neptronix wrote:Some BLDC motors have very broad torque and efficiency bands. Proper controller tuning can make things better. The thinner the laminations, the more you run them at an ideal load, the better, as well.
A transmission continuously gives you an efficiency hit. If you are climbing ridiculously steep things though, they start to make sense. The kind of terrain you need to conquer will determine whether a fixed gear setup that is slightly oversized to the point where it maintains thermal stasis, or transmission.
That being said, what kind of offroading are you dealing with?
Grades that are marginal for my traction. My build has only 750 watts, and I therefore need the reduction. And I won't be messing with motor construction or hot rodding my controller. I already had the Nuvnci 171 ~3.5/1 reduction trans, and wanted to exploit it, Agree on combined efficiency hits. ~15% trans hit. ~25% motor hit (would be twice as bad without transmission), and assorted jackshaft and chain losses. Now, I want to add a hydraulic motor/pump with weight and more drag! I agree that it sounds silly but my only defense is that I have ridden my current config enough to know how muly it is, and I think the drive train can handle 2wd.
Thx for taking the time to discuss, neptronix,,