I have been running a 245kv SK3 on 8s for a while, and thought it did pretty ok. However, the torque really wasn’t quite enough for me. Eventually, my lipos gave out, and I decided to build a 10s4p pack with Samsung 25rs to try and get a little more umph. A friend of mine helped me set it up, and was kind enough to let me borrow his spot welder.
My question is, as long as I limit my ERPM to 60K, will my vesc be ok? Or should I just get a new motor? I only realized this might be an issue after I built the pack. Doh!
I have my eyes on a 6374 sk3, would be a blast! But, if it is unnecessary to upgrade, I’d like to keep my current motor. What do you guys think?
I went from 6S Car ESC on a 245kv to 10S VESC - despite changing gearing and changing VESC settings could not get the same performance as original set up. Changed to 6374 192kv and all good.
I’m using 10S lipo with 240kv alien motor and limited the erpm 60k, I havn’t had any vesc failures,
when i first built it i hadn’t read about the erpm and used it without the limit, even then i had no failures riding it around my street.
to reach the 60k erpm limit with 15T - 36T gearing and 80mm wheels you have to go over 33mph, i’m guessing most people who got failures from this were spinning the motor with no load or had a higher gearing ratio.
but i haven’t tried any other motors yet so a lower kv may be better in someway
What do you mean by performance? I can’t see how you could get near the same amount of speed/torque out of a 6S
Very interesting. I wonder why that is.[quote=“LukeL, post:4, topic:18019”]
I’m using 10S lipo with 240kv alien motor and limited the erpm 60k, I havn’t had any vesc failures,
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Thanks for the reply, sounds like you’ve had some sucess. As long as I limit my ERPM I shouldn’t get any no load failures, right?
Yeah the setting should stop any chance of the erpm causing a failure.
I also use the soft erpm limits on the ppm tab to slow down acceleration as you approach 60k. The fastest I’ve gone on my board is 24.8mph so this probably isn’t a concern anyway.
6S to 10S with same motor SK3 245
6S was ESC - 10S VESC
I did not get any failures - just performance was not as good as with 10S.
Power was the issue, lack of acceleration, changed to 192 kv motor and bingo. Good acceleration and good top speed.
Maybe it was your motor max amp setting (on the low side). This plays a huge role in performance in the low speed torque. Since a Car ESC (or whatever you were using) likely doesn’t limit motor current, this might be why you had worse performance from the VESC.
yes, that’s correct - I like cake a beer, so even with increasing max amps it wasn’t enough.
I like the way an ESC can take abuse without complaining and am tempted to go back to the dark side for a 12S set up but am holding off until VESC 6 has been trialled.
@Alanhunt123 here’s the best thread we have on the subject, compliments of @chaka. TLDR: Your VESC and motor will be fine as long as the 60K RPM threshold is not exceeded. You would likely experience an increase in available torque with a lower KV motor, at the cost of a lower top speed of course. If it were me, I’d keep the motor you’ve got. If you upgrade in the future you might consider 192kv.
I feel that the VESC the ERPM should be programmed into VESC firmware. Maybe there are some scenarios where you’d want to exceed it, but it seems to just cause problems for folks. I had a DRV fault once during bench testing. Seems like an avoidable problem!
I have only put about 10 miles on my build, but its 10s dual vesc sk3 6364 245kv, erpm limit 60k, and I have had good torque and no vesc issues so far.
It has been said that lower KV and Larger motors like the 6374 produce more torque and is usually the best choice for a single drive.
6355 190kv motors work well on 10s in a dual drive.
I have found( thanks to @Hummie who led me in this direction) that increasing your motor max amps in the bldc tool will also increase power/torque especially at lower speeds. I got noticeable improvement on my dual drive with Vescs and 6355 190kv motors by just uping the max motor amps from 60 to 80, with no ill side affects caused to the Vescs or motors.
I’ve tried using really low ERPM limits, and it seems to work well. For example, I limit my reverse ERPM to 5000 to avoid backing up too fast. It never gets jittery around the limit, so I may end up limiting my forward ERPM to something like 50k-55k, since I don’t want to go faster than that anyways. In fact, when I first tested my VESC on 8S, I limited to 40K, and never experienced any issues, the soft cutoff worked like magic!
I have my motor max set to 70, the recommended max amp stated on Hobbyking, but my motor stays pretty cool. I’ll try bumping up to 80, should give a nice boost! We’ll see if my belt can hold out… just upgraded to a steel pulley.
The information your sharing about the erpm limit is very good. Maybe I’ve missed something along the way but this thread is the first I’ve seen where someone actually ran tests with erpm limiting and was able to offer conclusive results. This kind of knowledge is a real game changer.
As for the motor max amps, my motors are rated for 80 amps. I have run the motor max as high as 100a
With just a little warming while driving hard uphill.
At 80a motor max, they barely even get warm.
The person who got me to experiment with this setting is running his at 200a in FOC mode!
100a felt like more power than I needed so I backed it down to 80a
Great to hear! I’m always trying to get more involved in the E-Sk8 community.
That’s insane! Must be a beast with tons of startup torque! This type of setup must really benefit from having a sensored motor. I have yet to venture into the sensored territory, but will likely pick one up if/when my current motor dies.
I don’t think he’s running sensor motors. Just FOC mode in the Vesc.
And you hit the nail right on the head.
He said it gave him lots of startup torque