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Topic: High power leds and led strips (Read 5405 times) previous topic - next topic

septillion

Adding more solder to remove something is the easiest way most of the time ;) Especially if you have solder with lead and they used (horrible) lead-free. And the extra solder help transferring the heat to the component quicker so it's easier to remove it quick. So good job! :) And luckily you don't need to reuse the resistor or the pads and the board can handle a bit of abuse ;)
Use fricking code tags!!!!
I want x => I would like x, I need help => I would like help, Need fast => Go and pay someone to do the job...

NEW Library to make fading leds a piece of cake
https://github.com/septillion-git/FadeLed

outro

#31
Mar 16, 2017, 09:52 pm Last Edit: Mar 16, 2017, 10:02 pm by outro
Hmm, more volts = less amperage?
6.3V = 380mA
10.0V = 230mA
12.0V = 190mA

Did I miss something

( But it works ! :D Finally ! )

septillion

I have no idea how you connected what and what you measure...

Sorry, crystal ball still out for repair... ;)
Use fricking code tags!!!!
I want x => I would like x, I need help => I would like help, Need fast => Go and pay someone to do the job...

NEW Library to make fading leds a piece of cake
https://github.com/septillion-git/FadeLed

outro

I have no idea how you connected what and what you measure...

Sorry, crystal ball still out for repair... ;)
Bottom wires of picture: Vin and Ground
Mini breadboard: High power led ground/vin

septillion

Ahhhhh, input voltage and input current, then yes! The converter is efficient!

And the laws of power state that P = U x I. So if you want the same power to the led you need less current for a higher voltage. That's why a socket has 230V on it, not just 1.

6,3V x 380mA = 2,4W
10,0V = 230mA = 2,3W
12,0V = 190mA = 2,3W

All pretty much the same. Not 100% but that's because the converter is pretty efficient but it's not 100% efficient and the efficiency depends a bit on the voltage. But it looks like the converter is more efficient on higher voltages.
Use fricking code tags!!!!
I want x => I would like x, I need help => I would like help, Need fast => Go and pay someone to do the job...

NEW Library to make fading leds a piece of cake
https://github.com/septillion-git/FadeLed

outro

Ahhhhh, input voltage and input current, then yes! The converter is efficient!

And the laws of power state that P = U x I. So if you want the same power to the led you need less current for a higher voltage. That's why a socket has 230V on it, not just 1.

6,3V x 380mA = 2,4W
10,0V = 230mA = 2,3W
12,0V = 190mA = 2,3W

All pretty much the same. Not 100% but that's because the converter is pretty efficient but it's not 100% efficient and the efficiency depends a bit on the voltage. But it looks like the converter is more efficient on higher voltages.
Ah, so the brightness will stay the same even if the current (draw?) is smaller?
Weird

Also, I think it heats less with more voltage?

septillion

It's not weird. :D The current to the led is constant. But so is the voltage over the led. Which results in a constant power. And the power is what determines the brightness ;)

Looks like the regulator is more efficient at higher voltages so less heat there. For the led it's all constant so that still needs a beefy heat sink for that 2,3W.
Use fricking code tags!!!!
I want x => I would like x, I need help => I would like help, Need fast => Go and pay someone to do the job...

NEW Library to make fading leds a piece of cake
https://github.com/septillion-git/FadeLed

outro

It's not weird. :D The current to the led is constant. But so is the voltage over the led. Which results in a constant power. And the power is what determines the brightness ;)

Looks like the regulator is more efficient at higher voltages so less heat there. For the led it's all constant so that still needs a beefy heat sink for that 2,3W.
This is wonderful, I just got the 'fade' example to work.
This is really amazing, I have been learning and planning and building and ordering stuff for like 4 months (of course doing other things in between :D), but it's coming all together now!

Although, how beefy are we talking about?
They will be mounted inside of this glass balls (somehow) for the desk lamp (2 different balls)

septillion

Don't know exactly how big. But 2,5W of heat is not insignificant.

Most of the time I just try stuff and test if the temperature is alright. A led is terrible at heat so things must stay touchable.
Use fricking code tags!!!!
I want x => I would like x, I need help => I would like help, Need fast => Go and pay someone to do the job...

NEW Library to make fading leds a piece of cake
https://github.com/septillion-git/FadeLed

outro

Got stuck with the project (wires :D) and starting again!

Thinner cables mean, 2 wires less.

So a question arises: can I use common ground? Instead of using 6 wires per led, I could use 4?

outro

Got stuck with the project (wires :D) and starting again!

Thinner cables mean, 2 wires less.

So a question arises: can I use common ground? Instead of using 6 wires per led, I could use 4?
So, a little clearer question:

When having a constant current sources ( X1,2,3 ) and a high power RGB LED ( Y ), can I have a common ground?
X1,2,3 --> Y --> GROUND?
Or do each
X1, X2, X3 need their own ground?

outro

Bumping this once more, before clearing out to a new topic (?)

Wawa

When having a constant current sources ( X1,2,3 ) and a high power RGB LED ( Y ), can I have a common ground?
X1,2,3 --> Y --> GROUND?
Or do each
X1, X2, X3 need their own ground?
Sorry, can't be bothered to read all the posts.
Simple answer is that you need six seperate wires to an RGB COB LED that's been driven by CC drivers (post#33).
Nothing can be common.
That usually means that you have to separate the common bar that is used on many COB LEDs.
Leo..

Boardburner2

Cannot be bothered either, but led strips can draw a lot of current. that current has to come out of the ground return so if you want to use fewer wires for ground they had better be thick.

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