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 hey we'r makin a solar powered boat for a techfest...it needs to run on solar power provided by 3 500 W halogen lamps..motor is 6V..we'r usin 6 solar panels of 6.5 V and 900mA..ther's a tunnel for a distance of 400mm(4cm) which means we hv to use capacitors for charging when energy is there nd to discharge when solar cell is not workin...also wer're connecting a diode in series with the solar cell ...we'r usin 5 capacitors of 4500uf each..the problem is that the dischargin time of the capacitor is only 2 sec..i dn think tht will b sufficient for runnin in the tunnel...do we need to add mor capacitors or change the circuit...also suggest if we need to add mor than one motor to increase the speed .plz suggest nd giv us sum tips nd answers..plz event is only 2 days away..plz reply fast....




8 years ago

Just checking...  are the capacitors connected in series or parallel?  They should be parallel.

How fast is your boat?  How far does it travel in 2 seconds, and how far does it coast when the power runs out?  Is the tunnel 400mm (40cm) or is it 4cm?  That's a big difference!

Search the web for solar engine.

There are several varieties, but they all use the cell to charge a capacitor or battery, then dump the charge through a load (eg motor) when the cap is full.

If your boat is streamlined, it could coast through the tunnel.

Alternatively, look into a pummer circuit - it charges in daylight, then dumps charge through a load when it goes dark.  Combine the pummer with the solar engine, both dumping their charge into the same motor, and you could have a winner (just remember to use diodes to stop the solar engine charging the pummer and vice versa).

Ooh, I like the Pummer circuit.  Holding the cap. charge until needed in the tunnel.  I never even thought of that.

If its the usual rules, you get a time penalty from charging first, and the best time, according to one of my mentored friends was about 10 seconds from one end to the other !

I've answered a LOAD of questions on this recently. Take a good look from the search box.

Don't get hung up on the tunnel. Odds on, the momentum of the boat will carry you through.

Pity you didn't start planning this some time ago....

Is the motor specified and everybody is using the same motor?  Or can you get a more efficient motor?

What are the specs of the motor you are using.  I think to figure out the best combination of parts that info would be necessary.