grin GMAC with 72v??


Local time
1:28 PM
Apr 28, 2022
Does anyone have experience with running a grin GMAC motor on high voltage? On grin's website they list the GMAC as part of a 52V kit. For their high-voltage kits, they have kits built with the the RH212 and the All Axle motor, with 72V controllers. But with their motor simulator you can put the gmac at 72V and it seems to perform well. I know there is at least one person on line, with some youtube vids and some files on reddit who has done 72v (nominal 72v, 84v peak) on the GMAC, so i know it's done but i'm not sure it's recommended.

The deeper story is that i have been really enjoying the high voltage kit with an RH212 that i have on my high-speed low-load recumbent speed deamon, and i'm now looking to upgrade the hub kit on my heavy cargo bike. The thing is the RH212 is a DD hub and is really powerful but it really rips into it's power band at higher speeds 25 - 35 mph), whereas the GMAC has a more trapezoidal power shape, with high torque and power output at low rpm, natural of a geared motor, which it is, relative to direct drive hubs. I'm just wondering with a motor that size, is it permissable, but perhaps not wise to run 72V through such a tiny motor?

I'm going to spend some time searching more through the redit files and other stuff from the few out there who have done this, i just thought i'd ask on the forum here first.