This, sustaining 30mph+ is what does it. My amperage usage quadruples from 28-29mph @ 2.6-2.9 motor amps, into the 15-25+ motor amps and higher at 32-35mph. It’s gotta do with some scientific wind breaking power around 30mph, same dilemma cyclist deal with breaking 30mph.
That mixed with 100 degree days and 170F+ pavement 1.25" away makes all the issues. I can run in winter/spring/autumn on 65 degree days with 6374 just fine. I think it’s a mix of internal and external saturation from ambient temps, more copper would just mean it’s still saturated likely, just with a lower equalibrium temp. If the bigger motors we’re just big enough to lower the temps by 15-20 degrees to hover around 145-155 it would keep the bell magnets far enough away from the 170F point where you start to see demagnetization.
Edit: as you can see 15-25A in the higher duty cycles is really only 700-1000 watts. Ie I can saturate a motor with only 700ish watts. This tells me I need more copper.
If the problem is saturation, that by your description and motor current it isn’t, you would need more iron, not copper, the saturation occurs when the magnetic flux going through the laminations is higher than the material can handle
But for your case more copper and iron is the solution. cooper for lower losse per volume and iron for more thermal mass to smooth out the high power bursts, and also a bigger motor has more surface area to cool down
Some 3D printed fans maybe? Don’t know if you have space for that
100% THIS! Your average 6374 is nowhere near a 3kw motor. All these outrunners were originally designed to run on RC planes, with massive amounts of air pushed into them. And even then, they were never meant to be 3kw sustained. And high heat will permanently destroy the neodymium magnets in these cheap hobby motors far before wires melt.
It is true that an inadequate pack defeats high power motors. Hell, you can have enough parallel cells, but if you build it with single strip nickel, you also fail. But that doesn’t mean the motors are overkill - it means you haven’t built your pack right.
I basically did this with my first autox Datsun too.
Everyone said I should go performance n/a on the stock motor. Okay. Week later I’m pulling a twin turbo w/5speed out of a wrecked Sylvia. Lol
*note. I made @psychotiller build me a 12s for my first esk8 build with 6374x2 so I’m that guy lol
Power does matter, because through power, voltage and current are able to convert to one another. I can take a 10kw motor (and by changing the KV) run it 10000V at 1 amp, or 1 V at 10000 amps. The higher wattage motor will always win because it can always run at a higher current given the same kv.
Or in the case of battery pack build, with 100 18650s I could build a 1s100p pack or a 100s1p pack - same wattage, but very different voltage/amp characteristics.
I currently have 2 builds that both have the same battery system, electronics, wheels and gearing.
Both are street boards with similar decks.
One is running dual Alien HEV 6374/200kv and the other dual Alien HEV 6355/190kv
Both sets of motors tested at 170-175kv so not much difference there.
I have ridden both for some time now and while the 6374s have more torque and are better for climbing hills a low speeds, they have noticeably more drag when coasting/free wheeling than the 6355s so when riding on flat ground, I have to stay on the throttle more with the 6374s and I get better range with the 6355s
The 6374’s are also more noisy running BLDC unsensored.
Bottom line, I much prefer the 6355s for all around street riding.
I thought you gain mechanical advantage over a smaller motor even if the power is the same.
I went from dual 6355 to dual 6374 with the same battery 10s3p and VescX and I did feel a noticeable increase in torque. I do weigh almost double what the average rider weighs though.
The way i mount my motors i can literally have dual motors of any size. While i am running dual 6374 at the moment, what larger options are out there? I suppose i should just google 8084 and see what comes up? I’m running 10s at the moment, so i guess find anything with 190kv?
I suspect this is the case. It shows up in other hobbies as well. In 3d printing, there’s a huge camp of people that think they need name-brand, hardened linear-rails at $100 a foot on all axes, when in reality some cheapo $3 plastic roller wheels are more than good enough for the application.
A 100 kg rider riding up a 20% grade hill, on a 12s board geared to 40 kmh will theoretically draw roughly 50A. 6374’s are typically “rated” at 70-80A. 5045’s @200 Kv are “rated” to roughly 30A.
Some of us are heavier, climbing steeper hills, or riding at speeds where aerodynamic drag is even more taxing than hill-climbing, but most of us are probably fine running dual 5045’s (or a single 6374, which should be more torquey than dual 5045’s).
You should see me on my R2, the rear motors and Trucks get so hot you can’t touch them but on the other hand I can ride my dual 6374 board and my motors barely get warm unless im riding consistently over 30mph, I’m adding more copper and iron to my set up but instead of bigger motors I’m going with more motors. Quad 6374 should feel pretty great. I’m going on a trip next week but when I get back my project will see some real progress
Yeah it’s heavy I did a test mount with just trucks motors and mounts and wheels no enclosure, battery or esc and it felt really heavy but it’s okay I plan to ride it not carry it lol.
Not diagonally it’s on TB 218 trucks using TB prototype reverse mounts, It’s 4wd.
Anyone know if R2 is using higher temperature epoxy and wire insulation enamel? There’s only so much heat you can pipe through an 8mm steel axle, I imagine they have to be employing some other strategies to manage the heat in addition?
Sorry, was not clear enough, was talking about what heats up a motor, the power going through doesn’t matter, the main losses are proportional to current, mainly copper loss in the windings loss and iron loss in the stator, the latter also function of ERPM
so I’m that guy lol
