Starting Tips | Ask Questions | Introductions | Categories

Extended BLDC-TOOL with Watt Control Mode, PPM Cruise Control, individual Throttle-Curve and Android App

I tested the speed control no accelaeration with 250W-limit but it felt weak, maybe it’s not possible to make a law-confirm-board that is viable for commute, sadly.
It felt I pushed the board to about 20 km/h, pushed the button and the board slowed down a bit and I cruise at about 15 km/h or something.

Best thing, it slowed down downhill and kept the speed, that was nice.

I need to increase the watt-limit I think and test again.

So you tested the “PID speed control no acceleration”. Be aware that this mode doesn’t make the board legal in Germany. It was only a test and to be prepared if the law get’s changed. And if you want to output 250 watts then you also can add the efficiency loss by calculating 250 / 0.90 = 277 Watts for 90 % efficieny of the brushless.

You should give the normal “Watt no reverse with brake” control also a try. BTW i run my single drive board with 1600 Watts max and my dual drive with 1200 max Watt each, (so 2400 Watts total).

If you want to compare Watt control against Current control then set the max watt by the this calculation.

Your Max Battery Amps * 3,7V * Battery Cells = Max Watts E.g 30A * 3,7V * 10S = 1110 Watts

But some more tips for “PID speed control no acceleration”. You said that you like that it slows down going downhill. I recommend to switch off breaking in cruise control. You can do that over the advanced tab. Because then it is really nice to carve at cruise control.

Maybe it’s not legal but with no acceleration an the limits 250W at 25km/h it is not a KFZ and so they can’t fuck me over with 1500 Eur and confiscate my board.

I’ll test a few different setting the nect weeks, when the rain stops…

Does it make any difference if I set the watt-limit at “Define-Max-Watt” or at “Max Battery Amps * 3,7V”?
Because when the board is full charged it’s about 41V and empty at 32V, so I guess the “Define-Max-Watt” is more accurate?

Yes it does make a huge difference.
Max Battery Current is the max amps the VESC can draw from the battery. So max watt can’t go higher then the max watt which is allowed to draw from the battery.
So if you have a 10 S battery and set max battery amps to 30 you are allowed to draw maximum 30A * 3,7V * 10S = 1110 Watts.
If you set the max watt value to 1500 Watts in this scenario you also would loose throttle range because when the throttle tells to provide more that 1110 watts the VESC does not allow that.
So i recommend to set a value for max watts below the result of that calculation and not higher than this.

For example on my single drive 10S i have set max battery amps to 50 A which would allow around 1850 watts (50A * 3,7V * 10S = 1850 Watts). But i set max watts to 1600.

1 Like

Maybe i should share how Watt Control feels to me compared to Current Control.

With Watt Control it feels like i have have a direct connection between my finger and the boards power. And at higher speeds it is very controllable which makes carving nice, because i can use the full throttle range.

Current control feels to me like if there is some chewing gum between my finger and the trigger. And at higher speeds it brings you easily out of balance when you have a powerful setup because of the loss of throttle range.

1 Like

I implemented a parametric mapping for my teensy controller. First I tried bezier splines because in fact you only have 2 parameters to choose, the normalized gradient at the beginning an at the end. I ended up using an exponential function because there is only one parameter left tho choose, the exponent:

#define YAchseExpAccel (float)              2.0 // Beschleunigungsfunktion 1 linear, 2 quadratisch
#define YAchseExpBrake (float)              1.0 // Bremsfunktion 1 linear, 2 quadratisch

But more important for the user experience was the possibility to choose different exponents for acceleration and braking. So you might consider this too.

First hard fight i have to do is adding a graph in BLDC-Tool which shows the throttle curve. Took a while to understand the Framework. But finally i have the first results. Still far from finished but it seems i am getting there.


@Ackmaniac quick question, will your 3 point PPM work with current control or does it only work in watt mode?

It could also work in Current control. But i think it would make it even less responsive. But i will try to implement it for both.

Oh i mean, if the min max and center will work in currenbt control.

Yes it does. Works for every mode.

Enough work for today.


Coming back to the firmware 4.7 question. If you don’t mind, I would like to compile your firmware extensions for my HW4.7 - are you willing to supply the sources? Would be great, even if I have the chance to spoil my HW once again :persevere:

Let me first finish my throttle curve adjustment and then i will make my code public so that you can compile your own firmware.


Wow, great work.
now, who wants to make an PID acceleration control mode? :laughing:

The user interface to control the throttle curve got much better than expected and is really easy to understand. I am really surprised.


Ackmaniac, you’re a genius !
What an amazing job !

You should definitely share it with Vedder.
It will be a shame to loose all this great job with VESC Tool and VESC 6. :wink:

And for that you guys need to test it. Because if the community likes it then i think Benjamin will think about it.

I start to feel bad for not giving this a shot. Once my battery is finished I might try it - but that will take some time (and it’s winter now :frowning: )

Same for me mate !
I run from issue to issue with my builds.
Once it won’t take fire anymore I’ll be more than pleased to test your version ! :smile: