Help with a solar car race competition!

[jasper1122]

This is my first day here, I'm not sure if this is the right topic.. haha anyway

I'm a year 10 student from Australia and have been chosen by my school to participate in the MSV Victorian Model Solar Vehicle Challenge.
If I come up with a convincing design and strategy, I'm gonna be funded $500 to spend, I'm really desperate for any help I can get,

If anyone wants to help out it'll be greatly appreciated
here's a link to the regulations

http://www.modelsolar.org.au/Build/DESIGN%20OVERVIEW%202013%20MODEL%20SOLAR%20CAR%20low%20resolution.pdf

Please please please help me out, specially with the last part..

"The winning car was of excellent build quality but included a feature which by my computer simulation offers a possible 0.9 second advantage. This feature consisted of a mechanical switch that was activated by distance travelled to change the panel configuration from parallel to series. Being mechanical this is perfectly legal and qualifies the car for non electronics ballasting. While not a totally new concept, it was mentioned in a publication around about the mid 90’s but no one has incorporated it in a car before now, at least to my knowledge."

Does anyone know how to do that?

I also know a great deal about Faulhaber and Maxon motors, please somone help me out
If I get enough people interested in helping me, I'll update with pictures and upload my research and everything.

Have a good one ;P

[robinnes]

You could use a simple spdt relay.
higher batt voltage holds it closed (in parallel mode) once batt voltage drops below a pre-defined mark- the relay releases and swithces to series circuit for "after-burner" mode!

[Sunking]

$500? That will not even buy a motor.

[SunEagle]

$500? That will not even buy a motor.

Those cars have a 900 gram weight limitation and designed to hold a raw egg.

[jasper1122]

You could use a simple spdt relay.
higher batt voltage holds it closed (in parallel mode) once batt voltage drops below a pre-defined mark- the relay releases and swithces to series circuit for "after-burner" mode!

Hey robines!

from the regulations it says:
"Energy storage: not allowed, except capacitors up to 0.2 farad provided they are discharged immediately prior to race starting. Inductors up to 1 mH allowed."

No batteries allowed bro
power will come either directly from the solar panel into the motor or through first electronics - and then the motor.

Right now, my understanding of capacitors and inductors are that they're "like" batteries since it's under energy storage..?

I kinda found out how to switch from paralel to series by the use of a speed speed sensor.
and a circuit like this.. http://www.solarfreaks.com/download/file.php?id=439

[jasper1122]

Those cars have a 900 gram weight limitation and designed to hold a raw egg.

thanks for that Suneagle, have a look at these winner cars from previous competitions

http://www.modelsolar.org.au/Galleries/ModelSolarCars/Winners2011

I believe the regulations have changed though, It's a milk bottle now

"CARGO SPACE:
An enclosed space behind the driver and beneath the Solar Panel large enough to hold1 standard 2 litre plastic fresh Milk bottle. (Any orientation is allowed.) The floor must be capable of supporting the full 2 litre plasticmilk bottle standing vertically anywhere on your designated cargo area and the car capable of rolling without the panel attached. Only ballast is allowed to be in this designated space."

cheers

[Sgtdic]

Good luck! The only thing I can mention is relating to capacitors. Think of them like buffers, or a sponge under a water faucet. They take it in but will slowly discharge all the water. Of course there are different specs for these as well. They will hold power but only temporarily.

[jasper1122]

Good luck! The only thing I can mention is relating to capacitors. Think of them like buffers, or a sponge under a water faucet. They take it in but will slowly discharge all the water. Of course there are different specs for these as well. They will hold power but only temporarily.

Thanks mate! Will try to put that info to good use

[jasper1122]

$500? That will not even buy a motor.

Oh yeah, dude the motor I'm looking at is a $165 Faulhaber 2232 6V motor. That's what most cars, and the winning cars had.
here are results from a past competition

http://modelsolar.org.au/Results/CarData2011VMSVC.pdf

Although this guy from this thread in http://www.solarfreaks.com/faulhaber-vs-maxon-t8.html said
"Ian Gardner from Victoria has just finished testing of the Maxon RE25 118740, and he just confirmed it is currently the best available motor for solar car. Current estimates are a 0.5 - 1.5 second decrease in lap times. The motor provides up to 80% more torque per RPM compared to the faulhaber 2232. Although it weighs 75grams more, he stated the benefits easily compensate for the extra weight and more."

The Maxon RE25 118740 costs roughly $265 ... now I've compared these two myself by looking at it's statistics,
the faulhaber is faster with more rpms but the maxon has more torque. I'm really not sure what has a better advantage and even more so on which one to get; the faulhaber has had more experience on the field while i've never heard anyone use a "Maxon RE25 118740" - and win. Maybe it's because no one's prepared to spend an extra $100 or so in a motor? or maybe because the faulhaber actually is the best one? I have no idea.

I need to get more opinions on this before looking into getting the more expensive maxon - I can't just trust "Ian Gardner"; you know?
If it is better though; there will be no holding back.

[SunEagle]

thanks for that Suneagle, have a look at these winner cars from previous competitions

http://www.modelsolar.org.au/Galleries/ModelSolarCars/Winners2011

I believe the regulations have changed though, It's a milk bottle now

"CARGO SPACE:
An enclosed space behind the driver and beneath the Solar Panel large enough to hold1 standard 2 litre plastic fresh Milk bottle. (Any orientation is allowed.) The floor must be capable of supporting the full 2 litre plasticmilk bottle standing vertically anywhere on your designated cargo area and the car capable of rolling without the panel attached. Only ballast is allowed to be in this designated space."

cheers

I like that 3 wheeler design which took 1st place. Pretty cool. Good luck with your entry.

[axis11]

drive wheel

Try to apply the driving torque in the centerline of the car. The example picture you've shown has only one drive wheel and it is not centered. It will create torque steer and increase frictional resistance on the guides. You could either go for a three-wheeled design and have the center wheel be driven or a 4 wheel design that has both wheels on the same axle be applied equal torque.