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[Doctorbass]

Today i tested with good accuracy the consumption of my DS 2011.

I tested it on what appear to be a flat paved road (no apparent slope).

- wind of 15km/h in one direction ( i did one pass in each direction and then calculated the average)
-Outdoor temp was about 10 Celsius
-Both tires was inflated to the specified pressure of 32psi front and 35psi rear
-I weight 150 pounds
-I was wearing a large Angora jacket and a aerodynamic full face Arai helmet
-My zero dont have any wind screen

The power usage can be calculated easy by multiplying the Wh/km by the speed... ex: at 100kmh, the Wh per km is 96.25 so the power is 9625Watts

I made a graph of what i got:

UPDATE 2016: here is the excel formula i made out of it: Wh/km =(15,866 * EXP(0,0182*kmh))/1000 

Doc

[firepower]

Good to see you using real units, metric and not ancient imperial units 

[NoiseBoy]

Great job Doc,  How long was the sample at each speed?  Have you worked out the optimum cruising speed for the bike?

[protomech]

Very cool, thank you!

@ 4000 Wh nominal capacity, works out to the following ranges:

30 km/h (19 mph): 142 km (89 miles)
40 km/h (25 mph): 121 km (76 miles)
50 km/h (31 mph): 100 km (62 miles)
60 km/h (37 mph): 83 km (52 miles)
70 km/h (44 mph): 70 km (44 miles)
80 km/h (50 mph): 58 km (36 miles)
90 km/h (56 mph): 49 km (30 miles)
100 km/h (63 mph): 40 km (25 miles)

You said earlier that you were seeing 3000 Wh actual available capacity from the 2011 battery, which would cut all of the above ranges by 25% (ish).

[benswing]

Doctorbass, you're my hero!  Thanks for the data!

So far I have an average of 123Wh/mi (76.3Wh/mi) on my 2012 Zero S.  Apparently I ride fast a lot. 

THIS would be useful data for potential buyers to have.  Then it would be easier to figure out range at different speeds.

[BSDThw]

Nice, you can see how the air resistance raise consumption in Power of two.

If I got it right you will use a wind screen soon. So it would be very interesting to repeat it with the wind screen.

 

[trikester]

30 km/h (19 mph): 142 km (89 miles)
40 km/h (25 mph): 121 km (76 miles)
50 km/h (31 mph): 100 km (62 miles)
60 km/h (37 mph): 83 km (52 miles)
70 km/h (44 mph): 70 km (44 miles)
80 km/h (50 mph): 58 km (36 miles)
90 km/h (56 mph): 49 km (30 miles)
100 km/h (63 mph): 40 km (25 miles)

This is great information, thanks to both of you!

Of course I knew of the speed to power use relationship, but it is great to see the numbers and the graph. I have mentioned before that I get much more distance dirt riding than I do on the highway even though I usually hold my highway speed to 35 - 40 mph (those imperial units again). I've noticed that on many of my dirt rides average speed is around 15 mph which is more than just cancelling the higher rolling resistance in dirt and rocks and much lower tire pressure (10 to 15 lbs in front, 15 to 20 rear). It's actually adding distance above that.

On my 50 mile, 2000 ft climb / descent, all dirt ride last year (2012 DS ZF6), average speed 17 mph, I had 1/3 capacity left so I could have done 75 miles. I've never seen mileage like that on the highway, even with my conservative 35 to 40 mph riding speed.

Trikester

[benswing]

Doctorbass, you're my hero!  Thanks for the data!

So far I have an average of 123Wh/mi (76.3Wh/mi) on my 2012 Zero S.  Apparently I ride fast a lot. 

THIS would be useful data for potential buyers to have.  Then it would be easier to figure out range at different speeds.

[BrianTRice@gmail.com]

Today i tested with good accuracy the consumption of my DS 2011.

I tested it on what appear to be a flat paved road (no apparent slope).

- wind of 15km/h in one direction ( i did one pass in each direction and then calculated the average)
-Outdoor temp was about 10 Celsius
-Both tires was inflated to the specified pressure of 32psi front and 35psi rear
-I weight 150 pounds
-I was wearing a large Angora jacket and a aerodynamic full face Arai helmet
-My zero dont have any wind screen

The power usage can be calculated easy by multiplying the Wh/km by the speed... ex: at 100kmh, the Wh per km is 96.25 so the power is 9625Watts

Thanks for the methodology! I'll see about this with my 2013 DS and see what figures I get. I'm especially interested in how much the rider profile affects efficiency at different speeds. Now I just need to find a straight, flat, smooth road in the Seattle area...

[Doctorbass]

Great job Doc,  How long was the sample at each speed?  Have you worked out the optimum cruising speed for the bike?

I did each run until the Wh/km was constant and not changing ( about 1km on a flat street)

No research for optiomum cruising speed yet but will determine soon!


Doc

[Doctorbass]

Nice, you can see how the air resistance raise consumption in Power of two.

If I got it right you will use a wind screen soon. So it would be very interesting to repeat it with the wind screen.

Yes i will DO IT as well !!

I am just looking for a wind screen that is not too big ( Dont want a too old custom motorcycle look) and i'm searching more for a racer style wind screen..

Doc

[Doctorbass]

The Wh/km is measured with my Cycle analyst display device( http://www.ebikes.ca/drainbrain.shtml.

To instal it i had to add a shunt to measure the current flow between the battery and the controller, to connect the speed sensor on the motor tach sensor signal, and finally to connect to the battery voltage output on the controller. by that way i get every usefull data. (see the install here:)http://www.endless-sphere.com/forums/viewtopic.php?f=10&t=40849&p=620686&hilit=cycle+analyst+zero#p620686

DOc

[BrianTRice@gmail.com]

The Wh/km is measured with my Cycle analyst display device( http://www.ebikes.ca/drainbrain.shtml.

Okay, that's more involved than what I try in the short term! Could you try the test with a leaned-forward riding position for us, then? A vague idea for how much a crouched position helps with efficiency would be interesting. I have an intuitive sense that it's helping me out with highway mileage but I haven't been able to quantify that yet.

[hinse]

Hi,
I just installed an MRA wind screen: MRA.SPS.1
$99.99 from a nearby dealer in Ontario.
I immediately noticed lowered power use, today I took a long ride and got 50km with 4 bars left.
And my top speed easily reaches 105kmh,
Before I had trouble trying to get 40km and 97kmh before.

Best accessory to put on a bike by my judgment.

Pierre