EducEco-EcoMarathonShell

[louis4sun]

Hi
FYI:
In june 2009, I participated the EducEco challenge (Nogaro Grand-Prix circuit)
http://www.educeco.com
Category All-Electric Car (battery)
We (Paris X university IUT-VA) won in that category
Range to drive was 7 laps (25.272 km at minimum 30 km/h average speed)
Our e-Car spent total 132646 joules, that corresponds to 1.458 Wh per km
It is a e-trike + aerodynamics light body
Motor was a BLDC Dualsky XM6360-CA12 Kv 220 rpm/V 618g
(source = motorbike batteries 24V)
Geared by chain : motor pinion 11 teeth, wheel sprocket 129 teeth
We mounted a centrifugal-chuck for a good starting
I was in charge of motor+controller+battery
We plan to participate in 2010 and to improve our record (objective is 1.2 Wh per km)
Louis

 

[John in CR]

Louis,

Congrats on winning. 1.5wh/km is great. Was there human assist, or is that just pure EV?

Some day soon an entity with sufficient capital will wake up and realize that the 2 ton behemoths with poor aerodynamics (ie cars of the past 100 years) are a thing of the past, and those leading the way like yourselves will have input or influence on the vehicles of tomorrow.

Best wishes on your attempt to get below 1.2wh/km. Any of your group have designs to share that include multiple passengers, while staying below 20wh/km and maintaining traffic speeds?

John

 

[spinningmagnets]

Here's a quick low-res pic

 

[louis4sun]

Hi
EducEco challenge "all electric" is pure EV
Pedaling is forbidden, also wheels have to be protected against arms-hands action.
Another category is "solar + battery" (but nomore human energy)
Louis

 

[spinningmagnets]

Excellent work Louis!, so if the kV is 220, and the battery was 24V, the motor spins at 5,000-RPM? This sounds like some of the RC-motor builds in the "non-hub" section.

25-kph to 30-kph equals 15/18-MPH.

Louis, what is your design philosophy and advice for an e-bike to get better range?

 

[louis4sun]

Hi
Kv = 220 *24V * coef(for efficiency around 80%)
That is around 4200-4300 rpm at full throttle
Wheel-tyre rolling diameter is 500 mm (Michelin tyres)
The pilot ( young girl student < 50kg ) is alternating
motor-ON-time .... freewheel ....ON .... freewheel
Louis

 

[louis4sun]

Louis, what is your design philosophy and advice for an e-bike to get better range?

Hi
It is difficult to me to give an advice.
For a recumbent e-Trike, I have a good opinion "a priori" on
a) A hybrid serie (pedaling to a generator + battery + BLDC motor outrunner + chain but low Kv in the range 50-100 rpm/V to avoid great spurs like 120teeth
and small pinions as 11t)
b) Reduction about ..-20-.. /72 is better, possibly a "derailleur" to change 16-18-20-22-24 motor pinions, 5 speeds
c) ESC with sensors to have a good starting torque
d) Solar roof on a trike to help getting electrons during outdoor stops

Louis

 

[spinningmagnets]

"..The pilot is alternating motor, ON .... freewheel ....ON .... freewheel..."

At a hypermiling website this is called "sprint and glide" and it works with gasoline engines too.

The aero-civic website was very interesting. When he would drive at freeway speeds in the stock vehicle, as soon as stopped pushing the engine, the wind-resistance slowed the car rapidly. After installing various aero-improvements to the body, he would drive it to a certain speed. Then when he crossed a marked spot, he would stop accellerating and see how far he would glide. It was low-tech, but it provided quick and accurate results when trying various add-on shapes.

Making the vehicle lighter helped the most in stop-and-go city driving, but the aero-improvements made a very big improvement at highway speeds. Using "sprint and glide" with a stock shape of car was trouble-some. But in a slick body, the aero-cars would glide a long ways before needing to add power to maintain speed.

 

[John in CR]

Shouldn't it be possible to use 2 motors to avoid sprint and glide with near the same efficiency? ie one motor to accelerate and a smaller one to maintain the "glide"?

John

 

[louis4sun]

Shouldn't it be possible to use 2 motors to avoid sprint and glide with near the same efficiency? ie one motor to accelerate and a smaller one to maintain the "glide"?

John

Hi
Certainly Yes
Louis

 

[spinningmagnets]

I haven't converted an E-motorcycle yet, but I am a fan of the 2-motor method. I want a rear hub-motor and perhaps an Agni with a chain. Maybe a few years from now, just scribbling on paper right now...

 

[louis4sun]

I haven't converted an E-motorcycle yet, but I am a fan of the 2-motor method. I want a rear hub-motor and perhaps an Agni with a chain. Maybe a few years from now, just scribbling on paper right now...

Hi
Personnally I would prefer an outrunner BLDC + sensored ESC system to get torque at zero speed.
AGNI motors are brushed, some of my friends burnt several times brushes.
Louis

 

[spinningmagnets]

I think the easiest and most "do-able" 2-motor configuration is a hub-motor plus a cylindrical motor+chain. Since the hub spins at wheel RPM's, I'm assuming it must be much less efficient than the high-RPM cylindrical motor, so the hub would only be used during accelleration, and the other motor would be used all the time.

What is the largest BLDC outrunner available? What power would be needed to maintain cruise speed at 60-MPH? My thought to use the Agni was just because its smaller and easier to fit than the ETEK. It would be a couple years in the future if I do it at all...

 

[louis4sun]

Hi SpinningMag

If you project a trike delta
Front wheel could be steered
One chinese hub motor on one rear (BionX, Crystalite style as examples), possibly complete wheel.
One non hub + chain, the other side
There are some medium power outrunners (around 8-10 kW)
** Yuneec motor (sensored)
** Eck-Geiger motor combo
** Free-Air
** Flyware BigRex1240
** Plettenberg Predator
** for memory, avoid RS-Motoren (not so honest)
For myself I am working on that size system (sensored), but I am not ready now. Maybe 2010.
It depends if
A) You don't want acceleration
Low power (600W) BionX could launch the trike
B) After running you start the second motor (high power sensorless) to get speed

Or you make the contrary
A) High power sensored to accelerate/start
B) Low power to "glide" (could be sensorless)

Note
At EducEco-EcoMarathon we "rise the speed and glide".
During "sprint phases" the peak power was around only 550W to reach 39 km/h
Louis

 

[spinningmagnets]

Thanks for your suggestions, Louis. As I said, it may be a few years, but I am very interested in an E-moto conversion. I will keep track of new developments and products that will help such a project.

 

[monster]

1.5 wh/mile is amazing!

you could put solar panels on that and it would not need battereis?

 

[louis4sun]

Hi
Not per mile, only per km
Louis