Karl Townsend wrote:
On Sun, 13 Feb 2011 09:49:54 -0600, "Pete C."

PWM DC motor drive

like this one?
http://www.electronickits.com/kit/co.../CANUK1133.htm

Looks perfect, assuming it's guaranteed to operate at your battery voltage.

I can vouch for PWM DC motor control - you can maintain full torque
down to zero RPM - with a permanent magnet DC motor (which I'm ass-u-me-ing
you have), the torque is proportional to the current. (not too sure about
a series-wound, or "universal" motor, but I'm guessing it still applies.)
I've designed and built a PWM motor speed controller, and it's pretty
awesome to watch it maintain full torque at any RPM. This was only a 1.5
amp motor, but the same principle applies; buying one that somebody else
has designed, built, and tested is obviously better than trying to klooge
up something on your own, unless you're on a learning mission. :-)

Cheers!
Rich