!

Bryce

1) Drag - Wind resistance - high elevation and hot ambient temperatures thin the air, making it easier for any object to pass through the air. In the airplane business, we call this calculation "density altitude". Here's an easy to use online version: http://wahiduddin.net/calc/calc_da.htm. The most "aerodynamic" vehicle will cut through the air with the least resistance.

2) Drag - Rolling resistance - drag from everything that rotates to move the car; tires, wheel bearings, u-joints or cv-joints, gears and bearings, gear lubricant. Generally, the hotter the lubricant, the lower its resistance; the higher the tire air pressure, the lower the tire resistance.

3) Gravity and Mass equals Weight - as long as there is gravity, it will take energy to accelerate mass and energy to propel mass at speed. Obviously, it also takes significantly more power to lift the mass away from the gravitational pull while driving uphill. Quite simply, lighter is better.

4) Ideal speed - every vehicle has a speed where the intersection of the power required to overcome drag and weight is the least. Heavy cars with high drag tires (but extremely aerodynamic) like a Tesla tend to be most ideal in the 20-25mph range and small, lower mass cars like LEAF and Spark EV are probably in the 10-15mph range. Obviously, anything that uses power that isn't being used to overcome drag and weight is a waste; the heater, a/c, etc.

5) Hot batteries store more energy - the hotter the better, however, this same heat tends to significantly shorten their life (Nissan LEAF in Phoenix) and in some cases (Boeing 787), make the battery fail.

That's it! Hit the ideal speed, at the lowest weight with the least drag and the most stored energy!!!!