Alien 450A 4-24S Sport2 Car-72 mosfet ESC HV problem

[yannkibongui]

Hello, I hope I'm not in the wrong place to post my problem...
[youtube]aTSRcALHnw8[/youtube]
The first part of the video show the motor behaviour I want to have, a smooth start. And the second what I get with mine : I can't start the car smoothly : the motor just "shake" and stop or it start fast, making the wheel burning out or wheelie.
I have a 4 poles leopard hobby 5692 540kv motor and an Alien 450A 4-24S Sport2 Car-72 mosfet HV esc all of this is poered by a 12s lipo, sometimes 6s, or 18s.
I set the timing motor to 8°, tested with 2° to 17° this is the same :/ What would you change ?

 

[Hillhater]

If you want 20 amp type performance, why are you using a 450 A ESC ?

 

[yannkibongui]

I wanted a HV esc to be able to reach big speeds using 12s to 20s batteries.
Bought the 100a version and it just died, well it was a mistake... So for safety reasons I bought the biggest one.
I just don't understand why it is not smooth at all when the motor starts, when it starts... Any advices or info on the settings to play with to solve the problem ?

 

[nieles]

to get better acceleration control, you want torque control instead of speed control for the ESC (not possible with your controller i think)

 

[yannkibongui]

I have this settings :
1. Reverse: On/Off. ON means forward and reverse mode, Off means forward only mode.
2. Timing： 0°、1°、2°、3°、4°、5°、6°……30°。
3. Frequency: 8KHz, 16 KHz, 32 KHz.
4. Acceleration： Soft / Medium / Hard。
5. Accumulator type：NiCd/NiMh、 Li-Ion/Li-Pol、LiFe。
6. NiCd/NiMH CUTOFF：Min、0.4V、0.5V、0.6V、0.7V、0.8V、0.9V、1.0V。Min means
no cut off.
7. Cell Counts:
Auto,2S,3S,4S,5S,6S,7S,8S,9S,10S,11S,12S,16S,17S,18S,19S,20S,21S,22S,23S,24S.
8. LiIo/Pol LVC cut off voltage per cell：2.0V、2.1V、2.2V、2.3V、2.4V、2.5V、2.6V、
2.7V、2.8V、2.9V、3.0V、3.1V、3.2V、3.3V、3.4V、3.5V、3.6V。
9. LiFe LVC cut off voltage per cell： 2.2V、2.3V、2.4V、2.5V、2.6V、2.7V、2.8V
10. LVC cut off type：：Slow Cut off、Hard Cut off。
11. Throttle curve: Logarithmical、Linear、Exponential。
12. ABS brake: Off(0%),10%,20%,30%,40%,50%,60%70%,80%,90%,100%.
13. Power limited forward: No limited,75%limited,50%limited,25%limited.
14. Power limited reverse: No limited,75%limited,50%limited,25%limited.
15. FWD to REV Delay time: 0.25S,0.5S,0.75S,1S,2S,3S,5S.
16. Forward point：Auto、fixed 1.7mS、fixed 1.8mS、fixed 1.9mS、fixed 2.0mS
17. Reverse point：Auto、fixed 1.0mS、fixed 1.1mS、fixed 1.2mS、fixed 1.3mS。
18. Timing monitor: ON, Off. ON means when ESC ready and the throttle in neutral, the
motor will beep different times according to the timing of the motor.
19.start power:
Auto,5%,10%,15%,20%,25%,30%,35%,40%,45%,50%,55%,60%,65%,70%,75%,80
%,85%,90%,95%,100%. Usually the default value ”auto” is ok, but if the motor startup
is too violent or too powerless, you can adjust the value, you can from 5% begin, then
increase the start power percent, till the motor startup performance is good.

Hum, setting up the startpower to 40% and going back to 8°, it seems to be a bit better, less wheelie, but the motor continue to shake and don't start the half of the time... This is the main problem, I'll add a wheelie bar so if it starts quick, no problem, the fact is that then I can slowdown without a problem.

 

[nieles]

Yes, this startup behaviour is 'normal' for Chinese sensorless controllers.. That it is stuttering a bit. The reason for this is, the controller is figuring out what the rotor position is without any information. If you want smoother startup, you need a more sophisticated sensorless controller, or a motor and controller with hall sensor feedback

 

[nieles]

Try the most soft configuration there is, and work your way up.

So:

Timing: 0 deg
Acceleration: soft
Startup power: 5%

Also going to a exponential throttle curve will get you more low throttle resolution an less high throttle resolution

 

[yannkibongui]

Your advices have been useful
Acceleration to soft, throttle curves to exponential almost solved the problem, the car start each time now.
5% is too low, the car begin to start well at 25%, So I set it to 100% and it's just fine. This is the same for the timing degree, I let it to 8° and it's ok.
I said almost because I just have to push the throttle to about 25% to start the car and then going back to 5% to let it roll at the lower speed, so knowing that, it is not perfect but perfectly usable Many thanks !!!!

Do you know what high end esc capable of 20s-24s are available in the market ? I will possibly mount a second rc camera car with a much more powerful motor a tp performance 5860 6Y 500 kv.
Many thanks

 

[nieles]

you might want to check out the VESC project. vedder, a forum member designed a controller from scratch.

the initial thread:
https://endless-sphere.com/forums/viewtopic.php?f=35&t=63540&hilit=vesc

his site:
http://vedder.se/2015/01/vesc-open-source-esc/

also several people are selling them here on the forum.

 

[yannkibongui]

Thanks, I'll check that.