This question is related to a science project with my son. We are
trying to power a small 1.5 volt DC motor with a 350 mAh, 5 watt solar
panel. With a 250 watt light shining on the panel, we cannot get the
motor to run. I know that tiny solar panels can get a DC motor to run
well. What are we doing wrong?

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Clarification of Question by glowplugboy-ga on 25 Oct 2004 21:45 PDT

I don't have a voltmeter, but the motor does work normally on with a
AA battery attached. I looked over the box the Solar Panel came in and
I noted that it has a blocking diode that prevents battery discharge
when this unit is used as a battery charger. Would this diode make any
difference?

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Request for Question Clarification by sublime1-ga on 25 Oct 2004 23:51 PDT

glowplugboy...

In researching, it seems that every 5 watt solar panel I came
across has a 12 volt output. The only one I saw with a 1.5
volt output was a miniature panel, so I suspect your problem
is that the voltage is too high. Assuming the motor still
works with the battery, and hasn't been burnt out, you 
might want to try a smaller wattage light source, or a 30 ohm
resistor in series with the motor, to drop the excess voltage.

This page might interest you:
http://www.siliconsolar.com/beginner_solar_demonstrational_k.htm

Let me know where this takes you...

sublime1-ga

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Request for Question Clarification by sublime1-ga on 25 Oct 2004 23:53 PDT

Oh...and the diode is not relevant here.

Does the motor run when connected to a AA battery? Try spinning the
motor shaft without the panel connected. Then try with the illuminated
panel connected. Is there a difference? Does the shaft seem to want to
spin by itself? I assume you don't have a volt-meter...