Battery Amps, Motor Amps and Duty Cycle... Please Explain

link me the drama i missed out on, I can’t sleep :black_heart: :popcorn: :upside_down_face:

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Volts x amps = watts

Simplified explination:

In a motor: Amp in a motor generates torque. Voltage is speed (RPM). RPM is based on kV. For ex. a 200kV motor will spin at 200 RPMs if given 1 volt (under ideal conditions)

More motor amps = more torque. As motor rpm increases, voltage increases. If you set 80A to a motor, and you start from a standstill and go full throttle, as the motor just starts to spin, the motor will only “see” maybe 1V, but full 80A. AKA it is drawing 80W. As it picks up speed, it’s voltage increases, so does it’s total power draw.

This continues until the ESC hits the battery amp setting. Say the battery is at 40V with current set to 20A, this means at 800W (40 x 20), the motor side will start dropping amps. So when the motor goes past 10V, the 80A will start dropping, until it is at full RPMs of 40V from the battery and only drawing 20A.

Realistically it’s not quite like that, but fundamentally that is how it adds up.

Now voltage alone does not determine top speed, total watts also play a role. If you have plenty of watts, but not enough volts, then your motor caps out at it’s max RPM and that is your top speed. On the other side, if your motor has significant voltage but you cannot give it enough amps, there is not enough total power (watts) to overcome resistance like wind, and now that is what limits your top speed.

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Rake your own muck, friendo.

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Oh…soooooo you must totally still have an awesome relationship with the guy.
Rip to info

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Very well put thankyou for simpleton translation

I have shared the historical vomit many times on the forum. Seek and ye shall find.

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Great 'splaining. Thanks for that.

Even simpler, consider volts a big tank of water (electrical pressure?) and amps how quickly you can flow that water. Your motors in this case are the faucet.

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Perfect assist! Always has been the way I’ve been taught in intro ee classes. I was trying to analogize an esc. I guess that would be the control system of a hydroelectric dam? Not sure if that really applies.

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I like your description and would not change a thing about it.
analogies are hard with tech and in general i attempt to avoid if possible. as you are well aware from experience - when introducing a topic such as energy it’s near impossible though

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More like 8V :P.
Most kids in robotics don’t even understand this, they’re so used to brushed shit they used in FRC and other competitions in high school that they think motor current == battery current, which is NOT the case.
The reason for this is because the controller actually turns the motor on for a short period of time and then off. The current that flows through the motor stays there because inductors resist changes in current.

God, those pieces of absolute shit controllers didn’t even have synchronous rectification!

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wait what happened??
Deckoz 2.0?

Not on that scale, but equally retarded.

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So which amps gives burn outs?

All of the amps

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The more amps :+1:

20200417_093717

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Soooo I had a very good question related to phase amps and went doing some reading on ES !

From my understanding Motor phase amp = torque from zero to mid speed and Battery amp = torque from mid to top speed

So burnout comes from phase amps. Also the bigger the battery amps, the easier it is to burst phase amps.

Nothing new under the sun however I needed a refresh : do we agree that 100% of the phase current go as positive and negative through 2 phases while the last one stands still during cycle, and position alternate/overlap continuously ?

So the ESC effectively burst phase current through each phase (while another phase returns the burst to ESC) ?

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There is 1 concise Question that I must realize the answer to if it is the last thing I do! If anyone can pull this Sword out of the proverbial Stone, If anyone can tell me the answer to this question, You are truly the ESK8 Riddle Master, and I will forever be grateful for your Supreme Intellectual Excellence!!!

THE QUESTION:
If I use a “FOC” ESC to control 1 Hub Motor rated at 80 amps and 50 volts maximum, and I have a 50 volt Max Battery pack, how many Amps Maximum (Surge) should my Battery pack be able to supply so that my Hub Motor will have all the power it needs for its maximum performance?

It would be very helpful if you provided your battery specs.