I just wanted to post a follow up here because I bought a whole bunch of metal and nylon
gears from keywin about 6 months ago, but I've never had to use them. I originally bought
them because I was getting the motor too hot when running it with the 2nd size up
Infineon controller 30a/600w jobby. Ended up smoking the motor and melting the gears
a bit running it with 40v and 60v Can Tire Yardworks battery packs.
I ended up buying a new motor and switching back to the 20a/350w little controller.
I've been running this now at 40v and 60v for over six months now without any problems
at all, pulling a trailer + 5 year old + car parts + much ruthless hill torture (to really test it)
Its really quick at 60v. Should be plenty of power for most people.
If you're looking for a safe setup without overheating the motor or controller, I'd say
don't try to push it more than the above. I was even too lazy to use a fuse and have
not had any problems. But you really should use a fuse - it might have saved my little
controller a few weeks ago when I accidentally hooked up 4 20v Yardworks batteries
in series = +80v - don't ask. Hopefully I just have to put a new 63v cap in that blew.
But a fuse might have avoided any damage in the first place.
Anyway, no gear problems at all in 6 months at 40v and 60v with the little controller.
Maybe I'll use the gears if I do some maintenance on the motors in a year or two.
edit: I think Keywin is suggesting limiting to 48v battery packs for this controller now.
My posts re opening the Bafangs and other testing were here:
http://endless-sphere.com/forums/viewtopic.php?f=2&t=9969
http://endless-sphere.com/forums/viewtopic.php?f=2&t=10094