Solar Model Cars
Information and Resources 

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Solar Model Cars Resources for anybody planning, contemplating to or building a conventional, RC or solar powered model car.

Below you will find Links, hints, tables and information for that unique project.
Eventually we will have the resources in alphabetical order and perhaps some search facility.
For now I will list the solar model car resources as they become available.

Wheel alignment and Steering geometry are essential parts of a successfull solar powered racer. Incorrectly aligned wheels or steering geometry will cause friction and drag, which in turn chews up energy and slows your car down.
Incorrect steering geometry will cause oversteer or understeer, making it difficult to keep your car on track when racing and causing collisions.
As the solar model cars become more competitive and faster, any friction or drag will cost you seconds of time, this will add to minutes with each additional lap and eventually undermine your success in the race.
Recently, whilst mentoring young students for a solar powered model car project, I required some information on the wheel alignment and steering.
Here's a brilliant explanation: Model Car Handling - Ackerman Steering Principle


Radio Control At almost every race we had problems with remote controls interfering with each other because they have not been tested in close proximity to each other prior to the racing event. Testing the Radio Controls should be done weeks before a race so any problems such as incorrect or duplicate channels can be corrected before the racing day. Make and keep a list of the allocated channels and double check them just before the race. Any changes must be disqualified and disabled to avoid interference.
Information about the radio control (R/C) equipment including transmitters, receivers and servos used tocontrol model cars. Radio Control Basics for Solar Model Cars


Differentials, what they are, what they do and the different types of differentials that can be fitted to radio controlled model cars and solar model cars. Differentials for Model Cars


RC model cars resources The site below is devoted to radio controlled model cars. Whilst not specifically intended for solar model cars, it is still a valuable source of information. It is the publishers intention to provide a valuable, unbiased resource for the general public and trade alike. Please Note: The site does not sell anything. It exists purely to inform the model car enthusiast about radio controlled model cars (RC cars). Solar model car resources. RC Model Cars Resources


Photovoltaic (solar cell) systems for students and teachers Our solar powered model car project makes good use of a BP Solar panel.
The following resources Site will help you learn more about photovoltaic (PV or solar cell) systems and applications. http://www.nrel.gov/learning/


Jon has developed a simple computer model that predicts the panel performance at various voltages.

You will notice that the open circuit voltage (Vo/c) reduces as the panel heats up. The short circuit current (Is/c) reduces with less sun light. Both cause a reduction in the Power available from your panel.

The purpose made spreadsheet allows you to determine the peak power under a range of conditions. Just enter Vo/c and Is/c measurements from your panel into the yellow fields and you can see the effect on the peak power point (Vpp). Enter the "tested" figures off the back of your panel to confirm the accuracy of the model. This is important in terms of choosing a battery voltage that allows your system to operate at this point.



Electric Motors to suit Solar Powered Model Cars

We have searched far and wide for a suitable 30Watt motor for our solar powered model car. Initially we experimented with battery drill and screwdriver motors as they have integral gearing, unfortunately all require excessive current generally in the order of 4 to 20 Amps at voltages from 7.2 to 18 Volts.

We then "discovered" electric car-radio antenna motors to be about the closest to the stipulated 12 Volt 30 Watts. Their current requirement is an ideal below 2.5 Amps but the motors are generally inefficient and not designed for continuos use.

Rc racing car motors and some exotic electric model aeroplane and helicopter motors are small, light and very powerful but will generally require well over 10 Amps. Curious? Go to: www.modelflight.com.au

Whilst searching for a suitable motor to suit our solar model car project I found the core-less rotor system Faulhaber motor, series 3557CS. This is a high performance graphite commutation-type ball bearing motor made in Switzerland and Germany. They also make some superb matching planetary gear-sets, go to: Minimotors for the Solar Model Car


Reduction gearing. Do you need reduction gearing? Here's a good belt and pulley reducer kit with ratios: 2:1; 2.5:1; 3:1; 4:1; go to: www.robotics.com/pr23.html or consider making your own.

Timing belts and pulleys. Here is the link to an Australian supplier of cost effective timing belts, pulleys, bearings and parts as used in RC cars and suitable for solar model cars.www.smallparts.com.au

Spur gears. Joel from Maquarie Textiles suggests the following site www.tea.com.au is a QLD company that has spur gears. I am told that they are quick to send their products out. As suggested by Trevor if you go to their American site www.teausa.net they have the PDF files on their gears.

Facts about ball bearings Not happy with the newly aquired bearings, we searched the web for an explanation. We found some meaningful information at edsbearings unfortunately too late for this year's (2004) race.
After several races I come to the conclusion that ball bearing wheels are too heavy, good plastic pram wheels are lighter and cheap enough to replace if damaged or worn. Use Molykote 33 or equivalent grease on the axles.

Tubing for light weight, hollow axles. The Albury Hobby Centre in David Street has a good selection of brass tubing and shafts.

Aluminium angle, flat and tubolar in short 1m lenghts and different grades are available from Bunnings Stores.

The battery for our solar powered model car project.The battery in our project acts as a regulator and is limited to 2V/Ah which, to my calculations, equates to166mAh (166 milliamps) or 0.166 Amph at 12 volts.

The nearest commercially available Ni-Ca or Ni-MH battery is a 2.4volt, 150 mAh pack as used in some computers and cordless phones.
To make your 12 Volt battery you need 5 packs connected in series. They have solder tags and are easily assembled on a piece of Matrix board.

The Varta 2/V150 from Jaycar or an equivalent from Dick Smith or Tandy would be ideal.
If you experiment and find your solar model car performs better by adding an additional 2 battery packs to make 16.8 Volt, you will have to reconsider the total capacity of the batteries. You would now have to change to a 120mAh batteries to get below the 2V/Ahlimitations.
Commercially there are 80mAh and 110mAh batteries available. You can buy wholesale from WES Components of Ashfield NSW, ask for 4.8V AKAI video back up battery, RB303, and you will get a pack of 4 cells, 110 mAh for a reasonable price.

Please do not short circuit, mix the capacities, types or brands of batteries when building your project, the batteries can get hot and burst or explode causing severe injuries.

Note that 2.4, 3.6 and 4.8 Volt batteries consists of a number of 1.2 Volt cells bonded in series and packed in a heat-shrinked plastic jacket, you must dismantle the pack if you require individual 1.2 Volt cells.
Be very careful with the solder tags, they are spot welded to the stainless steel casing of the cell and tend to break off with the slightest pull. Avoid soldering directly to the casing as the heat will damage your battery cell.
On our last meeting, Friday 5 March, it was decided to purchase the battery for each team. Each team will now have the same capacity battery.

An interesting site for solar power Welcome to Go Solar Power - Your best source for solar power!


Planetary gearboxes are the best and also the most expensive. Consider using the planetary gearbox from a rechargeable battery drill. Most of them are a two stage type and have a very high ratio. If you "freeze" the output stage you can get a usable gear ratio. To freeze a stage, dismantle the gearbox, clean and degrease every component and reassemble using Loctite or Araldite to freeze the planetary gears of the output stage. When the glue has set, dismantle the gearbox assembly again and grind or cut off the protruding gears whilst keeping them cool. Do not attempt to weld the gears, as they will disintegrate. Clean, lubricate and reassemble.

For an interesting model car resources article from Chuck Wright on combining Motor with the PV Panel go to:

http://chuck-wright.com/SolarSprintMotorPV/SolarSprintMotorPV.html


A guide to basic driving skills. Intended primarily for novice rc car drivers, the Tamiya guide to basic driving skills is quite suitable for our solar model cars project.
Bear in mind that many of our young students have had only very limited driving experience and even less car racing skills.
This simple but effective guide will show the viewer where to look whilst driving. Cornering techniques like what’s “slow-in and fast out”, tacking-in and counter steering,and many more “seconds-saving” skills that will win a race, and more importantly, the fact that the fastest car will not necessarily win the race, but a good driver can. If you'd like to print the guide, it's best in landscape format.

Tamiya guide to basic driving skills. Don't miss this step! if you're serious about solar model car racing, specially with a taem of young drivers, give them the chance to practice.
Ideally have the solar car finished, ready and running a few weeks before the race, and use the time to practice driving it. Get each team member to do a few training laps, then start timing with a stop-watch and keep score. Persist and get each team member to get close to the best time. The above procedure will train your driver and test your car. If you have break-downs get the team to brainstorm the repairs or modifications, then do the fix.


Solar Powered Flight, Circumnavigation of the World in a Solar Powered Plane. Following his non-stop round the world flight in a hot-air balloon, Swiss adventurer Bertrand Piccard is preparing for a new adventure: a circumnavigation of the world in a solar-powered aircraft. The project, called “Solar Impulse” brings together the elite of the European scientific community, and is scheduled for take-off in five-years’ time. For more information go to: www.solarimpulse.com


Back to the Solar Powered Cars Page
Action Pictures of Solar Powered Model Cars


This Solar Model Car Website was created by Henry with SBI!Sitesell