LED Setup?

[Taki117]

So, I'm planning my first saber build, and being a tad OCD I like to know what I'm doing.

For My setup I'm running the following(With other additions, but this is the main bit I'm having issues with)

PC v3.5 and RB/RB/W Tri-Cree LED and a 7.4v Li-ion 1050mAh 14650 Battery Pack

My biggest questions come from how to wire up the RB/RB main blade color. Since I'm not using color Mixing would it be better to wire them in series or parallel? I'm thinking series, but I'm not sure if I need a resistor, or if I should put just a 1 Ohm one on there to be safe.

Now, for my FoC i'm calculating R=(7.4-3.3)/1 = 4.1 Ohm 4W resistor, is this correct, or is there something I'm missing?

[Forgetful Jedi Knight]

If you are wiring them to the main channel of the PC, you don't need a resistor at all and you can wire them in series. I STRONGLY recommend you read through the PC manual. You would need a resistor for the W FoC die though.

[sgcdialler]

I thought I'd seen almost this exact question before a couple months ago. Found the thread I was thinking of here.

You'll want to wire the rB+rB in series, coming off of the main LED driver pads on the PC. The board controls the current there so you won't need a resistor for those.
The wiring setup for the FoC LED is described in the PC3.5 manual starting on page 27, if you need that. Looks like your math for the resistor is right, though I'm not familiar with standard resistor values enough to know if you can find them with those exact values.

[Taki117]

Looks like your math for the resistor is right, though I'm not familiar with standard resistor values enough to know if you can find them with those exact values.

Thanks, I'm sure I can find something close, and if not I can always just order one from TCSS so it's not a big deal.

[Bark]

For the White FoC, I get these numbers:

White Cree Part# XPEBWT-L1-0000-00F51
266 Minimum Luminous Flux @ 1000mA
Forward Voltage @1000mA = 3.15v

(7.4-3.15)/1 = 4.25 ohms
4.25*1^2 = 4.25 watts

Rounding up, I would use this guy, a 4.7ohm 5w resistor.

Also in case you missed it, bookmark this page.

[Taki117]

For the White FoC, I get these numbers:

White Cree Part# XPEBWT-L1-0000-00F51
266 Minimum Luminous Flux @ 1000mA
Forward Voltage @1000mA = 3.15v

(7.4-3.15)/1 = 4.25 ohms
4.25*1^2 = 4.25 watts

Rounding up, I would use this guy, a 4.7ohm 5w resistor.

Also in case you missed it, bookmark this page.

Thank you for those, would a 10W resistor be just as good/better than the 5W? I will have to see what's available at work (I work in IT at a technical college so we have lots of spare resistors and wire)

[Silver Serpent]

A 10W can be used in place of a 5W, but it will take up more room in the hilt. I avoid the 10W resistors whenever possible, because they're HUGE.

[Bark]

Yes, more wattage for the resistor is erring on the safer side and works, but like Silver Serpent said, it becomes a space issue. Even at 5W, you have 0.75W more than you need. You'll be fine.

[Taki117]

Yes, more wattage for the resistor is erring on the safer side and works, but like Silver Serpent said, it becomes a space issue. Even at 5W, you have 0.75W more than you need. You'll be fine.

Alright then, thank you both.