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Hey everyone on the Diyelectriccar forum!
We are team EMUS (Electric Motorcycle of Universite de Sherbrooke), a team of mechanical, electrical and computer engineering students from Sherbrooke, Quebec in Canada!

We are currently launching a Kickstarter crowdfunding campaign to complete the purchase of our battery pack. Needless to say that the battery is one of the key elements of any electric vehicle and
by far the most costly. Any help will be much appreciated!

Kickstarter: https://www.kickstarter.com/projects/teamemus/emus-electric-motorcycle-universite-de-sherbrooke
Website: www.emus.ca
Facebook: www.facebook.com/Projetemus

As the title suggests, this article will be an overview of the build process of our all-electric motorbike to compete at the eMotoRacing Varsity Challenge this summer (July 11-12, 2015). To start this post on a good note, here are some mouth-watering pics of the bike as it sits right now!







Before getting into technical details, here are the major rules we had to consider while designing the prototype:
- Zero emission vehicle (indeed)
- Battery pack voltage below 680 volts
- Max. 35” overall width and 100” overall length
- Max. weight of 220 Kg.
- High voltage wiring adequately insulated and crash resistant
For a more exhaustive listing, see the competition’s rules page here: http://emotoracing.com/rules
The bike was first intended to race at FIM eRoadRacing, but it hasn’t announced any event for 2015 yet. However, eMotoRacing Varsity challenge is perfect fit for our team.

Since we wanted to have a significant chance to win the eMotoRacing Varsity challenge, we decided to start from scratch as most successful electric vehicle manufacturers did (Tesla, Brammo, BMW, etc). It goes without saying that this approach gives us many advantages in comparison to simply converting an existing vehicle. It allows us to:

- Design a bigger battery compartment
- Position the motor and powertrain as we need
- Use the lightest materials available for chassis and body panels
- Use the structural strength of the battery pack as part of the chassis
- Have more control on the fitment of every part
- Achieve a good weight balancing of the bike

On the downside, this is a far more expensive way of designing an electric vehicle and also more mechanically complex. To facilitate the design and to provide the driver a familiar driving experience, we used about the same dimensions as a 600cc racing bike. After many iterations on both electrical and mechanical systems, the project is now almost in its final form, but still far from ready for the eMotoRacing Varsity Challenge! The following section will briefly cover different technical aspects of our prototype. Don’t hesitate to ask any questions, we will try our best to answer!
General specs:

- Continuous power: 90 KW / 120 HP
- Continuous torque: 190 Nm / 140 ft-lb
- Peak power: 160 KW / 214 HP
- Peak torque: 450 Nm / 330 ft-lb
- Batteries: Li-Po, 12 KW/h
- Wheelbase: 1420 mm
- Weight: 220 Kg / 485 lbs

Chassis



As mentioned earlier, designing the vehicle from a blank sheet of paper allowed us to take advantage of the battery by using it as the central part of the chassis. The Lipo pack is housed inside a full aluminum monocoque chassis.

The swing arm, front fork, motor and basically every major component connects directly to the chassis. Using a monocoque chassis provides the vehicle better stiffness, protects the batteries and allows the use of a large rectangular battery pack. However, accessing or removing the batteries can be arduous.





Brakes

As most sport bikes, our motorcycle uses double hydraulic disc brakes on the front wheel and single disc on the rear wheel. Regenerative braking is also possible with our motor-controller combo.

The amount and smoothness of regen braking can be programmed and adjusted via the clutch lever to suit the needs of the driver.

Battery pack



The 12KWh 600 volts battery can put out 1000 amps peak current and is designed for a 45 kilometers racing range. The pack consists of three 600 volts main modules mounted side-by-side inside the

chassis, slightly spaced apart with air ducts integrated in the aluminum panels to provide natural air cooling to the battery.
These modules contain three 200v smaller modules connected in series, with their own BMS. A main BMS board processes the raw data sent by the 9 individual BMS then sends necessary information to

the ECU. Each 200 volts module is made of Turnigy A-SPEC RC Lipo battery packs. This type of batteries offers great power density (7.5 KW/Kg), strong charge and discharge current (65C discharge, 8C charge) and convenient packaging.



These cells were chosen amongst hundreds to fit our specific needs. The form factor, the weight, the specific energy, specific power and voltage were the main parameters we looked at. The fact that it also come prepackaged with bullet connectors was a great advantage regarding the assembly process and packaging.
However these cells come at a very high price of about 60$ per unit. Considering the battery pack houses 243 of these, it brings the price of the battery pack to 15 000$, cells alone.
 

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Discussion Starter #2
The main BMS controller and BMS modules are designed specifically for this application by our electrical team.




Motor and drive

Since the motor would be used in a racing motorcycle, it needed to meet particular requirements like high power density, shallow form, high speed and high efficiency. We used the Emrax 268 motor by ENSTROJ for the following reasons:
- High power in a small package (200 peak HP, 20.3Kg)
- 5000 RPM peak RPM
- High torque
- Liquid cooling capability
- 93-98% maximum efficiency
The motor you see on the picture is the Emrax 228 which we used for testing purposes. We will place an order for the Emrax 268 in the coming weeks.


The Emrax motor is synchronous 3-phase AC axial flux motor, with the highest power to weight ratio in the world. Like all permanent magnet AC motors (PMAC) it can be used as a motor or a generator (for regenerative braking).
A broad market investigation was lead to search for all commercially available products. Motors like TM4, Yasa, Agni, Remy or UQM were considered. Because of its small size, power to weight ratio and assembly method, it was determined that it was the beast suited for the concept. This outrunner motor is both aircooled and water cooled.

We adopted the PM150 motor controller by Rinehart Motion Systems to exploit the full power this motor makes. It features great power density due to its packaging and water cooling system. This motor drive has an incredibly customizable motor control software that permits current timing and control in the three phases to fine-tune the power response and efficiency of the motor. It also features standard CAN bus and RS-232 interfaces for control and debugging. To give you an idea of how good this controller is, it is used in all Brammo electric motorcycles!



We also looked at other drives like SEVCON, Bamocar, Unitek,Piktronik,TM4 but the RMS was the only one that could fit underneath the motorcycle without being too wide. It offers other advantages like being watercooled and allowing regen braking.
RMS are very supportive and offer great sutumer support. The drive is easy to program and understand.



Electrical system



Like most modern vehicles, data exchange between every electronic module is done via CAN busses. It connects our ECU with the main BMS unit, the motor controller, the front and back sensor data acquisition units and the front Kantrak 3700 display.


Like our BMS, the ECU is custom made for this vehicle. Both are based on the same STM32F105 automotive grade 32 bits ARM microcontrollers.

The end
Thank you for your interest in our project, we hope you liked this short overview of the EMUS motorcycle! Again if you have any questions, just post them in the comments and we’ll do our best to respond!
If you would like to support the project by donating to our kick starter project please visit: https://www.kickstarter.com/projects/teamemus/emus-electric-motorcycle-universite-de-sherbrooke
We are also looking for bigger sponsors.

PS: For “montrealers” reading this (if any!), project EMUS will have a booth at the 2015 Motorcycle Show in Montreal in two weeks (feb. 27-28 and march 1st)!
 

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Looks absolutely magic!
Please keep us informed
I am especially interested in your experience with those batteries
 

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+1 Duncan cant wait to see it run.
I downloaded the stp 3D file of the 268 to look inside it and yep it was hollow.
Brammos use Sevcons and definitely post results of the Turnigy packs.
good luck.
I think you will find your can bus everything concept will let the bike down when you get to track testing.
Too complicated.
And the primary chain will run very hot at those power ratings, it does twice the work as the secondary chain because its doing twice the bends per link per rpm. Make sure you have a top of range RK GXW

http://www.google.com.au/imgres?img...xVKu4MYONmwX5vIGICQ&tbm=isch&ved=0CB8QMygDMAM
 

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Discussion Starter #5
Brammos use Sevcons and definitely post results of the Turnigy packs.
good luck.
Hi,
sorry for the error, we will edit the post! I think Brammo uses RMS controllers for development or racing project but Sevcons in their production bikes? Some articles seem to say that!

"Brammo uses an inverter from Rinehart Motion Systems [...]"
http://www.mechatronictips.com/2013/08/2982/technology/motioncontrol/electric-designs-go-for-a-win/

"Brian at Brammo has been testing a new bike with a PM100DXR controller."
https://www.facebook.com/RinehartMotionSystems
 

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Hi,
sorry for the error, we will edit the post! I think Brammo uses RMS controllers for development or racing project but Sevcons in their production bikes? Some articles seem to say that!

"Brammo uses an inverter from Rinehart Motion Systems [...]"
http://www.mechatronictips.com/2013/08/2982/technology/motioncontrol/electric-designs-go-for-a-win/

"Brian at Brammo has been testing a new bike with a PM100DXR controller."
https://www.facebook.com/RinehartMotionSystems

Yup If I was Brammo Id be looking at RMS too .
Ive arrived at the same controller (PM100DXR) for my next bike.
180hp and a manageable 395v (94s LiPo)
Even planned changing the aluminium casing for an Acetal one with copper heat sinks because 7kg is just too heavy !
 

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Yeah, RMS PM100DXR's for the racebikes (the RR's) and Sevcon Gen4 Size6 for the production bikes.
 

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You will enjoy this YouTube onboard video of Voltron Evo.
The 700v beasty from Perth that has the same PM150 that you have.
The PM150 will give you that extra 20hp over the PM100DXR that will make the bike a bit harder to ride (wheelspin and wheelies) and make you realise that the extra 3kg wasn't worth it.
Going for the lighter less powerful controller is worth more on track in terms of lap times.
Racers hate wheelies !
https://www.youtube.com/watch?v=rUQNGq6NPTI
 

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Discussion Starter #12
Awesome bike , congrats!

Hobby king batteries have a high failure rate (10%), how do you guys work that out?
We setup a bench test with Turnigy ACCUCELL-6 balance chargers/dischargers. Each HobbyKing pouch is tested for residual capacity before going into the main packs!

 

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Kudos to everyone!
______________________________________________________

That is a well planned and executed machine.

Now, if I might portray the prophet of doom? Everything looks top notch except for one thing. (And you may have already tossed this around the group.) The chain span looks to be too long for the pitch you are using..... my guess is it will pick up a harmonic vibration as you accelerate through a certain RPM range.

I have had this happen on odd occasions.

Just keep it in mind when you get it in the track testing stage.

Miz
 
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