Thank you!
Br
Rikard
This is a really interesting approach @Riwi . What propeller are you using?
Kul med att det finns lite svenskar här på forumet också 
Stockholm?
Hej!
Everything is homemade.
Based in Sthlm. Foils outside of Blidö duringthe summer. you?
Cool! I am also living in Stockholm. My foiling will mostly take place at the west coast though. Close to Lysekil.
Här är en till - från Göteborg.
How is the chinese gearbox holding up? Did you manage to get one with a high RPM rating?
is there a reason why you measure the phase amps?
Phase amps equals torque of the motor, but I guess you are interested in the power, which is related to the battery amps (you can have 100A Phase amps but only 1A battery amps).
Hi!
It is also true that the phase current can be higher than the dc-side amps? I wanted to make sure that I don’t fry the motor at an early stage.
Sorry, didnt have coffee before reading. Main reason is to know how many amps are acctually going to the motor.
I have not tried it under load. Yet I am not expecting any wonders. It was quite cheap. But the according to the specs it should be allright.
The current in each motor phase is √3 lower than the current that comes from the battery.
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Ok! that would mean that I’m close to the limit with 35A on the phase today. I will measure on the DC-side next time. We just got hit by snow and ice so it might be a while.
can you explain that?
Phase current can be anything equal or higher than bat current (neglecting losses inside ESC).
You have a brushless motor, it is a syncrone electric motor. You have three phases. You can look at the wikipedia page ‘Three-phase electric power - Wikipedia’ balanced circuit section to see the demonstration. But even energeticaly speaking this makes sense. That s also why esc manufacturers tend to provide smaller wires for the motor phases than for the batteries
i am trying to understand, a 35A on one phase motor, how much will it be on the battery with a Y and DELTA motor, please ?
Can you explain what the voltage difference between 2 phases has to do with the current flow between 2 phases?
You don’t have a static resistance (if you exclude still stand), so how can you determine the current by the voltage?
No, energy delivery can be close to 0 and still you can have 100amp phase current, so battery current ~0 and phase current 100A. Eg. if you hold your motor, much torque, close to 0 movement so 0 energy delivered so batt current ~0 (some heat losses). But torque comes from phase current, so high phase current…
still you have higher phase currents than battery currents…
anything between 0 and 35A, thats what I wanted to say with:
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Sorry to put it that way but I dont think you understand it right.
“No, energy delivery can be close to 0 and still you can have 100amp phase current, so battery current ~0 and phase current 100A. Eg. if you hold your motor, much torque, close to 0 movement so 0 energy delivered so batt current ~0 (some heat losses). But torque comes from phase current, so high phase current…”
Its not because the motor is not turning that the battery does not provide energy to it. For example you can try to block the rotor and put max throttle and I can assure you that the battery current wont be 0. On the contrary, this case is when the current consumption is the biggest i.e low or no rotation speed and huge resistive torque on the motor. Furthermore, energy delivery is related to power delivery so to both voltage and current. You are right when you say that torque from the current in the motor phases.
Theory is one thing, reality something else. I Will muasure both sides next time.
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it has be to battery current, i had the problem with my kid car, the motor stalled to much, i change the battery to a high discharge one, no more stall just heat on the motor
and i had the “same” problem with my small low torque motor on my efoil, it kills the battery
well, read it by yourself:
Depending on dutycycle your ESC acts like a buck converter, so phase amps always >= batt amps. In extreme you have only heating losses as bat amps and torque of phase amps.
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