Help with Econo Board wiring check

[Gnar-Gnar Gin]

Ok, so I'm using this diagram:
2010ModifiedNoVoltRegrev01-10-2011.jpg

with Royal blue rebel star: 3V(forward) 1000mA forward current
battery: 3.7v tcss pcp Li-ion
LED resistor: 1ohm 2watt http://led.linear1.org/1led.wiz?VS=3.7;VF=3.0;ID=1000

2 questions:

did I calculate the right resistor?

Is there any advatange/disadvantage between the 3.7v and 7.4 battery setups for econo boards?

[Silver Serpent]

Resistor is fine.

A 7.4v setup will allow you to run multiple LED dice in series, but you will need to add in a 5v regulator to keep from blowing your board.

The 3.7v setup will run single dice just fine, or multiple dice in parallel.

For multi-die LEDs, you'll get a longer runtime by running them in series with a 7.4 pack vs. running them parallel with a 3.7v pack. For single die LEDs, there's no point in using a 7.4v pack.

[Gnar-Gnar Gin]

so 3.7 is cool if Im running a rebel and 4 accent LEDs (20 mA each)?

[Silver Serpent]

Should be plenty.

[Gnar-Gnar Gin]

Thanks SS, You're the best!

Just placed another good sized order in to TCSS. I've been building PVC sabers for so many local kids it's crazy, and now being able to add sound is going to make them even happier!

A huge thanks to you and ForgetfulJedi and Tim. I just placed my first MHS order and am going to slowly start working on my first MHS build! Never thought I be making sabers, let alone work on a metal saber when I first found this site 4 years ago!

I wouldn't be were I am without all your help!

Thank You!

[Gnar-Gnar Gin]

So even though I'm using a TIP42G 5V pnp transistor, the source voltage to the LED is the 3.7 from the battery? or should it be 5v?

[Silver Serpent]

There's a 5v regulator, which you'll need if your battery pack exceeds 5v. There's also a TIP42 pnp transistor, which switches power over to your LED. The two components look similar, but they're not the same thing.

1. If you have a 3.7v battery pack, you'll calculate source voltage as 3.7v. You will not need a 5v regulator for this setup.
2. If you have a 7.4v battery pack and you're running the LED AFTER the 5v regulator, then the source voltage is 5v.
3. If you have a 7.4v battery pack and you're running the LED BEFORE the 5v regulator, then the source voltage is 7.4v.

[Gnar-Gnar Gin]

thanks for clearing that up SS, i misunderstood the pnp transistor.