i have to do a science fair project and thought it would be cool to make a solar powered vw bus. i have 2 6volt solar panels to power a dc motor that works off of 9v 2v or 8v. i also bought a 2nd motor because the first wasnt workin for us. this one is a 3v motor. ive had them in the sun but they wont work. please help, thanks
A 2V battery designed for a current max of 200mA, can turn on a 2W lamp. If you want to turn on a 2V 200Watt lamp, you need a bigger battery capable of providing 6 amps!! Similarly the solar panel you have can produce a voltage, but when connected to a motor, the voltage might drop to much lesser value!! So apart from voltage you also need to know current taken by motor. Further, motors have a habit of not starting, but once prodded (mechanically rotate the shaft with hand), they may run. If you are in that border area, give a turn to the motor and see.
You didn't say how much power your panels can produce, or how much power (current x volts) the motors require. The panels must meet or exceed what the motor requires. You might need to get a very small motor and a little gearbox out of some other motorized toy, or at least a small pinion gear for the motor and a larger ring gear that can be attached to an axle (similar to how RC cars accomplish their drive train). A worm gear drive set might be even better if the motor / solar panel combination isn't very powerful - it'll go slowly, but some movement is better than no movement. If you put the panels in series, a 2 V motor should be the best match (again, only if its power requirements are small enough). If you want to try running the 3 volt motor off the panels, you might try paralleling them (make sure you get the polarity right or they'll try to kill each other) - you'll still be mis-matched, but if the motor requires less power than the 9/2/8 volt motor(s), it might work. If you have or can acquire a multi-meter, you'll be able to measure the voltages and currents and that will not only help you see what's going on, but adding some details might help others help you get this working.
