Hey guys - i want to understand why my DV6s is reaching 92% duty cycle on 51kmh/31mph. The motor current is low, and by the gearing setup i should be able to go crazy 81kph/50mph…i am trying to understand the RPM logged as it seems high (maybe it’s part of the reason why).
Build info:
Proto - DV6s - 12s5p (Samsung 50s) - 8’’ AT - 18T/62T gear - Motor 6389 190kv Lacroix
Vesc settings: FOC Sensored / Motor current max 70a, Brake -70a, Bat Max: 100a
Print snippet:
Full log:
thanks!
More info:
With no load, speed is 50kmh as well with 32000rpm (minnie data).
It seems its reaching ERPM limit, but 32k from Minnie doesnt make sense…only if is summing up both motors ERPM*motor pole pairs which would give us around 112k ERPM. Limit is 100k ERPM.
@janpom - can you pls explain how RPM on minnie is calculated? Thank you.
The “RPM” is actually ERPM. We’re aware this is confusing and we want to do something about it. We just didn’t get to it yet.
Thanks for the fast answer.
So: 32000ERPM / 7 pole pairs = 4571 rpm.
This doesnt make any sense…too low erpm to limit anything. If this number is correct, my motor Kv would be:
4571 rpm / 47v = 97kv.
Anyone has any idea of whats os going on?
Do you have the correct settings on the vesc? You have to put these settings on the vesc additional info tab. Do it for both escs and check the speed with the vesc tool
yes, all settings are there. ERPM comes directly from readings without any convertion from setup.
I am trying to understand why erpm is maxing out near 32k. But difficult to test with no load configs. Any ideas is appriciated.
EDIT: charging the board i can now get to 34k ERPM with no load.
These motors come in 90kv,190kv and 130kv In Stock Brushless 6396 Sealed Motor 10mm Shaft Sensored 170/190KV Wit – Maytech.cn--Maytech official website
Maybe you have the 90kv?
What is your duty cycle current limit start? Also try to do a motor detection from the foc tab
yeahhhh - that would make completelly sense being 90kv, but as far as i know, Lacroix motors didnt used to come with 90kv. @Flashgod224 sold me these ones that supposed to be with 190kv.
Duty cycle limit is default, 95%
This is just to say your math looks mostly correct to me.
Technically, the voltage is 47.9V and you should also take the 92% duty cycle into account, so:
4571 / 47.9 / 0.92 = 103.7 kv
Not a significant difference though.
Thanks guys, this all makes sense now - i though i was missing something when doing the math.
I bought these motor from Charles, @Flashgod224
@Flashgod224 - do you know what hapenned? You sold me a 90kv-100kv motor, instead of 190kv
lacroix 12s boards did use 190kv motors that looked like this.
it’s possible however these are the motors they sold with their 18s supersport versions. which were lower. (maybe 138kv?? )
good point, Its a possibility, but the numbers shows around 100kv…maybe this one they were testing internaly but never went to the market…idk.
