2012 eV Challenge Perth Teams

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Coulomb Racing
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Post by Coulomb Racing »

Hi Everyone,

Met a few people at the Perth electrikhana and wanted to know if any teams other than the River Raiders have active blogs, Facebook pages or tumblr feeds to follow.

My construction of this years entry can be found at;

http://www.facebook.com/pages/Coulomb-R ... 8400779816

and;

http://coulombracingtechnologies.blogspot.com.au/

Hope to see more people getting interactive with the online community and showing how much effort goes into building the vehicles.

James    
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Crash
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Post by Crash »

How are your 2012 cars going? The race is on next weekend at the RAC Driver training centre.

This is one of a handful of races for battery electric cars and it seems to be the only electrathon style event in Australia. There is a wide array of locally built cars from schools, tafe, colleges and private entrants.

The racing is unpredictable - as the end of the race looms and batteries start to fade, positions can change quickly.

Come a show your support for an event that makes it fun and affordable to build and race your own EV.
Canberra32
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Post by Canberra32 »

As I'm keen as beans to enter next years race here is a question. Or two.

What is the average speed of the cars?
Dose it count if one sacrifices laps for more fun and speed if you get your 30 or so laps done but burn out in 30min?
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Adverse Effects
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Post by Adverse Effects »

Canberra32 wrote: As I'm keen as beans to enter next years race here is a question. Or two.

What is the average speed of the cars?
Dose it count if one sacrifices laps for more fun and speed if you get your 30 or so laps done but burn out in 30min?


speed = wast

more speed = more wast

as it is i am guessing that the power packs will be only just a bit bigger than needed to do the race so you want have much at all to wast
Canberra32
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Post by Canberra32 »

Yeah wast. But if it still dose a decent number of laps then ok.
Not using human or sun power is a wast...
There is a point where I think I need a trade off for some speed.

If you told me you had a car that did 5000km on a single charge but did it at 5kph I would say keep it :)

Example.
Time is not the object of traveling a distance.
If I did 30 laps in 30min while another car did 30 in an hour on half as much battery in theory I would have been charged and ready to go again before they finished...
So where do I put my trade off in real life?
A less battery friendly car and less wasted time and quicker to get on charge verse a slug with range?
I get payed by the hour so I have to go with the life is short dont wast it either!
The sun provided me with my power and all is well I say.

For the EV challenge I want a rig that reflects my real life. A modest amount of laps but by no means a dud run but leaving behind me a eatable trail of exhaust free dust :)
My aim is to come up with an edgey design that looks good goes well and is comfortable.
A better goal than just range I think.

For those looking for a good structural option for EV challenge builds the other day I sawed two lengths of high density polystyrene foam 50x100 mill and used a cheap 12k carbon weave with one layer all round and almost dry epoxy kind of a RHS substitute and ended up with a 3m length I could put between sawhorses and sit on and bounce no problem at all :) it's not for my car but it was super light and way stronger than I thought.
Worked out at $23 a lineal meter :)
I would think a 35x50mm would also be quite strong though slightly more difficult to make and more flexy :)

Would anyone want to buy a 1000k range ultra ugly 50kph car for an epic amount of dollars? :) noooooo
Because if its about just saving the planet and emissions get on a push bike and use human power last I checked we don't run on oil :)
Greased or deep fried maybe but u get me :)

It's the same reason I went DC for my real car build :)
Range is not so bad with a 48 180ah cells and 700pounds of torque at the flywheel I could't care less about range :)
I just had to replace the diff center on my test frame as it ended up with no teeth :)
I won't be planning my driving trips worrying about are there hills :)
Canberra32
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Post by Canberra32 »

And yes good question adverse.
Are we able to have a slightly bigger pack than required so we don't have to thrash our batteries to death each run to great our 432wh ?

Anyone know?
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Crash
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Post by Crash »

Average speed of cars is about 40km/h. Fastest lap times of the 1 22 on a 960m track.

The battery packs are limited by the rules to 432 Wh. If you allowed them to be bigger we would still run them to the limit. Get a good battery management system and you can run them to the limit safely.

The idea of going twice the speed for half the time will be difficult because the maximum battery pack size is controlled by the rules and it is not very power at all, so is all about efficiency.
Aerodynamic drag is proportional to velocity squared so you will use four times the power to go twice the speed in a straight line.
You will need a heavier motor, chassis, drive train to transmit four times the power, so will use more power accelerating and braking.
If you double the speed to average of 80km/h you will need to be going about 100km/h down the straight as you won't be able to go flat out around the bends. The EV Challenge cars use bicycle tyres which wont be suitable for these kind of speeds, partic around corners in a heavier car, so you would most likely need to go to motorbike tyres, so more drag and weight.

I wouldn't say that it isn't theoretically possible in a straight line because people have ridden an aero faired recumbent bike at over 100km/h, but I can't see you being competitive with this strategy.

And at the end of the day it wouldn't be safe weaving through the traffic at twice the speed - our car certainly isn't built to get hit from behind by someone doing 100km/h.

Canberra32
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Post by Canberra32 »

Lol yup get you :)
And yeah the bike wheels are just a death trap :)
Wheelchair race wheels are made for much higher speeds and loads with very little drag.
Spokes don't take side load so unless you lean over on the car at the change in inertia machine up some mags on the lath :)

I'm by no means a fool when it comes to design so I very much doubt my car would be deemed unsafe.
There is also more to aerodynamic drag than just the shape of the car ;)
Canberra32
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Post by Canberra32 »

Also on the smacked into from behind note may I ask all of you WHY the cars are not built for a crash?
Do we all not remember as kids the crashes on bikes?
Is there not some standard safety issues to address ?
I plan on a 300mm thick block of foam front and back personally :)
Are we setting a bad example for the children's ? " get away son daddy has to race his death trap its for the environment... Hold my beer"
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