Title: resistor question Post by: Darth Money on August 08, 2015, 05:14:00 PM Does anyone know what size resistor is needed for a normal build with the red LED. I am new and this will be my first saber build I am also putting in a buck puck
Title: Re: resistor question Post by: Racona Nova on August 08, 2015, 07:41:51 PM I don't know exactly, but I think I've read something that the red diode doesn't need to be resistored when you use a BuckPuck.
Maybe someone could confirm/correct that? What I definitely know is that you have to do that when you're building a resistor-only setup. Title: Re: resistor question Post by: Darth Money on August 08, 2015, 10:30:58 PM hope so I just don't want to screw up my first build and eventually I will add sound to it at a later date
Title: Re: resistor question Post by: TEmmett on August 08, 2015, 11:31:25 PM I've been looking up the same thing myself, trying to switch a couple of mine over to the li-po setup.
Here is what I have in mine without sound: Blue Cree LED -> 2ohm 3w 5% resistor -> 4AAA battery holder. Resistor is on the ground wire, while the hot wire runs through the switch. White LED -> Buckpuck -> Li-Po battery holder. I cannot find a resistor wired in this setup. It would appear that the Buckpuck does not need a resistor; from what I've found its job is to regulate the output amperage anyway. The data I can find on the Luxdrive LEDs that both of my sabers have suggest that a Red LED would need 2.3v @ 700ma. The sabers I have with sound also have the Emerald driver, which does the voltage regulation in this case. I wouldn't think that would need to be different, but I can't say for sure. Title: Re: resistor question Post by: Darth Money on August 09, 2015, 12:31:44 AM that's a big help appreciate it I seen people complain that they burned out their LED but the pics didn't show a resistor or anything on it so I wanted to make sure that I learn from others mistake lol hard enough taking the wife into letting me spend what I have
Title: Re: resistor question Post by: Darth Money on August 09, 2015, 01:06:21 AM what gauge wire is best to use when wiring them up?
Title: Re: resistor question Post by: TEmmett on August 10, 2015, 12:16:56 AM The battery holders use 26Ga wire. My sabers have heavier wire between the resistor/switch and LED, but I wouldn't think it would need to be heavier than the power supply wiring. Also, there is a 700ma Buckpuck that would probably suit the Red LED better (the Blue, Green and White can take 1000ma). I hadn't looked at the one US sells separately, so I dunno if it's the 700 or 1000ma model.
Title: Re: resistor question Post by: Kouri on August 10, 2015, 01:41:19 AM My understanding is US is using Cree LEDs on their sabers, even if they're mounted to a LuxDrive star. Those'll run 2.59v @ 1000mA.
But yeah, if you're using a buckpuck, circuit'll go something like this: Battery positive > Latching switch > Buckpuck > LED > Battery Negative You won't need a resistor with the buckpuck, but you should have 7v to run the puck. 4x AAA alkalines will only put out 6v, so you'll need two Trustfires wired in series or a custom Lithium pack that runs at 7.4v. Title: Re: resistor question Post by: TEmmett on August 10, 2015, 02:05:48 AM The numbers I listed came from a data sheet for the Cree XP-E http://www.cree.com/~/media/Files/Cree/LED%20Components%20and%20Modules/XLamp/Data%20and%20Binning/XLampXPe.pdf (http://www.cree.com/~/media/Files/Cree/LED%20Components%20and%20Modules/XLamp/Data%20and%20Binning/XLampXPe.pdf)
No listing for red @ 1000ma on it, so I assumed 700ma was the preferred amperage. If it's an XP-E2, the numbers you listed match their data sheet http://www.cree.com/~/media/Files/Cree/LED%20Components%20and%20Modules/XLamp/Data%20and%20Binning/XLampXPE2.pdf (http://www.cree.com/~/media/Files/Cree/LED%20Components%20and%20Modules/XLamp/Data%20and%20Binning/XLampXPE2.pdf) Given that US only sells the 1000ma Buckpuck, I would imagine that it's this one; I've not seen anything on any of my LEDs that would confirm which version it is. Title: Re: resistor question Post by: Sarich Belmont on August 10, 2015, 03:48:04 PM You only need 5v to run a buckpuck, but I would actually recommend using a resistor and a single 18650 cell instead of AAA batteries. You'll get a much brighter saber that way.
Title: Re: resistor question Post by: Kouri on August 10, 2015, 04:01:38 PM Huh, appears I mis-remembered the data sheet. You're right, 5v is the minimum input on a puck. Still, the max output voltage is 2.5v less than the input, and there are only so many LEDs that'll run on 2.5v, regardless of the mA. I'd say a safer minimum would be 6v, since a max of 3.5v should cover most single diodes.
I'll also vouch on the 18650 + resistor combo. Managed to wire up a Rebel Lime LED with a 1ohm 2w resistor, and that thing shines bright enough to light up a room. Title: Re: resistor question Post by: Darth Money on August 10, 2015, 06:40:30 PM cool thanks for all the info I will post when I get it all together I am just waiting on my parts to arrive
Title: Re: resistor question Post by: Sarich Belmont on August 10, 2015, 08:53:35 PM Yeah, Buck Pucks aren't really as useful as they once were. I would still use them in a build that used 4 alkaline batteries, but anything else it's better to just use a single 18650+resistor. You don't get any more brightness from the extra voltage and the Puck actually limits the current being supplied if you are using, say, a Tri-LED, so it isn't useful at all there.
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