Parade Driving

[patrick0101]

Like many other Leaf owners in the US, I had my car in a "End Dependence" Day parade today. I cleared the onboard counter and prepared to see some double digit miles per kWh numbers. I was expecting the miles of slow driving to boost my efficiency through the roof. I was wrong.

Most of the parade was a steady 3-4 MPH which was just right for keeping my foot off the peddles. This creep speed was the same in D or ECO. When the parade ended, my miles per kilowatt rating was 1.8. This is worse than driving at 55MPH.

Granted, parades are not a use-case that Nissan needs to optimize for, I was just surprised. If slow driving 30-38MPH is good, I thought really slow driving would be great. Electric motors do not have the limited RPM range of ICE but they do have bands for optimal efficiency.

 

[Stewy13]

As far as I've be able to gather from other members here on the forums, 35/38mph is the best speed you could drive at. Anything faster or slower than that will decrease your range or miles/kwh just because it's not efficient. Still surprising however that at those low of speeds you'd get that low of a number for your m/kwh.

 

[jhm614]

I would not have guess that! Could accessories (Lights, AC, Radio?) been a factor?

 

[TomT]

Parasitic losses are pretty much constant so they become a signification draw at very low speeds when motor draw is very low. Plus, the motor and inverter becomes less efficient at very low speeds. That is why Nissa says 38mph is the most efficient speed.

Most of the parade was a steady 3-4 MPH which was just right for keeping my foot off the peddles. This creep speed was the same in D or ECO. When the parade ended, my miles per kilowatt rating was 1.8. This is worse than driving at 55MPH.

 

[TomT]

Parasitic losses are pretty much constant so they become a signification draw at very low speeds when motor draw is very low. Plus, the motor and inverter becomes less efficient at very low speeds. That is why Nissa says 38mph is the most efficient speed.

Most of the parade was a steady 3-4 MPH which was just right for keeping my foot off the peddles. This creep speed was the same in D or ECO. When the parade ended, my miles per kilowatt rating was 1.8. This is worse than driving at 55MPH.

 

[tps]

If slow driving 30-38MPH is good, I thought really slow driving would be great.

"Do not expect all functions to be monotonic."

This topic has been discussed here, but most of the data comes from this Tesla source:
http://www.teslamotors.com/blog/roadster-efficiency-and-range

 

[DaveinOlyWA]

parade driving although slow, is still stop and go.

low speeds still have static overhead needs for accessories
low speeds do not take advantage of comparable regen (higher the speed, the higher the regen value)

low speeds dont take advantage of momentum cresting small elevations, etc.

ya, parade driving is very hard on cars. but at least yours did not overheat like gas engine cars tend to do

as far as most efficient speed, that is also weighed against the primary purpose of the car and that is getting from one place to another. without regard to traffic, roads, etc. the optimum speed for range is probably around the low to mid 20's