ZeroEm wrote: ↑
Dec 03 2021 7:26am
Yes, they are small. Next time you do a Grin order have them throw in a thermistor for $3. I ordered one the first time it's on a wire then later one to solider to the existing wire.
Thanks for confirming! I'll test them today and maybe open the motor up this weekend.
I hate clicking the submit button on Grin orders because there's always something I think of afterwards that I forgot, that only makes sense to get with other stuff due to shipping.
Even though the 24" rim is arriving soon, I'm rethinking whether to change it out now, or try the 26" for a while; after doing some comparisons on the simulator on torque and acceleration between the two. I'm also beginning some research on some type of ghetto heat sinking options, so may spend some time getting some baseline measurements, then add heat sinks and testing again. The available hub sinks are too conspicuous for my bike, so I want to test other solutions that don't stand out as much. I never liked thermodynamics in school, but having a real world application should make it more interesting.
EDIT: Here's what I ordered for my heat sink experiment. The height of the heat sinks is 10mm, so barely above the lip on the hub motor where the spokes are anchored. That way, from the side, they won't be noticeable. They may not have the same cooling ability of hubsinks, but they look like they will increase the surface area by about four times or more, so still should help a bit. Testing will prove whether that's true or not.
https://www.amazon.com/dp/B07PDPL371?ps ... yp_imgToDp
I'll attach them with thermal glue (not epoxy), so I can remove them if I need to change a spoke, etc. I also order some thermal tape, which I will use some of around the perimeter, to keep the heat sinks in place, since the glue takes 24 hours to cure.
Here's are loop around the neighborhood that sometimes use when I'm just going for a short ride. It's only 5.5 miles. Nice in the evening because of the sunset. I go clockwise on the loop, or left to right on the graph. I'll use this for testing the temps of the Leaf motor, initially doing the loop in the same direction, but later in reverse, since then, the initial climb will be a decent sustained workout for the motor. Then later, repeat with the heat sinks.
Every time I take my bike offroad, I remember how fun it is. I guess I don't do it enough. I charged it up this morning and did a quick 10 mile ride on the dirt trails, but couldn't help thinking about whether the Leaf motor will perform as well on these hills. I rode over to the hill from my test loop approaching from the bottom (reverse direction), but taking a dirt paths that parallel the road. It's only 15% average, but several 20%+ sections along the way. I pedaled hard to keep the watts at around 3kW, but did hit 4.8kW a couple of times; but with that, the motor stayed luke warm. Playing with the simulator, it looks like the Leaf will perform equally as well or maybe slightly more efficient under the same conditions, so hoping to not be disappointed.
These trails are fun to climb and descend. Some parts are steep even on foot, but the motor has plenty of grunt when it gets enough amps.
This part of the dirt trail starts at 200ft up to about 500ft, then I take the road for the last 300ft climb.
The road is off to the right of the transmission tower, but crosses between the two parallel towers at the top.
Looks like a steady slope, but there's actually several flat and steep sections. I ride up this trail in 5th gear, so 46T chainring and 15T cog out back, so with the motor I can keep up a decent pace while climbing.
Even though all the parts are in now and waiting, but it's hard to work on the upgrade while the weather is still nice enough to ride in.
EDIT 12-9-21: The rim arrived and ERD is measuring 488mm. Online specs vary between 485mm and 488mm, so seems right. I'm getting 140mm to 140.5mm spoke length, depending on which online calculator I use. Grin calculator calculates the shortest. Seems like 140.5mm should work.
The rim looks good, so now I'm back to finalizing a tire decision. The decision has gone from whether to switch to the 24" rim, but when.
EDIT: 12/19/21 Well the 24x3 tire came in yesterday along with the rim tap. I have everything here now, so nothing but laziness is in between now and having the wheel laced and mounted. I mounted the tire in the rim to try to motivate me. On this rim, inflated, it measures 25.125" in diameter. I was worried a little about clearance if it came closer to 26", but no problem now. Looks decently beefy, and has a good rounded profile, so probably predictable cornering.