Afterwards, the temperature is practically not rising, staying below 50°C! This is what i wanted! 8 Minutes riding at full throttle with 2300W. It really makes a big difference in the feeling and sensibility compared to the 1800W i got before with my tuned VESC 4.12, because the board is clearly gliding. Now it makes turns rather easily and is sensible for my wheight shifting.
For some reason my TF02 which i use as a battery gauge frozed the values and including battery voltage, so i stopped rather early. At home, after disconnection and reconnection it worked as if nothing ever happened.
Tomorrow i will set the motor current to 100A and try again.
The spike at 1000s is freerunning in air!
Thank you a lot for this controller, it is small, light, has much more power than the best VESC 4 i tuned and solves the problem with a lot of headroom and potential for further optimization. I was very surprised how little there was missing to reach the goal!
Thanks also to Flo, who made the Software for the ESP which transfers data from the VESC via a WLAN into my smartphone, and various tools into this stunt graph. Thank you a lot, i learned a lot of this forum.
At today tests the ESP was not running, i do not recall why. Instead my BMS worked today so we had a rather constant reading on the display of 2.9kW. Speed was slightly higher than yesterday. Emptied 90% of battery capacity and had lots of fun with my son.
Also i used a geo tracker app today, but i am little disappointed of the quality reached. Stated a max speed of 23km/h which i do not believe. I think 18 to 20km/h constant speed is realistic data.
Made some bollard thrust test and altough the VESC always stopped when passing 35kg it was kind of impressive.
In the measurement from yesterday i found some fault code 4 which stands for Abs over current for 0.6s and also today i had some sudden stops. It was dependent on the amount of acceleration. @nickw1881 is it possible to set over 160A abs current with the current firmware and hardware?
ABS max current can now be set up to 190 A. Please keep in mind that the .5 mOhm shunts only sense up to 165A, so if you want to go higher than that you’ll need to turn on high current sampling mode.
Well, somehow the max current cannot be changed. I think it has to be compiled with NO HW LIMITS.
Anyhow, i tested a prop with less pitch, with 100A phase current limit and there were no stops anymore which is a great gain.
My telemetry does not work at the moment, but as the maximum power was 3.4kW in the beginning and went down to 2.9kW in the end i assume it was running near 95% dutycycle. This means the phase current dropped from 100A to 75A by changing the pitch from 8 to 7". The geotracker reports 21km/h maximum velocity and this is very small gain.
@nickw1881
I read the whole topic, and I’m really interested in such a Esc. Do you have some plans, or is the esc still available? I’m at he beginning of building an efoil.
Max
I’m getting 10 of them made right now. If nothing goes wrong, no trade war, nothing is impounded by ICE, no workmanship defects, the assembler doesn’t substitute non-brand crap capacitors, I should have them in hand in about 3 weeks.
They are “public beta” status. I will be selling them with no heat sink for $240 + shipping. That’s less than my cost, but I think a fair price for an untested product. I’ll need feedback on what doesn’t work or what broke. For what it’s worth, they work just fine on the dyno, just not sure about the weird stuff that only happens in the real environment.
I’m working on a heat sink, in case people want something partially enclosed like the ARC200. That will cost extra.
Still not sure the final sale price for this design, probably $350, unless the magical promotional ad campaign fairy comes and makes a really cool promotional ad campaign for kickstarter and I can make them in batches of 1000.
This was with 7" prop. As you can see, the dutycycle is permanent at maximum of 95%. This week i am going to receive 300µohm shunts to avoid shutdowns by overcurrent. Than i will try with 8" prop again with higher current settings, so i hope to build up even more speed and power.
@Alexandre According to Benjamin Vedder, the motor current reported by the VESC is the current used to create the magnetic field. It’s something that comes out of the math guts of the FOC algorithm, and it seems to be pretty close to the sinusoid peak for each phase.
I think about it like this: in a DC load, the voltage all drops across the load as work. Each electron delivers ALL of its potential energy to the load. High pressure on the input side, low pressure on the output side, and the current flow is directly proportional to the load.
In a BLDC motor, the motor creates most of it’s own voltage by spinning, so there isn’t a huge pressure drop from electrons slamming into a wall and losing all their energy. Each electron can only transfer energy equal to the difference between the input voltage (pwm duty x battery) and the motor rpm (motor rpm x kV). Instead, larger numbers of electrons will flow, each doing relatively little work.
So maybe think about the controller as a small accumulator tank: A few high energy electrons slam into the tank from the battery, and large numbers of low energy electrons flow out into the motor. Even when the duty cycle is 100%. That’s about as good as I can understand the physics.
For power analysis, the “Motor current” measurement is useless, unless you know the efficiency of the controller and the power factor of the motor, which is probably dependent on RPM and torque. But I think it does tell you something about how much relative torque you are putting into the motor, and it does tell you if you are exceeding the motor current specification.
It is an interesting plot, as you can see we got overvoltage failure at 18:15:07 , when i triggered the main switch, so the battery is disconnnected in ground path. At 18:15:53 s we have overcurrent reached, the typical announcement of the vesc, when you go too steep.
Thank you , i am new with the foc mode which i will run this year… Didn’t think about this amp"pics" of the motor…
As i was thinking to get the power used by the motor close to the power of the battery in order to stay around a nice torque/trust area ( bigger propeller data will be interesting )
Missing the rpm value on the data for calculating the torque value …
I am trying to get my way around the numbers in order to estimated the best combo pitch/diameter/rpm for my needs
The metr.at tool is just incredible. Therefore, a few questions
1 - Is there another tool on the market that aggregates speed with the real time consumption data (Voltage, current (battery)
2 - can we get instantaneous consumption in WH not averaged (smoothed) on a distance we don’t really know how it has been calculated ? My guestimate would be that the speed is calculated from the derivative of the distance travelled over the last 1 or 2 seconds (from GPS data) which would mean it is the quasi real time speed and consumption which would be a gift.
To compare prop efficiency, we could create a set of indicators:
I propose this first one:
SPUP : Speed Per Unit of Power: kmph reached per consumed power unit (or WH)
= speed (kph) / [ Voltage (V) x Current (Amp)]
Conditions: at identical duty cycles (DC) (could be linearised by a rule of threes even if I am not sure a motor reacts in a linear way)
That’s where the Maytech remote is helpful: 33% DC, 66% DC…
If it is demonstrated that the motor power and Duty Cycle are proportional therefore linear, I propose the SPUP-L
SPUP-L : Linearised Speed Per Unit of Power: kmph reached per consumed power unit (or WH) at any duty cycle.
= speed (kph) x Duty Cycle (%) / [ Voltage (V) x Current (Amp)]
Conditions: none = at any duty cycles (DC)
Xmatic app is worth the try , more worried about the fw update for the new vesc 75/300…
I have set my remote with 2 modes 80 and 100% , will see i just need to finish my board …
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