neptronix wrote: ↑
Apr 12 2018 8:43am
The maximum efficiency point is 333W on 36 volts / 11.1A on this ~230rpm wound motor pictured. I believe that this motor may handle 350-400 watts continuously on 36 volts. 48 volts might put you in 450-500 watt continuous territory in a 26 inch wheel or smaller.
These are just some conservative estimates based on the data sheet.
Keep an eye on those motor temps at 600w. It might be hard to find out where the stator heat is. Measure the temp on both sides of the case and the axle as well. As with most geared motors, if it feels hot on the outside, it's scorching on the inside because the thermal path from the stator to the case on these motors tends to be extremely poor.
That's good info. I'm new to these small hub motors, so I'm not familiar with all of their traits and what to watch for. I should note that while I'm running this motor at 480W max right now (in a 700c wheel), I almost never use full power except for three steep, but relatively short hills. All the other times I'm either using 70% throttle or just 30% throttle. In fact, so far I'd say I'm using 30% throttle about 75-80% of the time I'm using any power, and that's only for about 70% of my total commute. The other 30% of the commute I don't use the motor at all.
When feeling the motor I'd been touching the center of the shell, the inside of the spoke flanges, and the side cover on the brake side. I hadn't thought of checking the axle itself, but that makes great sense. I'll try feeling the axle tomorrow after my commute to see how the temps are right by the cable exit.
Since I'm only using full power for short spurts followed by long periods of very low power or no power at all, I think I'd probably be able to run on 600W, but that may not hold true for everyone. If this motor follows many hub motors, it can probably run reliably on double the rated power, so for most people, this may be a 500W max motor. I'll of course post here if I do anything that cooks this motor.
Also, as far as the noise goes, it seems to be getting better to my ears—I don't think its because I'm getting used to it. I do think the motor has gotten a little quieter, but I only have about 30 miles on it so far. This weekend I'll try to get a video of me riding past the camera at full speed, from a stop, and coasting. That should give you an idea of what it sounds like to others as you pass by them. I'll try to do a second video in a month or so if I notice that the sound levels have continued to go down.