ok i think I got it now - thanks for your explanation. What I still don’t understand however is how @amf is able to test his setup when he applies 30A battery current. What phase current is he then using (the VESC seems to regulate the input current itself based on the load no?). Also how is @amf doing his tests that he still thinks voltage matters noticeably?
@moderators you might want to put this discussion in its own thread - it has nothing to do with VESC6 but ESC power losses in general.
No problem (if you were thanking me). This is a complex topic.
It’s important the way things are phrased, @amf is not applying 30A battery current, the vesc is pulling 30A from the battery. The phase current at this battery current/voltage depends on many things like motor winding resistance, motor speed (back emf) etc.
What I am assimung about @amf’s test is that he is running a motor at some duty cycle, say 90%. Lets assume at 24V, 90% duty cycle that particular motor, under whatever load it is under has 20A phase current. So if they increase the voltage to 30V and keep the duty cycle the same, the phase current might increase to 25A.
In answer to your other question, the VESC takes a throttle input in some form (analog, PPM, PWM) but it has many different modes to turn that throttle value into output duty cycle. IF you run the VESC in the duty cycle mode, it will turn the throttle directly into duty cycle. So at 50% throttle, you will get 50% duty cycle. On the other hand if you run in Current mode, 50% throttle will turn into 50% of your set motor max current.
The other complication is that in duty cycle mode, you will still have a current limit. So if your throttle is 90%, but you have a motor current limit of 50A, if 90% duty means motor=100A, the VESC will turn down the duty cycle until the motor current=50A.
Similarly if you are running in current mode and you have 90% throttle and current max of 50A, so set current =45A. If 95% duty cycle only gives you motor=20A, there is no way of increasing the motor current.
So maybe @amf is increasing his VESC power(heat) by increasing his input voltage because he is either at a duty cycle limit or a current limit, and increasing the voltage allows either of those to be overcome.
But he said this:
that is why I said he “supplies” 30A as it sounds like he keeps this constant - but in the video the VESC regulates the input current dynamically and keeps the phase current constant.
I am just trying to debunk his mentions of the voltage having an effect on the heat loss in the VESC. Even with the P=I²R formula he still seems to think it is not true.
I suppose the details are important and maybe they have been posted but I didn’t read far enough.
They say
@amf “They put 30a / 48v into the VESC through conditioned power and had a motor drawing max amps running at constant voltage on the other side.”
What is max amps? and at what voltage. The maximum number of amps depends on the motor winding resistance. Absolute worst case is the motor being stationary, and they they will draw hundreds of amps (if you don’t control the duty cycle).
“With efficiency losses, slightly lower than 30 amps.” If it’s slightly lower than 30 amps, its really not max amps or a worst case scenario.
Maybe they mean that in their product, they have the motor current limit set to 30 amps, and so they wanted to test what would happen running at that motor current? And so they or their test place naively thinks that current battery = current motor, but that is a complete misunderstanding.
I think I caught up and found where the problem in understanding started. I should have read it sooner. @amf says this
This test is only valid IF the motor current is controlled. It also doesn’t guarantee a worst case scenario. If you have Battery=48V@30A, but motor current is only 30A, you aren’t testing worst case. You could have Battery=48V@30A and Motor=9V@144A. This is the kind of thing that could happen with a heavy person riding up a large hill.
In the second case, you would have ~20 times more power being dissipated in the VESC. (this is why you would limit the motor current to less than 144A 
)
Yes, or someone riding your product on soft sand … uphill
The motor current was limited to 100a (not 30a) … my mistake … I can see the motor at over 40a in the data I have from the Metr app here under ‘normal’ load, but what you outline is the right principle.
Apologies for the confusion.
Cheers.
@amf, AHH! that makes more sense now. If you have the motor current set at 100A, and you have some way of keeping it at 100A, then you have one way of comparing one controller to another. Do you know how they kept the motor current at 100A? Did they put a large variable load on the motor or was it done using some of the vesc tools like FOC_OPEN_LOOP?
but he just said that only the LIMIT was set to 100A and that the actual load was dynamic (e.g. “40A in metr app”). I still don’t get how they are doing repeatable tests between controllers.
It’s certainly not the way I would do it, using the FOC_OPEN_LOOP like vedder did in his videos is the easiest and best way to compare current handling.
It’s not completely crazy though to have a big motor and load it down so that it always current limits at 100A.
They put a load on the motor as far as I know.
@Maxid They weren’t using the Metr app: I have it here with a prototype.
The VESCs were tested on a bench. It was a commercial test lab inside a large company that makes motors.
Cheers
well according to the results you defend (you say “voltage matters”) the test lab has no credibility to me right now no matter what company it is part of.
But if they did then they should have arrived at the point where the input voltage does not matter no?
Yes I agree with this @Maxid and your other comments. Definitely to do temperature testing it is not necessary to use large input and output powers. Only output current has a real effect on temperature.
However I would say in testing a product like a speed controller, if you are doing engineering testing, it will be important to test at both high voltage and current, input and output to see if there is anything wrong with your design.
Thanks for the advice. I’ll pass it onto the engineers.
Cheers
Provide your proof!
how much it?
Don’t forget, that motor current is always carried by the Fets! Irrespective of battery current… And we sum up the current on the three windings, so they run somehow also in parallel. Not three at the same time, but it is also a factor playing a role.
Has anyone used a Photon remote and receiver setup on BV VESC 6 if so can they post pics of how they connected the receiver to the controller?
Reciever to controller? Binding them?