Tri Crees and Crystal Focees

[Forgetful Jedi Knight]

I don't know where you're getting the fact that the main pad only puts out 3.3V. It looks to me like you're not really reading through the manual, you're trying to skim through it and guess.

Also Power Extenders, and Color Extenders are two different things.

[FenixFire]

I don't know where you're getting the fact that the main pad only puts out 3.3V. It looks to me like you're not really reading through the manual, you're trying to skim through it and guess.

Also Power Extenders, and Color Extenders are two different things.

Sorry FJK, I just took that (3.3v) from his drawing, I did not go back to the manual to double check that one.

[Manadono]

Okay, I don't understand. The main Luxeon drive channel can drive up to 3A in 3 minute bursts, 2A stable, but is then documented to be set to a 1A limit in the prefs file. Beyond this, no mention of its use beyond 1A is made (although Erv mentions setting the max amperage over channels 2-4 to 1.5A for pseudo colour mixing). As the channel seems to be able to operate safely at 2A, surely it would be A-ok to drive both red dice in parallel, as long as the loads were balanced?

Please understand that circumventing common operation to achieve a non-standard stable and viable operation requires some in depth understanding of how the board handles power. I am asking your opinion on electronics, I have the manual, and until I solve this problem (or memorise it cover to cover) of course I will be using it as my main source material. However I am not an electrician, and I know when I need an extra brain on the job, this is why I ask for help, not because I can't read, or can't be bothered to put the leg work in myself.

[Forgetful Jedi Knight]

You could run the 2 of them in parallel though I don't know why you would need to, depening on your battery setup.

[Manadono]

You could run the 2 of them in parallel though I don't know why you would need to

I have a 7.4V cell, as my understanding stands, the PeX channels are at battery level voltages and running a single red die on 7.4V needs "a chock off power resistor" to keep the LED from exploding. Running the small load of two red dice on the main channel will let the blade be dimmed in and out, and edited in RICE if need be, on a current controlled channel without excessive voltages, and the green die can run on the PeX channel for FoC because it's only going to be on momentarily.

Anyway, considering what I know I have been away with a sandwich and some paper and I have drawn up some values.

Assuming that channel 1 is current controlled, and all things being perfect, is outputting 1.4A to the Red (Vf 2.19V) and Photo Red (Vf 2.225V) in parallel, with a 0.05Ω (0.00175W, I'm assuming this means any small resistor will do) resistor on the Red line to balance the forward voltage difference, both LEDs will have their 700mA. I have no clue how the main channel deals with amperage and voltage though so any light on that subject would be great.

Then, assuming the PeX channel has a voltage of 7.4V, wired to the Green (Vf 2.95V) die with a 4.45Ω 5W resistor for FoC, all should be fine and dandy? I suppose the resistor could be a lower wattage on the FoC channel, but for safety's sake my reasoning is sound?

[Forgetful Jedi Knight]

If you have a 7.4V power source, ideally you would be smarter to run the Reds in series at 700mA. The dimming effects you descriped are (again) covered in the manual. You would need to adjust the Amperage to what you need, and the voltage will handle itself in the main LEDs. You wouldn't need a resistor for that assuming you are using the main LED pads.

The resistor for the Green sounds about right.

[Manadono]

I wasn't sure about running the two reds in series with there being different Vf over them both, but that sounds a lot simpler. I've just been trying to find info on the power flow through an LED because I remember that lab test from my physics class where power would decrease in series over incandescent bulbs, but then an incandescent bulb is purely resistive and I get the feeling diodes don't behave in the same way. Then again the difference in Vf is pretty small, maybe a teeny scooch of overdrive wouldn't kill it. Thanks for the tip!

[FenixFire]

If you can verify they are both XP-E then I linked to a screen capture of the the datasheet that shows that at 700mA the Red and PhotoRed are both 2.3v. I can PM you the full 44 page engineering doc if you would like. I do not have an XP-E2 in PhotoRed in that series data sheet.

http://i.imgur.com/yUOBzg5.jpg XPE
http://i.imgur.com/S89osq1.png XPE2

[Manadono]

the Red is an XP-E2, the Photo Red is XP-E... Oh flip, the If of the red is 1A.

just wired up a test @ 700mA series, everything went fine and the Red was super bright even though it wasn't at its full drive. although the Photo Red wasn't as exciting as I expected it to be, looks like it should be fine running them in series on channel 1 :>, came to about 4.3V.