Solar Freaks

This Topic has been split from this thread: solar-karo-t330.html
TonyB

hi miseli,

i have to agree that running with electronics seems to more evenly match the competiveness of most cars irrespective of the build quality and thought put into designs these days. today just about anyone can pretty much throw a car together and complete respectiable times around the track in most light conditions.

the current 30% weight addition for running electronics most definatly needs to be increased for most teams even to consider running without electronics as it can be seen that most teams these days are so relient on them they would not no what to do without them. (in terms of gearing for different light conditions, various motor possibilities, panel arrangements [series/parallel] etc)

from the years 2003 to 2007 i competed at both state and national level each year in times when electronics were not used and relied upon as much as in todays current frame of mind of students and teams. in this time we did not use electronics until nationals 2006 when it seemed to be a neccesity in order to compete with the rules at hand. the years before this i believe through efective car design much more was learent with concerns to the actual workings of a model solar car. rather then just designing a car with one set up that would perform under all light conditions and was not able to be adjusted for varrying conditions.

"back in the day", our team had a variety of motors avaliable (maxon and faulhaber) which needed to be tested in order to determine which motor was to be used in particular light conditions. this also complemented with the use of a variety of approx 30 different pinion and 3 spur gears along with 2 different pitches of gears. furthermore as you stated our panels were wired with 3 switches allowing the panels to be changed from varietys of series and parallel.

if the rules were to change (hopefully in recent years to come) i believe that students would be able to gain much more knowledge about the workings of the own cars and model solar car design in general. having to consider gears, panel settings and motor possibilities (along with designing an effeective car to comply with the rules) before each particular race rather then turning up with a 'one setting car'. this would hence be able to through out the dominance of cars running electronics and have been for many years relying on them to make them competitive and create a competition that is much more open and widespread.

viper01

Hello Viper01,

Yes, I agree that probably few students these days would know what to do if faced with an electronics ban. I can't ever see this happening though. A further weight reduction for no electronics maybe, but not a ban. Almost everything in the real world uses electronics these days.

As you say, just about any car will do alright with electronics. If everyone uses electronics though, the playing field is then leveled out and the inferior cars will still be beaten by the better ones. It just means that the slower cars will still turn out half decent lap times instead of performing poorly or even failing to complete a race.
Being able to build a car that does reasonably well will keep students and schools happy and keen to improve and return in future years.

Going without electronics can be tough. Particularly for schools new to the challenge. Firstly, someone needs to have an idea of what's going on, and secondly, the finances and facilities need to be there.
As you have pointed out, when you were racing you had a vast selection of gearing to choose from. This does however bring an additional cost to the challenge which, at times, is something schools can't afford.
I neglected to mention the possibility of a change of motor in my earlier post for this same reason. Gears may be one thing, but to purchase a variety of motors to give oneself a selection to choose from would be out of the question for all but a minority.
Having a test track at hand is also something that very few schools have the luxury of accessing for testing. Turning up on race day and sticking a no-electronics car down on the track for the first time without running a single test is not ideal preparation.

I competed from 2003 through to 2006 and the team played around with going with and without electronics in the first year or so and was familiar with both. It was soon discovered that with the rules at that time and a decent electronics unit, there was no real contest. With limited school funds, it was also the most viable option. Even with the electronics, a number of gear ratios and several wheel sizes were still made available, but were rarely called upon.
The school finished 1st and 3rd at the nationals in Melbourne in 2005 and then 1st again in 2006 in Sydney.

I agree that students would gain more knowledge investigating no-electronics. The knowledge on certain areas does appear to be lacking a little at the moment. I think the committee has made a step in the right direction this year and will again be campaigning to further this in 2011. The reduction figure could possibly increase to 40% or maybe even 50% next year.

Ideally, I'd like to see a sizable advantage given to no-electronics cars (even in good sunlight). That way, students willing to take up the challenge and take the risk will be rewarded if they get it right. Get it wrong and the electronics car will win. Seems fair to me.
I'll be surprised if anyone can pull it off at the nationals this year under some pressure.

miseli

miseli,

true. i would have to agree that a total ban of electronics in todays competition would not be an option. as you say many various fields and about everything uses them in todays society. though the reliance upon them needs to be reduced in future years of competition.

as you say the competitive edge needs to be given to a car that does not have the use of electronics in perfect conditions as they are difficult to come by. any possible edge regarding a car not running electronics needs to be given just to give them a slight possibility of winning the race in some cases. the reward may come though get it slightly wrong without the use of electronics and you have no chance in the end, especially with varrying and low light conditions changing throughout thhe course of a race. the 40%-50% weight increase as you sugested seems to be a good possibility in order to cut the advantage that cars running electronics have in todays competition.

the simplicity of runnig electronics in some cases as you mentioned compared to not (smaller variety of gears etc) would dramatically reduce the cost of competing allowing for more teams to compete and continue to come back each year with newly developed cars. though i still believe that so much more can be learnt by students from running without the use of electronics, even though in most cases they will not be as competitive in todays competition.

i pose you this question though what can be seen to be more important in todays competition winning or the development of knowlwdge and understanding of solar energy ??? the line seems to be blured to which is more important in some cases; though in the end it is a competition.

viper01

Viper01

Why do we use electronics in solar cars? and in life in general? The whole point is to make things easier.

Every solar system, weather it's a Grid connected residential solar system, or an off-grid solar bore pump, or even a solar powered satellite orbiting the earth uses a maximum power point tracker. Why? because to optimally harvest the power from your solar panels, they need to operate at the Maximum Power Point.

If the idea is to teach and familiarize students with solar electricity, then i think electronics units will familiarize them with the characteristics of a solar panel. Any enthusiastic student will ask themselves... Why do i need one these electronics units?? And in that question, they will learn of how a solar panel operates and its characteristics.

When i raced in years 2000 - 2003, i knew i had to operate the panel at the MPP. But it was just too fiddly, and as Marc said, without testing, its impossible to find the right combination. I knew it had to be done with gearing, motors, series parallel etc etc. There was too much mucking around for the 1 or so hour of test time you have, and if the weather changed the day after, bang, your gone.

I dont think most students take electronics for granted. Most students ive seen appreciate the technology, and try to understand why they need one.

Without electronics, the schools that have years of experience in the competition would be extremely advantaged, any new schools, with limited funding/resources would have a slim chance.

TonyB

TonyB,

as you said electronics and MMP's are obviously used to advantage us in our everyday lives. this hence has been transfered to the solar car competition posing great advantages to teams who choose or can afford to use them.

as long as teams focus on the core components of car design and development they will hopefully also learn of how a solar panel operates and its characteristics with the use of a maximiser. as long as they know and understand why it is advantageous to be using electronics compared to older methods which as you said can be very fiddly and time comsuming though satifying in the end also if you do on the off chance get the optimum set up.

ps. hows the automax going lol ??? ben smashing them out with u haha...

viper01

Viper01,

First you bemoan the use of electronics, then ask Tony how his Automax is progressing!!! Make up your mind!

Tony and Marc are correct. Electronics are here to stay. There is just as much to learn about solar panel behaviour with a maximiser as without. I doubt that many students really understand why they have to change gears without a maximiser, they just rely on the experience of previous years. As Marc said, a new school entering for the first time with no real idea of what they are doing will get instantly depressed and probably never come back if their dream car won't make it around the track. Put in the most basic of maximisers and the car does laps. It won't win but at least it goes so they will more than likely come back again next year. Maximisers don't make bad cars good, they make good cars better and that is the whole point of the competition, to do better. You still have to start with a well built car, and that is where most teams fall down, maximiser or not.

The cost? Maximisers cost less than a second motor which is why we went that way back in the late '90s. Well funded private schools had multiple motors and a selection of gears but not many other teams have this option so they take a different tack.

Getting back to whether maximisers are educational or not, I wish you could see the inverter on my rooftop installation. This morning, in the cold and shade, it was producing 269V but no output power. Then it was producing a whole 3 watts at 220V. Later in the day it was turning out 590 watts at 209V. The best I have seen on a hot summers day was 1050 watts and this was at only 179V. The inverter runs a maximum power point tracker as required to enable me to get the government grant, so it would be eye opening for anyone who does not understand solar cell behaviour to see how the maximum power voltage varies, not so much with the light level, but with panel temperature. Good luck getting that right on your solar car just by changing gears.

Perhaps there is an argument for banning automatic trackers, but I don't see why. Let's all go back to the stone age and be done with it.

I'll bet not many of the students, or teachers for that matter, can explain satisfactorily even the basic behaviour of a solar panel. Same with motors. Why do we allow these inside out precision motors? Why do we allow rare earth magnets and precious metal brushes? For that matter, how about penalising teams that use carbon fibre? Ball bearings, moulded gears, even heatshrink tubing? Where do we stop? It was all revolutionary technology once upon a time.

john,

my argument was to never ban the use of electronics, maximisers and/or auto trackers completely that would be unrealistic, though to more evenly match cars that choose to run with or without electrionic and bridge the general advantage that cars running these components have over the other. realisticly a car not running electroinic would undoubtly have no real chance against a car of the same build quality not running any electronics correct? unless the correct set up for the particular conditions of the race can be achieved by the car not running electronics they may have some chance.

adjusting the rules to faviour a car that does not run a maximiser to maybe 40% or 50% rather then the current 30% could even out the competition and allow cars to be more evenly matched weather they decide to run with out without a maximiser. realisticly with the current rules teams dont really have a choice as running without a maximiser and with the current 30% weight rule, they would have no chance.

i dont think that new schools entering for the first time would get instantly depressed and probably never come back if their car doesnt go as well as had been expected. im sure teams have realistic expectations having never competed before and will learn from their mistakes and gain valuable ideas from looking at other cars and still come back to improve upon their designs in future years with the use of a maximiser or not.

Hello Viper01,

With the current 30% reduction of required panel weight for no electronics, there is in fact already an advantage there. Well, this is what simulations are showing anyway.

Problem is that this is dependent on the weather.
In good sunlight, cars using electronics have the advantage. Period.
In the lower sunlights, however, the cars without electronics should win if perfectly set up (by a second or two depending on the conditions) and if simulations are anything to go by.
The sun level at which there is a cross over has not been determined (it would be a little vague anyway) and been left to teams to discover.

This is why the current regulations allow teams to decide to go either with or without electronics before every race.

Now, there are a couple of reasons why making use of the no electronics advantage that is there is going to be difficult.
Firstly, as has been discussed in the previous few posts, getting the correct setup is not the easiest thing to do. If you're a little off, the advantage will immediately turn into a disadvantage.
And secondly, even if the correct setup is used, nothing is stopping the sun level from changing just before or during a race. It must be remembered that overcast conditions (where the advantage is at) tend to mean that there will be more sun intensity fluctuation than when it is a clear and sunny day.
Since the nationals are over in WA this year, where the weather is impeccable 99% of the time, I doubt we'll even see a car considering no electronics. State events in the east may see something different but I doubt it. I hope I am proven wrong.

It is because of this difficulty to get things right that I would like to maybe see the weight reduction be increased by just a little more next year. This would shift the cross-over point to a higher sun level (or even eliminate it) and increase the advantage in lower sunlights (and chances of winning) for a no-electronics car.

I guess we'll see how things turn out this year and then go from there.

miseli

Viper01,

Getting the 'correct set up for the car' without electronics is virtually impossible.

Using a maximiser the car will (hopefully) operate for the whole race at the maximum power available from the light falling on the panel at any one time. This will vary with light level, angle of incidence, panel temperature, etc. The motor torque will vary depending on the speed of the car, because it is proportional to the motor current. This current will at least be equal to, or for most of the time, far exceed, the panel current.

Without a maximiser the car will operate at (almost) constant torque for the whole race, the power will vary wildly. Why? Because a solar cell produces current (almost) directly proportional to the light falling on it. This current is (almost) converted directly to output torque. The light incident on the panel will vary during the race simply because even under a 'clear' sky the level of radiation varies constantly. Toss in a few clouds or even just some humidity and you're in trouble. Add in the angle of incidence. Few tracks are dead level and also change angle over the lap. Did I mention the hill? Up and down. What was the orientation of the track? North south? East west? Something in between? What about the loads on the car? Assume a perfect car. Toss in some wind. Wind resistance follows a square law. What is the wind direction? Across the track or along the hill? Is it constant? Gets tricky, doesn't it? All these varying loads affect the speed of the car, therefore the speed of the motor, therefore the motor and panel voltage. This slightly alters the panel current as well, which then further complicates the whole issue.

Someone please show me the high school students (or the teachers) that can analyse this (and there is even more) before each race and make a rational decision. Of course they can't, and neither can any simulator, which is why an attempt has been made to offer teams the choice to see if there is any real interest. No-one knows what the actual advantage may be, or even if it is the same for all panel powers and car weights.

The only safe way would be to have two separate race divisions, for cars with and without electronics. And then we could have a division for cars with 4 fixed wheels. And one for cars without rear guides. And one for teams that didn't bother to read all the rules. I think 32 separate divisions would make it much fairer for everyone.

miseli,

i agree totally with what you have said.

achieving the correct set up for a race let alone for one with varying conditions throughout without electronics would be an achievement in itself for teams in order for them to compete with cars running maximisers. simulations are one thing though on race day im sure results will vary with the proposed advantage that cars not running electronics actually have.

as you said there may be a slight advantage with the current 30% ruling according to simulations in particular constant light conditions though is this really enough for teams to seriously consider racing without electronics... given the choice before each race as teams are, i dont think we will see many if any teams this year bold enough to attempt running without electronics. the gap in performance generally is still too large. especially at nationals in WA as you mentioned.

hopefully in the years to come maybe we will see cars that are able to give cars running maximisers a run for there money but i dont no how likely that will be. though for a team that is able to, congratulations will defiantly be deserved.

viper01

I think the electronics discussion should be moved to a more appropriate place.

Poor Karo, the thread is bombarded by MPPT's and maximisers Vs no electronics.

In regards to electronics,

I just see it as another important component for the competition. It is always developing and has been to great significance with relation to solar energy and particularly in the recent years of competition. Every team last year did use it, and from a schools point of view, they might see it as the most cost effective alternative to increase the consistency of their performance, especially with new teams that lack in experience. I second Tony's point where "some students appreciate the technology, and try to understand why they need one" having electronics will only broaden the aspect of knowledge for a student.

I do see the argument for further reduction of ballast with no electronics, but i can only see experienced schools with an abundance of equipment (pinion gears/motors) and funding taking those rules on, and even then they might hesitate on the advantages in which the electronics carry especially on its convenience and consistency. A Further reduction is debatable, but the majority of schools will probably still favour electronics. A team who doesn't use electronic will probably feel pressure on using it due to the vast majority using it, as electronics provide a form of parity towards the competition. I would gracefully congratulate a team that does win without electronics, but that'll only happen in low sunlights and their efficiencies must be bang on.


P.S out of curiousity, when was the last school without electronics winning? 04?

Hello firefly,

I think you're right there.....this topic has really deviated from Karo's initial thread. Maybe Tony could move it to an electronics vs no electronics thread?

I too would like to follow Tony's thinking of "some students appreciate the technology, and try to understand why they need one" about electronics, but to me the "some" in that quote would in actual fact be "a few" or "very few". Yes, there are some that bother to take an interest but it appears that many tend to have very little idea. It might be different over in NSW, I don't know.

Yes, to answer your post script question, 2004 seems to have been the last year that a car without electronics won the event. That was also the last time a team from WA won the event.

John, Tony, correct me if I'm wrong, but I don't think that a team using electronics had actually won until Hobart College took out the crown in 2005. Up until then the WA teams with their gigantic budgets had dominated the event winning 10 of the past 12 national events. Since 2005 it has all been electronics.

miseli

Ha, its alright firefly and miseli, I like reading this stuff!

I have been running maximizers for the two years that i have been racing in the solar car competition. Personally, when I want to buy things like maximizers, motors, solar panels etc, I like to look at the stats. EG, for solar panels, how efficient is it, V, amps everything, but just knowing the stats isn’t really enough, so look and find out what it means for a panel to be 30% efficient. Is it better to be efficient if under high light and so research begins. Even though running electronics, my knowledge has only broadened simply because I want to learn. If people just shove things together, no research, they aren’t going to do well, even with electronics. Good cars come with time, practice and really, determination. I love the line John mentioned that ‘Maximisers don't make bad cars good, they make good cars better’. I think that this very true and I personally don’t highly agree with the extra penalties for having electronics. Everything depends on the weather and I believe that maximizers aren’t always going to win, there is a difference when running under high light and running under low light.

This is my opinion and I can tell you that 2-3 cars at my school have already decided not to go with electronics, and it doesn’t mean they are going to lose or not go well, they still have a 50-50 chance, it all depends on the weather.

Karo,

"I too would like to follow Tony's thinking of "some students appreciate the technology, and try to understand why they need one" about electronics, but to me the "some" in that quote would in actual fact be "a few" or "very few". Yes, there are some that bother to take an interest but it appears that many tend to have very little idea. It might be different over in NSW, I don't know."

You have a point there. There could be some lack of communication with the students in regards to the maximisers, some students don't ask or some students never get told. Either way, only keen students will know and it will only benefit them. The fact still remains although to a slightly lesser extent, building/design the car is still the most influencial aspect of the competition.

Marc,

On the subject of when was the first time a maximiser car won the nationals, you are right about some of the teams and their 'facilities'. Ewen came second in Sydney 2002 after winning 32 races in a row including the first 2 of the best of 5 finals against Christchurch WA. They called time out and then won the next 3 with a sudden amazing increase in performance before locking the car away out of further scrutiny. In those days the weight was worked out differently and they used bare cells that were ex NASA complete with fake invoices and paperwork, so they ran very light. When the details came out this panel was banned next year in WA, or so my impeccable source tells me. 2003 in Adelaide, Ewen was knocked out in the quarters by a certain NSW church school (name withheld to protect the guilty) that had a panel that recorded only 4 watts when, by size alone, it should have been closer to 10 watts. It also had big bulges on it with lots of wires running into it. There were no rules covering this at the time but next year the same panel was presented for scrutineering at the nationals and the team was not allowed to race! 2004 the track used was so bad that any half decent car that got up any sort of speed fell off! I think your car had this trouble, Marc? Then you won in 2005 and 2006. In fact, all place getters in those years ran maximisers, and it has been that way ever since. So, given a fair fight, it is reasonable to assume that cars with maximisers would have been winning at least in 2002 if not earlier. Box Hill have been running basically their same maximiser for longer than that but they are only now starting to do well, perhaps for the similar reasons?

John,

Yeah, I agree that cars using electronics probably should have started winning a few years earlier. Back then there seemed to be plenty of dubious things going on that were outside of the spirit of the event which prevented it from occurring. I can certainly see why Ewen threw in the towel in 2003 even though he could have still raced for another couple of years.

Yes, in 2004 many teams had trouble keeping the faster cars on the track. A lot of track sections were warped and sagged which really affected things. In some parts, it was so extreme that cars would just about disengage from the guide rail in one section, yet at the same time then scrape the guides on the track surface in others. Add a horizontal misalignment on the corners that caused the car to jump and you were off the track. Ok, I will admit that the guides on the 2004 car could have been lowered a few mm more if it wasn't for the screw head being used, but the car never had any issues with the Tasmanian track at the state event.
Anyway, the car had that many crashes during testing and racing over the course of the weekend that things eventually caught up with it.

Yes, all the top 4 placegetters from 2005 and onwards used electronics. In fact all but about a couple have gone without each year at the nationals since then. Last year in Melbourne no teams went without electronics.

miseli

Hi all, it's been a while! I apologize in advance if I offend anyone! To been honest I haven't read all the post above! There's so much! Suggestion, cut down on the history (write that on another post) and get to the point! =]

Ok, I've just got an controversial idea! Looking at last years AIMSCC results, the winning car had a chassis weight of 520gram. Imagine a similarly built car that weighed 300gram! Now the car with a heavier weight runs with no maximizer and the 300gram car runs with a maximizer! I wonder which one will win? So hence keep your chassis weight down without cutting corners as it becomes more fragile! And yes, I agree the regulation needs to benefit cars without maximisers to a greater extent.

jhg wrote:the winning car had a chassis weight of 520gram. Imagine a similarly built car that weighed 300gram! Now the car with a heavier weight runs with no maximizer and the 300gram car runs with a maximizer! I wonder which one will win? So hence keep your chassis weight down without cutting corners as it becomes more fragile! And yes, I agree the regulation needs to benefit cars without maximisers to a greater extent.

I don't see the logic in this. A lighter car is definitely more ideal, so i don't see how a heavier weight car runs with no maximiser. It will advantage the 300g car with the maximiser even more on top of lighter weight, so obiviously the 300gm with maximiser will win. Last year's winning car did have the possibility to reduce some weight, however the design was too heavily integrated to alter major changes.

Totally agree with firefly there. Jhg, did you mean a 300g car with NO maximizer and a 520g car WITH a maximizer. This then would probably be a tighter race...

Karo

PS. Hey firefly, was your car the same chassis weight at the state? Im guessing it was pretty major changes for the nationals...

Hello jhg,

It's good to see someone from over in the the west on here again.

As Karo has mentioned, I imagine that in your last post you meant it the other way around, where the heavier car runs with electronics and the lighter one goes without. If one reads it as it is written, then firefly and Karo are obviously correct.

Anyway, which one will win really depends on a whole range of variables. What is the panel power? What percentage sun level? One lap or 2 laps? The panel power to weight formula being used? etc

As firefly has indicated, a lighter car will clearly outperform one that is heavier if all else is equal. The most basic of physics will tell one this.
While the top speeds of the two will not differ by a large amount, it is the difference in car acceleration that is the key.

The reason why the regulations have a panel power to weight formula is to attempt to balance out cars across the 6W to 12W range over a race. Higher powered cars have a higher top speed (assuming car aerodynamics are consistent). To even things up these cars are therefore forced to carry added ballast to slow acceleration. Anyone ever heard of F = ma?

miseli