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solar pulse motor help! Answered

Ok so I have two questions. First I have a very week solar panel like it can't even power a motor I can power with a AA. I would like to know how to test how much voltage it can produce. Second I'm wondering if I could use this week solar panel to charge some little capacitors which would charge up and then discharge with enough voltage to power my motor. Would this work? thanks for your help!


I am guessing you are wanting to build one of the BEAM solar engines.

If you have not heard that jargon before, a "solar engine" is a simple circuit that uses a weak voltage source, like a small solar (photovoltaic) panel, to store energy in a capacitor, then discharges the capacitor, whenever it is full, across a motor to produce a short burst of movement.

That word "BEAM" is an acronym, a name for the philosophy of this kind of robot building.

You're probably more interested in the circuit recipes, which can be found here:


The Wikipedia article for "BEAM robotics" can tell you what B.E.A.M. stands for, and also gives a good overview of the philosophy, and the people who invented it.


Or you can read about from the org themselves, here:


heh, it is great

If too weak consider getting some cheap solar garden lights and to set them in a series/parallel configuration with protection diodes.
A capacitor won't be of much use for a motor, use a rechargable battery - if in doubt use the collected soloar garden lights directly just to charge a bunch of these solar batteries during the day ;)

Either from solar garden lights or the corresponding section of your favourite hardware store.
The are NiCd batteries with a quite low mAh rating matching these small solar panels and the runtime of the LED's (6-8 hours).
But you might still want to get at least one solar garden light to get the charging and shut off electronics.
Just connect the motor to the LED terminals - if it is small enough!
Otherwise you have to add a transistor and protection diode so the high load of the motor won't burn out the electronics.
So using multiple panels and batteries might be a good idea.

Vibration motors from old mobile phones are often good for this if you remove the weigth from them and have something to fit the axle.


1 year ago

How long to run motor ? like the AA or do you want longer ??

Little rechargeable batteries will work much better then little capacitors.

It may take days of charging to run the motor for a few minutes. Put a diode in series with the solar panel to the battery. Otherwise the battery will discharge into the solar resistor when a cloud appears and at night time..

Use a Harbor Freight $7 multi-meter to measure the voltage minus the o.7v diode drop on a sunny day.