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Solar engine for a solar boat Answered

 Here of some of my queries.
 we need to run a solar powered boat on a 1.4meter long water track in a shortest possible time( max time 5 min given)........
so i would be glad if u let me know the correct solar engine circuit to it..( i mean the capacitor selection , solar panel specifications etc etc)
also there are many slar engine circuits online..which one do u prefer (1381,FLED,millers,zener based etc etc)
          waiting for ur reply....... thanx in advance........


If you've got the light source for the whole of the time (either sun or electric light), forget all about the extra components. All you need is a low-voltage high-efficiency motor and as many solar cells as you can get on your boat (but bearing in mind the heavier it is, the slower it will accelerate).  Don't worry about shoving too much voltage up the motor - It's only got to run for a short time.

I've no practical experience of building these, but I'd have a look at making something like THIS (only smaller ;¬) using a motor with a pulley to a larger pulley on the paddle (reduction gearing).  Water on the belt may be a problem though. 

As Lemonie says, we need more info on the rules.  We won't design it for you, but we'll probably give you a few ideas.

The Toyota challenge that Rapid are sponsoring in the UK is rather similar, but based on dry land. You get 15 minutes under a  light source,and then you have to goes as fast and far as you can.


hey guys i m particpatin in d same competeion nn    desprately need ur help.

i dnt hv n e practical experience with solar engines. i bought my self a 4700 micro farad cap and trying to build with it. can any one tell me how can i increase the tripping voltage for ic 1381 .. i have 1381 c   and its trpping voltage is very low 2 volts .. how can super capacitor help me ?

Any rules about mirrors ?

I was thinking of EXTERNAL mirrors....You can collect light and shine it on your panels and get a lot more energy from them.


 First of all thank u for ur thought...its definitely a good idea...but i was doubting whether using any external mirror may 1.increase the net weight (it should have a stand too) 2.it may cross the size barrier given ( 25*20*20 cm^3) 3.it may easily imbalance the boat because the mirrors will be kept at some height of the panel to focus the light .....
 Any other idea steve....plz do think abt this... :) ...
      awaiting ur reply...

There doesn't seem to be a rule that says you can't all stand there and reflect a bit more energy onto the boat, is all I am saying.

Otherwise, you've got some experimenting to do.

I suggest the pager motors as they are VERY small and remarkably powerful.

You could possibly drive two differentially, and make the boat follow a laser beam or other source down the tank, provided you can prove it isn't powering the boat at the same time.

Don't get hung up on the solar cell bit yet, try the thing using supercaps or batteries first.

See if the motors push the boat props effectively.

Avoid gearing if you can.

Experiment by a control for the motors that allows you to push the boat at different speeds. Is there an optimal speed ? 

Make the boat long and narrow will make it faster. Or a catamaran ????

What about ducting the props, like a jet ski ? Is that more efficient ? 

Use the best cells you can afford. The light source is not very good - a metal halide source would be better, you'd get more visible light for the cells, so see if you can find cells that work better into the red-der part of the spectrum.

See how much energy you can reasonably pull from your solar source. You have five minutes to race in. Is it allowed to sit there for 4:50 seconds, collect energy, then sprint for 10 seconds ? Do you record a 10 second time, or a 5 minute time.

Think inside out, outside in and upside down. The "correct" solution is the one that wins within the rules given.

Thanx for your advice steve....
there is no optimal speed set for the boat..
and the time would be counted as 5 minutes and not 10 seconds...
I will try to implement the mirror idea...Thanx again for your advice... 

That's interesting. A small panel won't give you much power, and you have to get everything from the 3 bulbs. One might think of - charge - move - cut motor & charge - move (tunnel) - cut motor & charge - finish. That would require some clever electronics. You might also think of charging at the start line and going the distance on that alone.
I'm thinking it would probably be a good idea to have this steer towards light - there'll be enough on the internet around that subject I'd think.
And you want an efficient hull & drive.
None of these look fantastic, but they may give you ideas:


 Thanx to your reply , lemonie ...
    Your attached link will surely be a great help to me...
     It would be great if you send some more links like these... :) ...

I just went looking on the internet for "solar boats", with words like "contest" - no special knowledge.


Could you provide the rules / specifications for this contest? It's not going to help you if you're given an answer which you can't implement.


Nicely stated problem. Use a panel to pump a super-capacitor ? Use a pager motor ? keep everything small and light.

It wouldn't be very ethical to tll you how to design the circuits though.



8 years ago

I recommend you poke around these sites for either a schematic or kit (respectively):

Post some links to the circuits you think will work. 1.4 metres is a VERY short track, so presumably your boat has to be very small.

I'd look at things like pager motors to drive the boat.