-I have tried hub motors with high Kv, 130Kv and maybe is true if you are at full speed or close to that but at lower speed they feed so much current that the range was getting less than 1/2 compare to the same motor at 75Kv.
-To get a lower resistance do you think the best approach is to use thicker wires? Also change material might helps but I only saw copper be used for this purpose.
true about the sag, indeed it could have help as well
There’s silver! Not worth it. Generally a fat wire will fill the stator slot better and less resistance and also transfer heat out better but not always. And if spinning really fast eddies will be produced in winding and skin effect and then thin wires are better spinning faster than we do really.
I guess factories use rather thin wires because easier to handle for the machine
Yes. Rcplane guys rewind stock motors with fat wires and get better performance. Besides resistance if the coils are nicely laid the inductance is increased. The tangle of wrapped teeth from factories has less inductance for 9 turns than well laid coils. They might even need to do another turn because of this then ultimately more resistance.
The motors are all delta terminated too as it’s easier but it’s two current paths as apposed to wye and voltage difference will be made between the two if not identical coils and inductance. A loss
Damn so they are all doing in the opposite direction for us. Well all except you of course 
What do you think is a good resistance achivable for a let’s say a 6354 or 6374 motor around 150Kv? Because hte one I have are rather low already. At least for what I have seen. Do not know about inductance. I have the tool but rarely measured if not for checking shorts.
And possibly u. Hoping u rewind one and compare.
Lately wondering how the increased heat in the windings and subsequent increase in resistance and inductance effects the commutation timing. Maybe best to increase the inputs on esc anticipating higher heat. An easy test to see how effects eff. One day.
U got an IR meter! Nice. I have no good guess on what low resistance would be possible. Great challenge though. There’s calculators out there to tell what wire size will work and do the required kv but find safer to just try. And then no one is winding lrk winding which if u have the room, as most standard out runners do, …bet u could get at least 25% cooler running and smoother. Lrk n wye. Super simple winding too.
I have some stators around. I could try. Need to find decent copper wire size. Is there a specific type? Since it needs to be coated outside. I guess is called in a certain way. enamel coated copper?
https://sinuss.nl/zoeken?keyword=enamel here there are several gauges
Magnet wire. I use double build w thicker insulation but whatever. Do get the 200c rated stuff. And do get some thin high heat epoxy to pin it down. Omega brand is small n easy
With lrk u can’t go wrong as u wind every other tooth. U can wind with super thin wire first to both practice the wind and also then run it on bldc tool and see if the kv u want and right amount of turns. Then go for that amount of turns with the fattest u can fit
Thanks! Maybe one day. I would like to rewind some motor and see if I get better output from them. Of course need to run some simulation to ket a decent Kv approximation.
That’s a good advice!
If I had to do it, I’d go for a small mount where the motor drives a roller through a belt or 25H chain, and the roller drives the wheel through friction.
The roller could be a Urethane wheel, or a printed part. Anything really would be better than the motor can.
That opens you a whole world of options, where you can tweak the gearing to match your motor efficient range to your desired speed and torque.
@rey8801 Easy to figure kv u want w the thin winding first
The op…the standard out runner only has bearings supporting on one side and a friction drive will likely ruin the bearings r motor. There’s a couple motors where the rotor is supported by bearings on both sides out there forget the models
true. for hub or DD is normal, but for out runners I always found one side only supported. Had to add second bigger bearing to make DD. I have been recently to a conference and there was some startups engineer oriented. They were presenting a nice concept for electric motors. I have read already about it but was nice to see. They are using the stator as magnetic element and the whole can as steel part. In this way they said efficiency is way higher and the electromagnetic field generated is more organised compare to classical brushless motors.
Exactly, you decrease Kv by increasing the number of turns, you have to reduce the wire diameter to be able to have more turns, so by halving the Kv the resistance goes up by 4, the torque doubles for the same current, and the losses multiplies by 4
But if you feed half the current, you will have the same torque with the same losses
For a given motor design and amount of copper, the motor torque capabilities are independent of Kv, what matters is Km, that represent how much torque a motor can produce for a given unity of power loss, unfortunately nobody publish this number since it would be clear what motors are good and which ones are junk, so the whole misunderstanding of Kv got spread out
But the bigger problem is @Howiep is the VESC poor tracking at low speeds, same problem I’m facing in my similar setup, the situation you want the most torque, that is on really steep hills, is the one VESC fails to deliver
Funny to read this today, this morning I ordered 1lb of 20 awg 200c magnet wire.
I’ll be rewinding crappy skullboard hubs LRK wye
Following another forum users guide, shooting for 80kv with 3*12 turns
skull motors uses 105mm wheels no? Maybe stay around 65-70Kv is a better bet. PLease post updates. It’s super interesting. How did you come up with the 20awg?
This is good stuff, thanks for adding color.
Are you looking at alternate ESCs?
Wow I posted, went to bed, and woke up to a whole conversation!
Fair enough, but I am still looking to increase motor size over the 6354 (which weights about 600g). Also looking for a higher quality motor that can more efficiently turn those amps into motion.
I’m looking for this setup to provide about 50% of the power, so any motor that works well as an esk8 dual setup should work well enough I think.
That’s a shame - I hadn’t heard that before. Anyone got any tips on settings to make it run more efficiently at these low speeds? Also - details of your build?
I’m now supporting the other end of my motor with a pillow block bearing for ease of mounting. I’m confident I could rig something like this up for a different motor. But shouldn’t need to for a hub/DD motor.
@hummieee Did you ever make any smaller motors like what I’m looking for?
Not at the moment, but I’m gathering some equipment to start making some tests on motors and actually rating them, to put to the side all the marketing that comes with them, I want to figure out how much they can actually handle in a bunch of situations, everything done in the bench so its consistent
In the future I want to build a inertia dynamometer, this would make possible to plot a efficiency curve and quantify how bad is the torque at low speeds, if sensors or encoders help, and a bunch of other cool stuff
@Howiep sure, take a look here
One thing that may help according to @mishrasubhransu is to set it up using sensors and set a sensorless ERPM higher than the default value, the motor I’m using doesn’t have sensors so I can’t test that
maybe that motor has a bearing already on both sides of the rotor. I think it might. the often missing bearing support is on the shaft end. I don’t think the bearing you added is going to support the rotor.
I might have some motor that could work but best you get the outrunner from hobbyking or somewhere with bearings on both sides.
I thought a pillow block was for exactly this type of application?