Solar Powered Go-Kart

Hey wow...sounds fun.

A couple of comments. (And I reserve the right to be wrong!)

a) You won't drive anything directly from the solar cells unless you have a vast quantity of them so a battery which is charged by solar is a more realistic option.

b) There are some good web sites out there, search for electric scooters etc...

I'd go for a DC motor for simplicity. There should be speed controllers off the shelf, or if you are ok with electronics you can build one (plenty of pitfalls though!)

Take care! These motors can run away with you...I built an electic golf trolley (Motor from a UK company Standel Dawman www.standeldawman.uk.com)

Probably not powerful enough for a decent Kart, but it may give you ideas.

Best of luck, let us know how you get on.

Del

you could just build sun roof over the top with solar cells on it then plug it into a batery

You'd need a couple of automotive batteries to store the solar energy, as a go-kart sized object probably wouldnt have enough surface area for solar panels with the output necessary for powering a rider+go kart weight.

So remember this:

1) Alternator, convert some of the solar energy or kinetic energy back to the stored chemical energy in the batteries.

2) DC like this alone wouldnt provide enough voltage to power motors like that. You would need a converter, then step-up transformer, then another converter to DC to power the motors

3) Try a solar-cell series parallel matrix, thats you're best bet for this because you'll need the balanced voltage/amperage. You can always step up or down again.

4) Just a thought, try mirrors on the hood of the go-kart to focus more light down to those solar cells.

Remind your son that it might not be the fastest or most impressive method of transportation, but that it is efficient.

Good luck bro, I wish I had a summer project as cool as this.

I have a also been dabbling in electric go-cart design, but mine is, ah, rather more powerful than your average petrol go-cart (think mini version of electric drag racer). I am a bit stuck due to the need for, well, a friend who knows how to build a chassis with a sports-style suspension. (I have just the person for the carbon-fibre body). A sort of latest technology test bed (forced-air cooled ac motors, super capacitor acceleration boosters, etc). It will likely stay in the initial design stages (also the price tag is a bit steep).

Anyway......

(a) - No. Batteries will be required. You will also need a solar regulator to charge the batteries. Standard sealed lead-acid are best (and certainly cheap). Flooded-type car batteries are far too heavy and are not designed for this specific application.

(b) - Like me, you should be able to use motor controller as the speed controller. Usually a potentiometer input is provided (although you could rig up a pedal to control the speed electronically), along with a stop and start button. Simple.

(c) - Try your local electronics store or surplus junk store.

(d) - It depends on what motors are available and inexpensive. Some allow direct drive to the wheels, but I think the best option for you is a single motor driving a belt and powering a single rear wheel. This works, and has the added advantage of making the go-cart more manoeuvrable than trying to run both the rear wheels off a common shaft. Also keeps the weight down and the power to weight ratio up. Overall the motor should be a high torque high speed type. Belt and pulley gears (the correct name escapes me for the moment) can be sized to give desired top speed and acceleration (performance).

(e) - ac or dc variable speed controllers. Simple, cheap motor control. The lower power ones should run of either 12V or 24V, meaning you only need 1 or 2 12V batteries.

Overall, you probably want to keep it as light as possible (perhaps aluminium tubing construction). This will allow operation using a small motor, and should be fairly inexpensive. If it is light enough, a stack of NiMH batteries may do the trick, Just remember, a standard 12V 50W solar panel is about 840 x 540 x 50mm and 6Kg.

Try Goggling "Solar racer", etc. There is plenty of information out there, and remember, half the fun (or more) is derived from actually learning about the existing and new technologies and building it (well it is for me anyway). Just remember to design it from the beginning to fit either your son or YOU and you will be fine .

Let's step to practical for a minute:

1. How old (heavy) is your son?

2. For your first project, try to use what's readily available then tweak that until you have the knowledge to KNOW what you want to build.

3. How much are you willing to invest in a "fun project"?

Suggestions:

A few years ago the Christmas market was flooded with electric carts for smaller kids - Barbie lawn cars jeeps etc -- here's your start. Power, speed control and drive train complete with gel pak batteries (read into this, a helluva lot safer than lead acid, and lighter too)

High efficiency, rugged solar panels are available from marine supply houses such as westmarine etc. and they usually come with their own charging regulators --

Might have to park two days in the sun to ride around for an hour but this is where the lessons regarding energy storage start. You can always plug the charger in the wall but that's cheating

You're now up to about $600.00. Is this where you're heading? Too much money or do you wanna get really serious as in the last posts?

And last -- OPINION:

I think its better to have an entry level project to excite the mind because it works but it can be made better through understanding, education and awareness than to grab a high tech project that will end up with expensive components in the garage that upset the wife, disappoint the child, make dad feel foolish, and never get asembled into anything that can be "played with".

To the previous poster with the dragster: Not knocking you at all. In truth, I'm jealous and would love to participate in such a project. But this gentleman appears to be asking entry level questions - - -am I wrong here?

Gaaah. Forgot to mention in my last post that you could modify a cheap store-bought go-cart and put a motor and solar panel on it. I didn't have these when I was younger .

Those electric 4x4 (quad bike) toys may be good for a higher performance modification option.

Dear Mike.

(a)-Yes- However, in British weather only in summer time you can expect sufficient power o/p. You can reduce weight by 1- Dieting or use light weight material. Use flat motors that fit on the hub.

(b)- Ideally electronic controller. There are various methods. You can make one or buy.

(c)-From junk yard. Alternatively search website.

(d, e)-DC.-Converting to AC is possible. Electronic gadgets are available.

(f)-Only brain and some technical knowledge. Good luck- Teach your child- He will be a good inventor.

Regards.

A helping hand.

Looks like we all want to join in...!

Plywood chassis construction is cheap quick, easy to repair/modify/bolt things onto.

Also more son friendly if he is too young to be welding!

Below links are solar cell site. They got it all from the looks of it. They sell scrap solar cells for $2.00/watt which sounds cheap compared to battery chargers I've seen in the stores. They say .16 watts/square inch (for their stuff). So one horsepower=746 watts=4662 square inches equals 32.36 square feet. Two horsepower would drive the kart if geared properly to probably 15 miles an hour (guess based upon childhood experience-most karts have 5-7 horse). So 32.36 times 2 equals 64.72 square feet. Not sure what efficiency of conversion would be but at 65 percent it would require about 100 square feet in order to get 2 horsepower to the ground through the wheels. You could put a arched top on it covered entirely in cells that would be 5 feet wide and 20 feet long and cost about $4,600 and would bore the kid to death because it was so slow. Believe me, I had a go kart as a kid that would do 60 mph that I crashed into a pickup truck. The first thing I did while in the hospital was to start designing a faster go kart. When I got home, I discovered my father had scrapped the wreckage and wouldn't allow me to pursue the sport further. My suggestion would be to try a project from Edmund Scientific. Cheaper, safer, and more realistic.

http://www.siliconsolar.com/commercial-solar-cells.php

http://www.siliconsolar.com/Solar-Cells-by-the-Watt-p-106.html

Hi Mikito:

First of all, from my knowledge, in Seattle there is not enough SUN. But I will thin k about you want to use it on California, Nevada, Arizona, or some place where the SUN is shining most of the year. Or in Washington when you get SUN.

(a) is is reasonable to expect enough power from photo-voltaic to move a go-kart with a fairly heavy load (say 150 pounds for the rider plus kart)?

It is possible with a efficient photocells over the complete top part of the car and with material that make the car not so heavy. Do not think you will get fast enough with the power of the photocell.

The best will be to charge the batteries apart. In a charging solar station. Ones charged to use them on the car.

(b) what type of speed controller is needed? Is there something available off the shelf?

For control motors depend on the motor used. Please take a look on this site http://en.wikipedia.org/wiki/Electric_motor

There are some speed controller available in the market. Take a ll ok if one will be suitable for the motor you chose.

(c) where can we get surplus electro-mechanical hardware to support this -- motor, solar cells, etc?

Just google them. You will find a lot of places where you can get this stuff. If you are lucky the Guy in the corner can have what you need :).

(d) AC or DC required for the motor?

Both can be used. Just look what you get and adapt your hardware to the motor :).

DC motor will give you power:).

(e) if AC, is there something to convert the DC to AC?

Yes, there is. Google them as Inverters or DC to AC converters.

Here you will find information about Inverters http://en.wikipedia.org/wiki/Inverter_%28electrical%29

(f) any other challenges we should know about -- other than the basic challenges involved in such a project?

-If you are going to use photocells have in mind that you will need a lot of area. More than 2 square meters. Look for flexible photocells. Are expensive but will be easy to adapt to your project.

-More heavy, more energy needed. Eliminate all the heavy staff from the car. Use aluminium or carbon fiber :).

-Eliminate friction. Air friction and wheels friction. Use thin wheels.

Keep going, do not stop if something from here make you think it is not posible.

There is a lot of things that need to be improved in a Electric car. You will find them when you start doing you own car.

Read this article before you start you design, there are some good topics and tips here: http://en.wikipedia.org/wiki/Electric_car

Saludos!

Del

With solar panels, there is always the option of using light-weight flexible panels instead. Far lighter due to their lack of glass plates and rigid structure (and safer to play with too). You will be limited to around 5-32W a panel, but it was unlikely that you would be putting a standard rigid 15Kg 175W solar panel on the cart (unless you wanted to use it as a roof. The car would have better performance than a house, but not by much).

Some links for flexible solar panel suppliers and manufacturers below. There should be suppliers of this stuff in the US.

Solar World http://www.solar-world.com/PowerFilm.htm

United Solar Ovonic http://www.uni-solar.com/

Kyocera Solar http://www.kyocerasolar.com

Global Solar Energy (unsure of link)

LOL!

Even with the flexible cell material, a piece that generates only 68 watts is 112.5" long by 15.5" wide! So to attain your meager 2HP you would need 22 of them, which comes out to over 266 sq. ft. of cell material! To give a perspective, that's about the size of an average yellow school bus (top surface area).

On top of that, each one weighs 8.7 lbs, so the cells ALONE would already weigh almost 200lbs, and that is not including some way of supporting them all for maximum solar exposure! With even light wall aluminum tubing, I doubt you could get the frame weight below 100 lbs, so now you are up to 300lbs. before the kid even sits down in it. Add a 2HP DC drive and motor, a gear box (because moving all that weight ain't gonna be easy), a seat and a steering mechanism and I doubt you are going to come in at under 500lbs GVW.

He had better not be a chunky kid!

http://www.prin.edu/solar/

Hello guys,

Great thread !

I am working on a light vehicle for 2 people to commute during the day and allow either pedaling when there is no sun or solar as I have 320 days of full sun here.

My city, Chihuahua, is highly contaminated as there is no MOT or pollution control.

Also because 90% of the people here are broke, I would like to stay below 3000 USD.

Here is my project :

Connect 2 identical bikes together. Good thing is that it already has brakes, dynamo light, etc

Quick question : because I can just pedal when there is no sun, I would like to avoid the battery and simply connect the 3 solar panels (each panel can give 180 watts, so that is 540 watts) directly to the DC motor.

Not using the battery would save me a nice amount of weight. Not only the battery but also the battery support, etc,,, And of course money !

Is it reasonable to do ? Would I destroy the engine that way ? Also is there any small electronic which can give me on real time the power delivered by the panels so I know if it is worth connecting the panel or not ?

And last, the "kart" weighting about 60 pounds, are 24v (I think) -500 delivered watts enough to tract 2 people ?

Thanks a lot

Philippe

Ahh, have you looked at the 180W solar panels you are proposing to produce the necessary 540W. A standard 160W 24V silicon solar panel measures roughly 1600 x 800 x 50mm and weighs 15Kg (33 pounds. Each). That gives you an extra 45Kg (99 pounds) which is effectively trying to pull the dead weight of a second person along. Thin film panels weigh much less but require much, much more area to get the power you are proposing (certainly too much for a practical small vehicle such as yours).

You could leave off the battery but you are NOT going to get 180W continuous out of each solar panel as the panels output depends on light level and angle to the sun, you can realistically expect half or less on a cloudy day, and even less if you mount half the panels on each side of the vehicle).

Given all the energy you will need to waste pulling all this extra weight the benefit of adding heavy and bulky solar panels is likely going to be a hindrance to your vehicle (this is why existing solar panels are only used for assisting small loads (like your dynamo powering a small lamp) rather than providing propulsion).

Given all the above I think you would be much better off with an energy efficient battery-powered motor (greatly reduced weight and greatly increased energy storage), or perhaps a cleaner-burning internal combustion engine. The key is to keep the weight down. A light-weight design should be your goal, as less weight means less fuel needed to travel (fuel as in food for peddlers or electricity for motor or gas for engine).

If the distance is short (or the terrain flat) how about just a very cost effective and light peddle-powered (only) vehicle using local resources.

"If the distance is short (or the terrain flat) how about just a very cost effective and light peddle-powered (only) vehicle using local resources"

I want to allow women to do more things and not simply rely on the neighbourhood or random-scheduled buses.

Ok, but my point was a cheap light-weight single person vehicle that could provide simple and efficient transport, for either a single man or woman. It was only another idea after all and would depend on terrain and distance as much as target customer's fitness.

Thank you Jack. I do take your suggestions in consideration.

I am confused between the power of the panel and the power of the engine. Is it the same ?

Like, if I have a 400 watts engine, and 400 watts offered by the solar panels - OK in optimal conditions, that is maybe 1% of the day - I am trying to find out how much of a solar power is needed to move a one-person bike on a flat area at 10 mph. Aprroximatively of course, because a person can be 120 or 200 pounds...

Then, is a power of a 400 watts-engine reasonable for each person on the quad ? With flat, slightly up (10 degrees max) streets ?

Thanks a lot

Philippe

As a really rough explanation if a motor has a rating of 400W then it can produce 400W of pushing force for your vehicle. If your vehicle is light enough and the street is not too steep then the motor may only need 350W of power to push your vehicle along.

How large a motor you will need will depend on many factors, such as vehicle weight and what gear ratio you have between the motor and the driven axial (assuming some sort of belt or chain drive approach). If you keep the gear ratio high so that the vehicle doesn't move too fast then a small motor can move a heavy vehicle.

Unfortunately I don't have any information on me to say if a 400W motor is viable in your application (ignoring solar panel weight). I would say yes as 400W is around 1/2 horse power, but using just solar you may only get on average 1/4 or 1/8 horsepower which I think is far too little to push all that vehicle weight.

Perhaps you could start a new post on CR4 and ask this question (providing as much detail as possible). I am sure there are others who have some first-hand experience in doing what you are proposing and can offer more specific advise.

Hello Mike,

I saw an old post you made about building a solar go kart. I have built one. You can find it in the 2005 photos on my www.SolarDragRace.com site. More specifically, you can see pictures of it at the bottom of

http://users.applecapital.net/~jim/photos.htm

It is simply an electric go-kart I bought at an automotive parts store with a standard 165 watt solar module mounted in top of it. I built the support structure that attaches the solar module to the go-kart using foam and fiberglass composite materials. There is a charge controller between the solar module and the go-kart battery to keep the battery from getting overcharged.

Jim White

Hello Mikito, So, very curious to learn... after two years has passed, how did your project go with the solar powered go-cart? I am going to start a similar project this week. I have been thinking about it with my 8-year old son who is homeschooled this year. Please let me know your experience and where the go-cart experience took you. Thanks! Max

Max -

Good to hear you're also interested in doing this project.

I only got as far as planning it out and spec-ing the more costly items. Then time and money ran out so I couldn't actually do it. If you manage to do it please send along any information you can share! It should be a fun way to spend time with your son.

Mike

I built a solar powered go-kart four years ago. Each year it is driven by every fourth grader in our city (approximately 300 kids per year). I started with an electric go-kart that was purchased from the local car parts store for about $200. I constructed a foam/fiberglass support structure to hold the 165 watt solar module on top. The solar module is connected to a charge controller that is connected to the go-cart's 24 volt battery. The purpose of the charge controller is simply to keep the battery from overcharging. In the four years that I have had the go-cart, I have never had to plug it in to charge it. All of its energy comes from the sun. You can see pictures at:

http://users.applecapital.net/~jim/Solar%20Go-Kart3.jpg

I converted a gasoline go-cart to electric. It runs off of a 1.5 pound lithium ion battery pack from a Dewalt power tool 36 volt battery pack. The pack is charged by a stationary 175 watt solar module. It runs for about 7 minutes at full throttle (1 HP) before needing to be charged again.

http://users.applecapital.net/~jim/Dawson%20Kiaya.jpg

Jim White

Wenatchee, Washington USA

jim@applecapital.net

Hey that is very COOL... I will get to work on this - my son is excited and can hardly stand any more research on this. He wants to build it. But we need to know what we are getting into. Thank you for sharing your project as I am sure that you have influenced every kid that has ridden it!

I found this solar go kart on northern tool website. It has a 24v battery system, so it's not 100% solar. The solar panel just extends the ride time. I'm sure you can upgrade the panel and get much better recharge on it. The panel they use is a basic one suited for retailers, but it serves its purpose. Nicely built. Hope this helps http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200394263_200394263

Hello, Thanks for the info. interesting. We are looking into what is available and so, might adapt an existing model with a custom designed solar panel - this is quite a project and I am glad to have CR4 to "dialogue" with!

Saw this on the net...

http://www.sears.com/shc/s/p_10153_12605_00697511000P?vName=Fitness+&psid=NEXTAG01&sName=Electric&cName=Scooters&cascycle=true&sid=IDx20070921x00003j#

also for some ideas, have you seen "The Colony" on Discovery? Late in the season, they built a solar powered vechicle to explore around the area.

My thought would be it would be difficult to run the kart directly off of a panel(s). The example above is a 350 watt dc motor, so you would need multiple residental sized panels to generate that amount of power. So you are back to batteries... better idea is to have a battery kart that can be recharged slowly with a small 40-80 watt panel as a roof or on the back.

RE: Glenn

Hello Glenn, Thank you for sharing this info. I found this earlier and am working on getting it. I am learning a lot from this project. It is cool that we have this forum - I am inspired by all of you and hope to contribute to your projects as well. Experience is the best teacher... got to go through all the pain before arriving to the destination (sometimes not the planned destination!) but a great voyage! Max