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Old 06-26-2010, 01:49 AM   #991
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So why would one need an expensive ESC like Tekin RS Pro in the touring car stock class if your claim is true. Extra output current definately give advantage, otherwise everyone would be running a 60A ezrun.
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Old 06-26-2010, 01:59 AM   #992
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[QUOTE=yobouno;7592211]it's actually simple science. you have something that have an output of 120A. it will need more current to provide the output. The power might not be transfered to the motor, but it will end up as heat. therefore drain your battery in the form of heat.

I might not be an expert in RC, but I know my physics.

Also to counter your arguement, why would one need an expensive ESC like Tekin RS Pro in the touring car stock class if your claim is true. Extra output current definately give advantage, otherwise everyone would be running a 60A ezrun.[/QUOTE

I'm an electrician and your full of it. The ammount of current drawn will be directly related to the power drawn by the motor not the esc output. Ohms law dictates this a=p/v where p is power drawn and no your motor doesn't put out the same power at quater throttle as it does at full. But you know
physics so you should know that already.
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Old 06-26-2010, 02:04 AM   #993
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Originally Posted by yobouno View Post
Wouldn't that depend on the ESC?. it will draw the amount of current it needs to run the ESC and motor. The rest is lost in the form of heat.

So overall lost = draining of power supply.
As I added above ....

Under your analogy a 21.5 turn motor will drain the battery just as quick as a 3.5 motor and the ESC will get just as hot and the battery will be drained just as quick using a 21.5?

The current draw is dependant on the motor used .... not the amp rating of the ESC. In fact generally the higher amp ESC's also have a lower internal resistance which generally equates to slightly better power transfer and I would assume lower heat.

All I was getting at is that the information you gave was very misleading to the end user
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Old 06-26-2010, 02:07 AM   #994
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So why would one need an expensive ESC like Tekin RS Pro in the touring car stock class if your claim is true. Extra output current definately give advantage, otherwise everyone would be running a 60A ezrun.

A lot of stock racers do not use the RS Pro. They use the RS which is lower rated. Again it is related to the motor used. And the new Extreme Stock ESC being released by Hobbywing is only a 60A as well

Racers only pick the higher rated ESC (RS Pro) if they think they might end up using a faster, higher drain motor
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Old 06-26-2010, 02:09 AM   #995
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I'm an electrician and your full of it. The ammount of current drawn will be directly related to the power drawn by the motor not the esc output. Ohms law dictates this a=p/v where p is power drawn and no your motor doesn't put out the same power at quater throttle as it does at full. But you know
physics so you should know that already.
first law of physics, energy input = energy output. So it has to go out in some other form. Still doesn't explain why ppl need super expensive high current ESC to run fast on standard 17.5T stock class. software programming is one thing, but surely the additional current plays a part, otherwise why do you need it?

Also this does not explain why your motor runs hotter on a more powerful ESC as well. Your argument using ohms law does not really applies. It is all about the ESC and how the ESC handles the current output and what it does to the motor. Let's make it simpler. Let just talk at full throttle.
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Old 06-26-2010, 02:14 AM   #996
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As I added above ....

Under your analogy a 21.5 turn motor will drain the battery just as quick as a 3.5 motor and the ESC will get just as hot and the battery will be drained just as quick using a 21.5?

The current draw is dependant on the motor used .... not the amp rating of the ESC. In fact generally the higher amp ESC's also have a lower internal resistance which generally equates to slightly better power transfer and I would assume lower heat.

All I was getting at is that the information you gave was very misleading to the end user
OK, your point is true in that sense. But your talking about the draw required. I want to know if given 2 same motor, 1 running 60A and the other one running 120A. at full throttle, wouldn't the ESC be pushing 120A to the motor? Which at that time will end up as heat because the motor doesn't need that much current to run it.

Also from the point you mentioned, does that mean, all 17.5T motor are not made equal?
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Old 06-26-2010, 02:28 AM   #997
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OK, your point is true in that sense. But your talking about the draw required. I want to know if given 2 same motor, 1 running 60A and the other one running 120A. at full throttle, wouldn't the ESC be pushing 120A to the motor? Which at that time will end up as heat because the motor doesn't need that much current to run it.

Also from the point you mentioned, does that mean, all 17.5T motor are not made equal?

Dont understand your 17.5 question. Most 17.5's are designed around a kV rating ... that is rpm per volt) so their performance is similar
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Old 06-26-2010, 02:33 AM   #998
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first law of physics, energy input = energy output. So it has to go out in some other form. Still doesn't explain why ppl need super expensive high current ESC to run fast on standard 17.5T stock class. software programming is one thing, but surely the additional current plays a part, otherwise why do you need it?

Also this does not explain why your motor runs hotter on a more powerful ESC as well. Your argument using ohms law does not really applies. It is all about the ESC and how the ESC handles the current output and what it does to the motor. Let's make it simpler. Let just talk at full throttle.
Doesn't the first law of physics refer to motion? Not electricity, Voltage is pressure, current is flow. and the energy is the wattage drawn by the motor NOT what the ESC puts out. Simple physics: More pressure more flow not the other way around. No matter how much you want it to. Your 20a power supply doesnt put out 20a all the time, just when it's being drawn.
Yes Ohms law applies, it always applies when dealing with electricity: Amps drawn= Power needed/Voltage available. End of story

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OK, your point is true in that sense. But your talking about the draw required. I want to know if given 2 same motor, 1 running 60A and the other one running 120A. at full throttle, wouldn't the ESC be pushing 120A to the motor? Which at that time will end up as heat because the motor doesn't need that much current to run it.

Also from the point you mentioned, does that mean, all 17.5T motor are not made equal?
At full throttle your 60a esc can put out more than 60a. Ground breaking isnt it. maybe its putting out 80a? It wont last forever doing that but it will do that. The 120a running the same motor wont be using all 120a it is rated at it will use the ammount needed, more or less the same as what the 60a will be putting out. So when you run a lower turn motor that draws more current you need a higher rated ESC.
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Old 06-26-2010, 02:36 AM   #999
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Dont understand your 17.5 question. Most 17.5's are designed around a kV rating ... that is rpm per volt) so their performance is similar
Firstly, thank you for enlighten me. It's very hard to learn in my club because everyone is trying to do 1 up from the other, so you either end up being the sheep copying what other does.

Having discussion is how I learn, I hope you guys understand.

As to my question. say a 17.5T motor, as you said they are designed around the same kV rating. Gearing aside, would a 60A ESC give equal performance to a 120A ESC?

From my observation at the club I go to, the ones with higher power esc EG ones with RS pro, do have to cool their motor more than those who runs a low power ESC. Assuming they are running the same gearing.

Hences my conclusion, if you're wasting all the extra energy on heat, the waste gotta come from somewhere.
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Old 06-26-2010, 02:41 AM   #1000
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Doesn't the first law of physics refer to motion?
that's newton's first law. For every action there is an equal reaction.

Anyway, I'm still confused as to why I've spent thousands of dollars just to try to keep up with the rest of the guys running a stock class motor.

I know it could be gearing. But everyone is running RS pro or LRP SPX or SXX, and running an xerun 60A just can't keep up with them on straight line.
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Old 06-26-2010, 02:45 AM   #1001
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Dont understand your 17.5 question. Most 17.5's are designed around a kV rating ... that is rpm per volt) so their performance is similar
No not all motors are designed and built the same. Differences in copper quality, the number of strands of wire and the diameter of these strands that are used to form the coils can cause massive differences in internal resistance thus affecting the ammount of current drawn. Ohms law again Amps= Volts/Resistance. Less resistance more current drawn.
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Old 06-26-2010, 02:48 AM   #1002
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Originally Posted by yobouno View Post
Firstly, thank you for enlighten me. It's very hard to learn in my club because everyone is trying to do 1 up from the other, so you either end up being the sheep copying what other does.

Having discussion is how I learn, I hope you guys understand.

As to my question. say a 17.5T motor, as you said they are designed around the same kV rating. Gearing aside, would a 60A ESC give equal performance to a 120A ESC?

From my observation at the club I go to, the ones with higher power esc EG ones with RS pro, do have to cool their motor more than those who runs a low power ESC. Assuming they are running the same gearing.

Hences my conclusion, if you're wasting all the extra energy on heat, the waste gotta come from somewhere.
THe faster guys with 17.5 will most likely have different ESC profiles. The fact that they are running hotter as you say would generally mean that they are running more timing (assuming equal gearing and same ESC)

In recent time Hobbywinmg has released a firmware that means the HW ESC has dynamic timing like the Tekin and LRP. Owners of HW 60A ESC's will now be able to keep up. In fact in Sydney recently on the large Moorebank a racer using a 60A HW ESC won the 10.5 class so he was hardly at a disadvantage
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Old 06-26-2010, 02:53 AM   #1003
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THe faster guys with 17.5 will most likely have different ESC profiles. The fact that they are running hotter as you say would generally mean that they are running more timing (assuming equal gearing and same ESC)

In recent time Hobbywinmg has released a firmware that means the HW ESC has dynamic timing like the Tekin and LRP. Owners of HW 60A ESC's will now be able to keep up. In fact in Sydney recently on the large Moorebank a racer using a 60A HW ESC won the 10.5 class so he was hardly at a disadvantage
Man, am kicking myself ATM for buying the new LRP SXX... should have just upgrade the firmware instead. BTW, when you refer to HW 60A esc, it's the sensored one right? the Xerun not the Ezrun ESC.
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Old 06-26-2010, 03:02 AM   #1004
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Man, am kicking myself ATM for buying the new LRP SXX... should have just upgrade the firmware instead. BTW, when you refer to HW 60A esc, it's the sensored one right? the Xerun not the Ezrun ESC.

Yes the Xerun 60A sensored. You simply need the LCD Program box and you can upgrade the software to make the ESC competitive with the other brands
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Old 06-26-2010, 03:34 AM   #1005
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Firstly, thank you for enlighten me. It's very hard to learn in my club because everyone is trying to do 1 up from the other, so you either end up being the sheep copying what other does.
Maybe some members at your club should lighten up. Knowledge is to be shared so together we know more.
At the end of the day were racing TOYS for little cups.
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