Home Brew Challenge for Electric Geniuses (make a DIY electric motor controller)

[NoCO2]

That sounds similar to what I built for my RC car (I think). The way I made the mechanical speed controller was that I had 3 contact points on a surface and an armature that was moved by a servo. The first contact point used two resistors to cut the power back for slow movement and early acceleration. The second contact point used just one of the resistors so you received more current to the motor then before. The final contact just went straight through from the battery to the motor, no resistors...Something like that in a larger scale with more variable points might work well for this application. It's not a solid state solution but it would definitely get the job done, all be it inefficiently.

[MetroMPG]

Similar, but the old drum contactors in the EVs didn't typically use resistors except at the lowest setting (for creeping). They switched the batteries around eg. from 6v to 12v to 36... etc. Other than the creeping speed, it was all direct connection from the pack to the motor.

[cfh]

before you guys get too far along , take a look at the OSMC project ( that's open source motor controller (grin)) : Robot Power OSMC Project Info

mind if you want to head off on an independant item I'm willing to help what with 30+ years of electronics including design and repair. I found you folks while looking at fixing a small
electric boat for a fellow, and finding a subtancial LACK of 48volt 2HP controllers available.

Chuck