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Old Mar 01, 2011, 06:21 AM
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Ouderkerk a/d ijssel (Holland)
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LED's on a Brushless ESC

Hi all,

Is it posible to conect leds between the 3 wires of a brushless ESC.
Will it affect the ESC or not...

Is there someone who can tell me more...?
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Old Mar 01, 2011, 07:55 AM
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Bonnie Scotland
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Quote:
Originally Posted by theflyingeagle View Post
Hi all,

Is it posible to conect leds between the 3 wires of a brushless ESC.
Will it affect the ESC or not...

Is there someone who can tell me more...?
Yes it is possible to connect them but it is unlikely anything would happen.

What you need is a brushed esc with only 2 wires. There are pleny of threads here which cover that.
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Old Mar 01, 2011, 08:29 AM
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Originally Posted by electrotor View Post
Yes it is possible to connect them but it is unlikely anything would happen.
.
Have you done this before..?
I think it will work but Iím not sure of the ESC is capable of handling some extra LED's...
A brushless ESC does some measurements I believe...
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Old Mar 01, 2011, 11:38 AM
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Originally Posted by theflyingeagle View Post
Have you done this before..?
I think it will work but Iím not sure of the ESC is capable of handling some extra LED's...
A brushless ESC does some measurements I believe...
A brushless esc works by converting the battery DC into phased AC. LEDs use DC.

IS THIS A WIND-UP?
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Old Mar 01, 2011, 12:14 PM
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Quote:
Originally Posted by electrotor View Post
A brushless esc works by converting the battery DC into phased AC. LEDs use DC.

IS THIS A WIND-UP?
Got it... but still..

I have done it... it works... a LED is a diode so when de ESC is going negative it will block, no problem.
But i didn't like it, my motor starts to squeal a bit and it stops like the brake is on..

So i removed the LED's and leave it by this experiment, just use a Brushed for LED control...
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Old Mar 02, 2011, 02:18 AM
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Graz - Austria
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Quote:
Originally Posted by electrotor View Post
A brushless esc works by converting the battery DC into phased AC. LEDs use DC.
IS THIS A WIND-UP?
As said a diode will work in one way and block in the other. So that's not the problem. Max. blocking voltage might be lower than the battery voltage - could burn the LED.

More of a problem will be the software. As you see with some motors, if something goes wrong the motor just stutters and won't run. As the diodes won't return the signals as a motor does it certainly won't "run". So I dont't think you will see more than a short flash.

RK
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Old Mar 02, 2011, 04:44 PM
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Your ESC is potentially dumping many amps into the motor. A typical LED wants 0.02 amps.

It should be easy to see why this is a bad idea.
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Old Mar 03, 2011, 04:43 AM
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Originally Posted by 691175002 View Post
Your ESC is potentially dumping many amps into the motor. A typical LED wants 0.02 amps.

It should be easy to see why this is a bad idea.
A LED should always be used with a resistor or other kind of current limiting device which can not be an ESC (BL or brushed).

The ESC dumps no AMPs !!!!!!!! It just sets a voltage and the motor draws as much current as voltage, rpm and prop need. A 100A ESC can also drive a 1g motor. It just will be heavier than the plane :-)

RK
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Old Mar 03, 2011, 03:14 PM
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Originally Posted by rkopka View Post
A LED should always be used with a resistor or other kind of current limiting device which can not be an ESC (BL or brushed).

The ESC dumps no AMPs !!!!!!!! It just sets a voltage and the motor draws as much current as voltage, rpm and prop need. A 100A ESC can also drive a 1g motor. It just will be heavier than the plane :-)

RK
By dump I didn't mean force the maximum current through at all times. Either way your point is at best a technicality since setting voltage and providing current are just two sides of the same coin.

My point is simply that almost any brushless/esc combo will be dealing with far more current than an LED could ever survive which makes this a bad idea even without considering how a diode would screw with the ESCs feedback monitoring.
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Old Mar 04, 2011, 01:05 AM
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Originally Posted by 691175002 View Post
By dump I didn't mean force the maximum current through at all times. Either way your point is at best a technicality since setting voltage and providing current are just two sides of the same coin.
Yes and no. For electricity we differentiate between current and voltage sources. A voltage source provides voltage and allows current to flow.
A current source will provide (in theory) any voltage it needs to let a set current to flow.
An ESC is a voltage source. It normally doesn't care for current. The better ones shut down if a max. current has been reached. The cheap ones just go up in smoke :-)

Quote:
My point is simply that almost any brushless/esc combo will be dealing with far more current than an LED could ever survive which makes this a bad idea even without considering how a diode would screw with the ESCs feedback monitoring.
A diode has a voltage by that it begins to conduct. If there is no resistance added the current will rise very fast above this voltage. So it's no good idea to use a LED without a resistor even if the voltage is very near to the LED flow voltage or it will easily burn.
So any LED installation without a dedicated current source/limiter needs a resistor in series.

The current value of an ESC doesn't matter because that's just the value the ESC will get to its limit. It will usually provide more current with the strong risk of destruction.
I just write this because from other posts I found that some people don't get the current value correct. They think if they take a 20A ESC the current will not go higher no matter what motor they use !

So apart from the question if a BL ESC will work at all, a LED needs a resistor(or such) in any case. And the current value of the ESC doesn't matter.

Even if you could setup the ESC to switch on in such short pulses that the average current will be in the LEDs range, it will burn the LED because the current spikes are too high.

RK
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Old Oct 11, 2013, 04:28 PM
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Here is one that works but not sure how he wired it:

ESC v0.3 driving the LED harness after repair (0 min 22 sec)
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Old Oct 13, 2013, 04:13 PM
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Nice find Dave!

His circuit emulates the "K" motor winding. The LEDs, which are diodes, are wired in diametric opposition. That means one if forward bias and the other is reverse bias as the ESC switches phase. That's why you see them alternatively flash as the throttle is advanced. The resisitor on each leg acts as a current limiter. At higher switching speeds you can't see the flicker. A bit of overkill to make a LED light....but....NEAT!
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Old Oct 13, 2013, 04:51 PM
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I thought the idea of using a brushless ESC had some potential so I mocked up a couple different circuits using LEd strip. I attached one ESC lead to the each end of the positive bus and the remaining lead to the negative. The LED strip would blink at low throttle but then go off past mid throttle. I suspect this is due to not sensing any change in the motor position during the idle phase of the cycle. The brushless ESC depends on sensing the motor position thru the idle phase wire. My guess is it errors out at some point of not sensing the motor turning.

I then tried 2 pieces of LED strip diametrically opposed. I swapped the positive and negative at the central junction and wired one lead to the negative bus, and one to each end of the pseudo positive bus. Same results. Flashing at low throttle and goes off past mid throttle.

Neat idea. Different ESCs, different timing settings may give different results. Cool experiment.
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Last edited by Barn-E-Stormer; Oct 13, 2013 at 04:56 PM.
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