i’m sure we’ve all read through this already: https://www.electric-skateboard.builders/t/choosing-the-right-motor-kv-for-the-vesc/3125
i’m still conflicted on whether a 190kv motor would be ok for a 12s pack? or drop down to 170kv?
Technically you can use a 190kv if you limit the ERPM L, but get 170kv if available.
We use 12S with 190KV and have no issues. As JLabs mentioned just set ERPM to -60/60k and uncheck the apply negative torque option. You can always down gear to 13/36 or 16/40 as well.
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got ya, not sure where but i read the erpm limitation doesn’t just limit the erpm, but the power just drops off? that would be a bit alarming, especially at full speed.
anyway, @torqueboards i’m going to place the 218mm trucks on order now and if i include two 6355 190kv motors in the same order, can you ship them together? i’m in no rush to get them, just putting stuff together for next build.
@thisguyhere - Yeah, sure. We’ll combine them.
Unless, you plan on going 30-35mph… I don’t think you’ll hit the ERPM limit. I haven’t hit. Maybe someone has more info on that.
yea true, i’m already in full freak out mode when it gets to like 20mph so this shouldn’t be an issue.
cool, you should see an order come through in a bit.
thanks!
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Yea from what I’ve heard it’s a hard stop. There’s a soft eRPM limit you can configure in app configuration, however.
Whoa doesn’t sound good… Wtf is a hard stop? Like throw u off the board?
Doesn’t unchecking the “use negative torque” box eliminate that?
I guess it would! I never used it before but I’ll have to soon with my 10s 230kv setup.
Still, I would think that hitting the erpm limit while accelerating would at least be like releasing the throttle suddenly which could be enough to throw some riders. I think the best thing to do is to build below the erpm limit and then no worries.
I have a 12s 192kv setup, with 13/36 gearing. It’s worked great for the last 6 months. (Until I blew up my sk3 motor last Saturday but that’s another story haha). The fastest I’ve got it is 30mph, theoretically it should be going 32, but I figure 30 is the fastest I’ll get when I take losses into account. So you should be fine doing 12s 190kv.
@torqueboards, do you think I would be hitting the ERPM limit in that set-up though? My roommate has the same thing just with 16/36 gearing so it should be getting like 35 mph but we’ve only ever got it up to 30 mph. Now I’m wondering if that’s the ERPM of lack of necessary power to hit that speed.
Here’s my possible setup: 10s4p pack VESC 245kv motor 17T motor pulley to 36T wheel pulley
From your guys’ experience, is that a recipe for disaster? Will limiting the ERPM to 60k and unchecking negative torque for my VESC in the BLDC tool protect me from being thrown off my board if I surpass the ERPM limit? In other words, what would happen if I surpassed the limit?
That’s gonna have way too much top speed and not enough low end torque. Your top speed with that set-up would be around 41 mph (if your motor has enough power to get you up to 41 mph).
Why not just do 10s4p, 190kv motor, and 13/36T gearing? That’ll give you a top speed of around 25 mph and lots of low end torque. You could even switch out the 13/36T gearing for 16/36T to go a little faster (around 30 mph).
Unless you’re trying to hit really high top speeds there’s no point in having a 10s battery, 245kv and 17/36T gearing. Most people do 10s or 12s battery, 190kv motor, and then adjust the gearing to get desired top speed.
Ok, thanks for the info. I didn’t think about low end torque. I already had a 245kv motor, but I can buy a 190kv and I’m stuck with a 17/36 ratio right now.
Does it matter which one of these I get? Is there a big advantage to the pricier one? diy-electric-skateboard-kits-parts/electric-skateboard-motor-6355-190kv/
diy-electric-skateboard-kits-parts/motor-6374-190kv-3150w/
No problem. Having 17/36T ratio is fine. One of my boards uses the more inexpensive motor of those two and has 16/36T, so almost the same as yours. It can accelerate fine and climb moderately steep hills, so you should be fine with the cheaper one. The only difference between the two is that the cheaper one is less powerful (2500 watts vs 3150 watts for the more expensive one). You can also buy a 13T pulley to replace the 17T from that same site for something like $15, so you aren’t really stuck with 17/36T if you want low end torque or hill climbing ability.
Better alternative to the $90 diyelectric one, or nah?
I’d say no. That’s the exact motor on my main board. I’ve had a few problems with it, the first is that it doesn’t have a key shaft cut into the motor shaft so you have to file down the shaft and use a set screw as a keyway, I otherwise the drive pulley just slips on the motor shaft. Also it seems to get a lot warmer than the diyelectric one I have on my other board while climbing the same hill, I’m not sure why. And by the time you pay for shipping it’ll be about the same price, as the diyelectric one.
However, it is more powerful and slightly cheaper, so if that’s something you really value then go for it, but in my opinion, if I had to buy a motor all over again, I’d just get the diyelectric one.
This is a good tool to know if you’ll reach the 60k erpm. If you do a lot of downhill riding you might exceed safety limit
keep in mind also you’ll only be fit one 6374 motor per truck.
if later on you want to go dual, it’ll either have to be diagonal, or criss-cross drive.
i ran dual 6374 in diagonal when i started, and even though the power was incredible, it was generally a pain in the ass to maintain.
setting up for a dual rear 6355 setup at the moment.