Low Power Motors

[Jdog]

Hi. I am building a solar panel array that will track the sun. For this apparatus, I will need to use motors that consume the least amount of power as possible (because it is running off of batteries) but can still move a large load (60-70 lbs.). It does not have to move very fast though so gearing down is an option.

Which type of motor (DC, brushless, stepper, etc.) would be best for this application?

[Ro-Bot-X]

If I were you, I would start with the battery voltage. Say it's 12V. Then, I would start looking for the 12V motors that use the smallest current at stall, perhaps under an amp. Use a SN754410 H-bridge to control them. Connect the output shaft of the motor's gear box to a threaded rod and use a nut on the rod to move the load. This way you have the most power out of the motor and the least speed. Make sure there is little friction on the threaded rod, grease it, align it, straighten it, etc.

[Soeren]

Hi,

Whatever motors (I'd go for small and surplus), make sure you don't run them continuously.
Waking a controller eg. each 5 minute and do a tracking will be just as good (in terms of max. output from the panel), as continuous tracking and will waste much less power.
Perhaps you can stretch the nap period to about 15 minutes with a negligible fall in efficiency (experiment), to make it even more lean.

Btw. Gearing down isn't an option - it's a necessity!

[blackbeard]

Old drill motor maybe?

[Robo]

Check some of the surplus houses.  Electronic Goldmine and All Electronics both have a good selection of gearmotors that should work.  If you keep everthing balanced and well lubricated it will take very little power to move the array with a worm drive.  Put a timer on it and after sun-down have it reverse to be ready for next morning.