Wiring Multicolor LED, FoC, mA CF question?

[Padawan23]

Hi all!

I would like some second opinions on wiring my Ledengin 10w RGBW on a CF 4.3 please, here is how it will be wired...

The R and B wired in series (no resistor) for main led set to 1.5A (so each will get 750ma?)

The W wired for COF via power extender with 3watt 4ohm resistor on cathode wire (because im running 7.4v from 2 14650's and the white die has a Vf of 3.7v and a maximum ma of 1000)

power extender will get its (+) & (-) from the boards (+) & (-) where the battery connects to the CF, and the PE's clash wire will be connected to the CF's static clash pad.

if someone could verify that this is correct i would be very greatful, many thanks

oh lastly, if the red die has a Vf of 2.6v and the Blue die has a Vf of 3.7v and i wire them in series, how will the CF know how much Voltage to give each die? or will it just be 2.6+3.7=6.3 / 2 = 3.15 volts to each die? would the red die not pop?

[Arkhan]

wiring the R and B in series will present a 6.3v  Vf to the board.

I believe your current calculation is also incorrect.  In both cases, you are confusing series and parallel wiring effects on the resistance and current.

Someone who has much more experience with CF boards will step in shortly and help you out

[LUMINARA UNDULI]

No.  If you wire the R & B in series for the main LED you will get 1.5A to both dice (you only divide in a parallel set up).  You never use a resistor for the main LED with a CF because it sense voltage ;).  My suggestion would be to use around 1.2A that would be safer and seems to be the "sweet spot" for purple. 

The PE positive goes direct from the battery and the negative from the recharge port (less wires) and the aux pad on the PE is connected to the clash pad on the CF. 

As far as the last question, the CF measures voltage across both LEDs combined.  It is like they are becoming one LED.  It will not pop ;).

[Padawan23]

Ah i see, got it, so the main die in series at 1.2a (slightly overdriven). Thanks!

Am i still correct in the white die for COF having a 3watt (due to heat dissipation) 4 ohm (to bring the ma to a safe 700 ish mark) resistor?

I understand that different ohm resistors will yield different mixes of color flash but i'd like to know if im in the safe zone using this resistor? (hopefully i'll get a light purple/pink bright flash but thats for me to experiment with and part of the fun as long as im not resisting it dangerously and tempting a blow out without knowing.

Much appreciated everyone! Especially luminara for the ma purple tip ;)

[Novastar]

For FoC, if you have an LED fwd v of ~3.7... and your battery solution is ~7.4v... yup, 4ohm + 3w capable is not a bad idea.

I have done 3.3ohm + 3w capable before, and it is also fine, due to the fact that it is only on briefly.  Again, this is ONLY talking about ~7.4v battery with a ~3.6v FoC LED.

Biggest problem with people doing these kinds of setups is... they think "one way" is the cure-all.  It never is.  As Erv likes to say (OFTEN!)... c'est depuis, c'est depuis, c'est depuis... it depends, it depends, it depends.  :)

There is also nothing wrong with testing some possibilities, especially if you've already determined that you won't be WAAAAAAY overloading an LED (or any other device for that matter).  In other words... if you give an LED 4v instead of "3.6"... it will not harm it.  It's only when you give it... saaaayy... 9v instead of 3.6 that you can have issues!!!  You have to be WAAAAAY off with calculations in order to do some damage... and even if you DO... well, there's your $8 to $30 lesson.

Ultimately, LED / voltage calculators are GREAT tools.  They aren't "perfect" for dialing in the very most perfect setup for *YOU* and YOUR needs of a SPECIFIC project... but they will get you "in the ballpark".

[Padawan23]

Thank you, its very reassuring to know that a similar setup has benn done before  :D
I will remember that although a certain resistor for a certain voltage on a certain LED will work, it may not be the case if one or more factors are changed on a different setup.

It's good to learn a lesson before making a mistake  ;) , thank you very much Arkhan, Luminara and Novastar for all the help, i have benefitted a lot from your posts and hopefully many more padawans will have gained something by reading this too.

[Novastar]

No problem.

Something you might consider (which I actually use for my Flange III Lightside saber) is also using the additional pad for FoC.  In other words, for example:

RB = purple (~7.2v @1A, although it could also be wired for ~3.7v @2A if you are using CFv5.x)
GW = FoC (~7.4v)

This isn't to say that you have to use these color mixtures, but it's only to show that you can essentially avoid bothering with a huge resistor (or even one at all) if you use two dies for the FoC... based on the fact that the voltage is doubled from your previous setup of only a single die (~3.7v), and so, since the voltage now matches a Li-Ion ~7.2v solution so closely... you don't really need to resist much, if at all.

Additionally, as you'll see in the video above, you COULD allow yourself the option to "swap connectors" so that you could easily alter the color of the saber (and FoC).  Kind of hard to explain in words, but--the video tells the story.

The only way this works, however... is if the voltage requirements are (essentially) matched up.  In my case, we have:

RGBA
GB = "Line 1"... or the Main Blade, I guess, in the beginning at least
RA = "Line 2"... or the FoC, I guess, in the beginning at least

So, they can be swapped (not HOT-swapped... but... swapped).

This is NOT a CFv5.x, so it cannot output 2A... so... for anyone thinking "why didn't you wire it for ~3.7v @2A"... that's why.  :)

I'll have to try an RGBW sometime... but for now... I really want to see "RRRW" or something, heheh!

[Padawan23]

thanks for that Novastar, i took your advice and used G+W for FOC and its much brighter! love your videos by the way lol cheers

[m4rco]

Hey as the topic indicates:

I want to wire a RGBW LED on to a CF. I would like to use a pex to produce a FoC.
The CF manual says one should be careful with the mA one provides for the LED dies...

1. If I configure the CF for lets say 1200 mA for the RB main LEDs to get a purple blade.
By wiring red and blue in series will these 1200 mA be divided to 600 mA or will both leds get 1200 mA? (Difference if the are wired in series? Voltagedrop or anything?)

2. Moreover if I output 1200 mA and the max discharge rate of the batt is 2000 mA do I have to use a resistor for the FoC die that limits the mA to 800?
Because more could, as the manual says:
"Exceeding the capacity of the battery pack, or its discharge rate could lead to battery deterioration or explosion."?

Thanks in advance,

Marco

[m4rco]

 ;D

[ANAKIN SKYWALKER]

It depends... What color FoC are you trying to produce?  do you want the white and green for a greenish-white?  or just the white? 

Also, you can't define the FoC current on the CF config, you must use a resistor for that (you didn't mention it, so I wasn't sure if you knew)

And what batteries are you using specifically?

[m4rco]

2. Moreover if I output 1200 mA and the max discharge rate of the batt is 2000 mA do I have to use a resistor for the FoC die that limits the mA to 800?

Just a white clash.

Source voltage 7.4 v

[ANAKIN SKYWALKER]

no, I mean like trustfire 14500s, aw 18650s, tenergy 14500s.... specifics.   ;)

[m4rco]

18500 1400mah These --> http://www.ebay.de/itm/250501191337 to be specific (# Max. Discharging current 2.5C ( 3.5A ) )

But what about my q concerning the mA? 1200 mA setting dies in parallel each die gets 1200 mA or just 600 mA? Or will even 2400 mA been drawn? (Difference if they are wired in series?)

[ANAKIN SKYWALKER]

when you wire in parallel, you are giving 1200ma to both dice.  Hard to explain how it is distributed, and you should be using a resistor in // for purple on the red, but assuming you already know that, your pack will be fine with whatever current you give to the FoC (assuming your goal isn't to blow the led and since the power xtender is limited to 2A anyway).