I don't need the full range that a golf cart normally has, and
don't need to go as fast, so I'm thinking about using the same motor and
controller as a golf cart, just with fewer batteries (to reduce the
weight, and get by with lower voltage and battery capacity).
Has anyone else done this?
Some people have done it. What I really like about the Elec-trak is how drop-dead simple the controller is. Even on my old Craftsman I found that 99% of my time was spent with the engine at full, the speed in gear 3, and mowers engaged.
And with the Elec-trak, 90% of the time is spent in speed 4 (full field, full armature) and L2 (for nice mowing). The rest is spent in 4,LL for blowing snow.
So if you have a two speed controller with a resistor to slow the startup you should be in business. Just run the motor full power and find the gear that allows you to mow.
Or you could buy a nice E-12. Simplest of the big elec-traks; it has 3 speeds, 4 gears, no waiting. The E20 is maybe nicer with the extra high speeds, but they always seem to give people trouble. And the E15 with electronic controls tend to drive people to AllTrax systems.
Chris