LED : wiring Parallel vs Serial

[qaos]

Hi,

New to the forums and to building Lightsabers.
Been doing my research and reading (sorry I haven't read every post, so if I missed the answer, sorry.) watching videos, etc.

My question is about wiring up the LED's (Tri Cree) in either Parallel or Serial. (the two LED for color not FoC).

Is there a preferred way to wire up the LED's? (Parallel or Serial)

What are the Pros and Cons of each?

I assume there will be resistor differences? (Where to put them, which ones to use) (I think I saw that in one video).

Is there a preference as to where the resistors should go?
(For Parallel, should each + lead get its own resistor? or should you have on on the main + battery lead before it splits?

I am sure I will have other questions later as I get more comfortable with understanding all that is needed to build my saber and wire things up.
but for now, this should be a good start.

Thanks
Darth Qaos
(pronounced "chaos")

[Silver Serpent]

Well...it's complicated. I'll try to explain the differences.

Assuming you're wiring up two dice of your Tri-Cree:

Wiring in series, you will add up the forward voltages of two dice, but the current will remain the same as a single die. Two dice at 3v and 1000mA would function as a single die of 6v at 1000mA.
Wiring in parallel, you use the forward voltage of one die, but the current is added up. Two dice at 3v and 1000mA would function as a single die of 3v and 2000mA. Calculate your resistor values accordingly.

There are good times to use both methods. If you only have a single li-ion cell (3.7v), then you lack enough voltage to run any two dice in series. Parallel is your only option in this case. If you are using a sound board that limits you to a single cell solution (NB, Prizm, PC with single cell hack), then parallel is mandatory. Parallel wiring is also good for color mixing. You can adjust the current to each die individually if you are wiring in parallel, to get that perfect color shade you want.

In series, you will need a higher voltage power source. Typically this would be a 7.4v li-ion pack (or 6v alkaline pack). This works well with the higher end sound boards like the Petit Crouton or Crystal Focus. The advantage of series wiring is that the LEDs only need a single LEDs worth of current, which directly affects your runtime. Two LED dice in series will run twice as long as two dice in parallel. The downside is that you can't fine-tune your color mixes. Each LED will get the same amount of current. This is not a problem if your dice are the same color.

In parallel, it is good practice to give each LED it's own resistor. There are cases where it's not mandatory, but you're always safe putting one on there.

[qaos]

Thanks SS. This was actually very informative and useful.
As I plan to do some single colored sabers (2 dies same color) and a color mixing (purple) saber.

As it stands, it sounds like I will probably be doing parallel for all of them, (either faster on the single color, or required for the mixing)

Now just waiting for parts to ship... so more time to read/watch/understand more.

Again, Thanks
Darth Qaos
(pronounced "chaos")

[Silver Serpent]

Good luck with your builds, and welcome to the forums!