Solar-Powered Tricycle (two-person model)

I have an ambition to drive around New Zealand with my wife, in a trike powered by the sun.....

If I build a light, two-person vehicle from two bicycle frames, I reckon I can mount two 140 watt solar panels as a roof (doubling as a sunshade) over our heads.

There would be a bench seat to sit on, and two pairs of pedals for us to help the solar panels along for when the clouds come, (or the hills!)

The panels would be connected directly to a small 24v electric motor, which would drive the back wheel (or wheels?) when the sun shines.

No batteries, they're too heavy.... perhaps?

I've been told that a person of average fitness can pedal continuously without getting tired, at about 100 Watts, with bursts of hard pedalling up to 200 Watts for short periods. This means that one 140 Watt solar panel can generate energy equivalent to one persons' pedalling! If I fit TWO of these panels, and if the vehicle is light enough, and if we don't eat too much, we shouldn't have to pedal very hard to keep the thing going!

What do you think?

...Two years later, and the Trike is now a (partial) reality!

Except that it's a 4-wheeler, so we've decided to call it a QUIKE instead of a TRIKE. 
Here it is, in all it's colours (we painted it up so that we could ride in our local Santa Parade - and it was a great success!)


(By the way, the purple flags are COMPULSORY - it doesn't go without them...)

Here's another photo, a little closer up, so you can see how the frames are bolted together with strips of wood clamping onto the frame.  This makes it easy to disassemble the Quike again, in case you want to use the bikes normally.


Notice that the seats are positioned well back, behind the original seat-posts.  The handlebars have been moved back as well.  The steering is by means of a tiller operated by the right-hand driver, (and the brakes are operated by the co-pilot - you have to be able to co-operate really well!)  The two front wheel handle-bar shafts are tied together with a "drag-link", so that they turn together.  I've arranged it so that the inner wheel turns more than the outer wheel when going round a corner.  This means that the wheels don't scuff on a curve.  (Ackermann wheel geometry - you can look it up to see how it works.)

Here's my son and daughter going for a test-drive.

We've discovered that the center of gravity is rather too far back - if the hill is steep, and we push too hard, the front wheels tend to lift.  But it's ok if we have a 20kg load in the front carrier.  So when we go to town, we carry 20kg of water as ballast, which we jettison and replace with our shopping for the trip home.  We have a little bike computer rigged up, so we can see how fast we're going.  We average about 17km/h on our trip to town (a distance of about 8km), with a top speed of 37km/h on a downhill bit.  (Fairly scary stuff!)

We were concerned that because of our width and our slow speed, motorists might become frustrated and get angry with us - but all we've had so far has been friendly toots, laughter, and cheery waves as people go past.  (Now I'm worried that we might cause an accident because of drivers turning to look at us instead of watching the road!)

The next part of the project is to fit a couple of small electric motors (one for each side), powered by two 130 watt solar panels mounted on the roof.  We have two Kyocera panels, and a couple of radiator fan motors (from wrecked cars at the local dump), which are rated at about 150 watts each.  They should do the job just right, I reckon.   I intend to gear them down about 16 : 1 with bicycle chain and gears, and drive the biggest cog on the pedal crank directly from that.  This means that the pedals will go round all the time, but since this is intended to ASSIST the pedalling, that's probably ok.

I'll keep this page up to date, as we make progress with this project...

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