Tri Rebel Questions

[RobieRob]

IMHO these days...

THANK YOU!!! I always end up getting carried away with trying to do stuff for the kids. (and I enjoy making things complicated to learn) That's kind of the response I was looking for. I have no experience w/sabers, and limited w/LED's. YOUR knowledge and experience is solid. So ordering from TCSS seems like the way to go.

Do you know if Tim still stocks the GGW in the store? They're listed, but I haven't seen them in since I started looking at his site....

[Forgetful Jedi Knight]

THANK YOU!!! I always end up getting carried away with trying to do stuff for the kids. (and I enjoy making things complicated to learn) That's kind of the response I was looking for. I have no experience w/sabers, and limited w/LED's. YOUR knowledge and experience is solid. So ordering from TCSS seems like the way to go.

Do you know if Tim still stocks the GGW in the store? They're listed, but I haven't seen them in since I started looking at his site....

Normally, yes, that is a color that is typically carried. He may just be waiting on an order to be delivered. He can't sell what he doesn't have in stock.

[RobieRob]

Ok, great. I'll just wait until they're in stock and order that. Thanks for all the info. I have read that you can build these fairly durable, and I've seen videos on YouTube that show guys beating the hell out of them. Can a Soundboard take that abuse?

[Forgetful Jedi Knight]

Ok, great. I'll just wait until they're in stock and order that. Thanks for all the info. I have read that you can build these fairly durable, and I've seen videos on YouTube that show guys beating the hell out of them. Can a Soundboard take that abuse?

If you build the chassis that supports it well, they can.

[RobieRob]

Ok, so after getting a response from Tim verifying he will soon have the GGW in stock I have decided to wait and order from him as per everyone's suggestions. I really wanted to learn how to calculate for resistors rather than use any calculators, however, I'm running into some what of an issue. When I calculate for the tri-rebel (RRW) I get

(3.7(Vs)-2.8(Vf)/.7(A)=1.285xxx (I know this doesn't have to be exact, but just for general purposes here)

now to get watts I multiply 3.7(Vs) by .7(A) and get 2.59watts/LED

So, here's my questions; TCSS stocks these http://www.thecustomsabershop.com/22...istor-P11.aspx
which is the 2.2ohm 5watt resistors, which would slightly overdrive the reds when ran in series (at least I think),

or should I play it safe and get these http://www.thecustomsabershop.com/15...istor-P13.aspx
which is what the calculator suggests 1.5ohm 5watt (actually suggests 2watt, but I'll be running in series)

And finally, for the BBW, GGW, and White for FoC is it really necessary to have 1 ohm resistors, or can I leave them off with the 3.7 18650 battery? They all have a Vf of 3.5, but I lack experience to what you can and can not do. I have read (somewhere on here?) that the 18650 fully charged put off more like 4.2v??

Gosh, I know that was a lot. For someone to take the time to read that I am truly grateful. TIA

[Silver Serpent]

The 1.5ohm 5watt is fine for a Rebel Red. The 2.2ohm would be underdriving it, not overdriving it. The warm colored Rebels are not particularly favorable for overdriving (or at least they didn't use to be), and this includes such colors as Red, Red-Orange, Amber, and Deep Red. The cool colors overdrive just fine.

You will not be able to wire two dice in series and run them off of a single li-ion. When you wire up LEDs in series, you need to add their Vf values together. 2.8v + 2.8v = 5.6v and that exceeds the voltage of your battery pack. You will want to wire them in parallel instead.

For the BBW, GGW, and White, you can get by without the 1ohm resistors. They will eliminate the possibilities of thermal runaway on your LEDs, especially when running multiple dice, but they're not mandatory. Many of the professional sabersmiths will forgo using the 1ohm resistor in a setup like yours. It's a personal choice, and will not noticeably affect the brightness of the saber.

[Forgetful Jedi Knight]

Ok, so after getting a response from Tim verifying he will soon have the GGW in stock I have decided to wait and order from him as per everyone's suggestions. I really wanted to learn how to calculate for resistors rather than use any calculators, however, I'm running into some what of an issue. When I calculate for the tri-rebel (RRW) I get

(3.7(Vs)-2.8(Vf)/.7(A)=1.285xxx (I know this doesn't have to be exact, but just for general purposes here)

now to get watts I multiply 3.7(Vs) by .7(A) and get 2.59watts/LED

So, here's my questions; TCSS stocks these http://www.thecustomsabershop.com/22...istor-P11.aspx
which is the 2.2ohm 5watt resistors, which would slightly overdrive the reds when ran in series (at least I think),

or should I play it safe and get these http://www.thecustomsabershop.com/15...istor-P13.aspx
which is what the calculator suggests 1.5ohm 5watt (actually suggests 2watt, but I'll be running in series)

And finally, for the BBW, GGW, and White for FoC is it really necessary to have 1 ohm resistors, or can I leave them off with the 3.7 18650 battery? They all have a Vf of 3.5, but I lack experience to what you can and can not do. I have read (somewhere on here?) that the 18650 fully charged put off more like 4.2v??

Gosh, I know that was a lot. For someone to take the time to read that I am truly grateful. TIA

OK. Lets start at the beginning.

1. You are not going to be running reds (or any other color for that matter) in series using a single 3.7V battery. Wiring in series doubles the voltage you need. 2.8 * 2 = 5.6 which is way more than 3.7V.

2. You also seem to be using the MAX Vf for your calculations, instead of the typical Vf (which is what is normally used) think of is as the average Vf needed to run a particular die. The Vf of the RED seems a bit high to me, but since Luxeon say's that's what it is, I'll take their word for it.

3. The formula you used for your second calculation is also wrong. So, having said that, and using the proper values, lets do the calculations the right way.

Resistance = (Vf[battery] - Vf[LED]) / Current ==> (3.7 - 2.8 )/ 1.28 => 1.5 Ohm

Wattage = Resistance * Current ^2 ==> 1.5 * (.7)^2 => .63 Watt -- so call it 1 Watt (But you can use a higher wattage)

NOTE: ^2 means squaring the current.

SO, to run the REDs, you would need 2 - 1.5Ohm 1W resistors.

4. Regarding the White, you would need to put a resistor on it if you expect the LED to last for a while. assuming you are running that also at .7A, you can use a .5 Ohm, .25 Watt resistor.

[RobieRob]

Silver Serpent/Forgetful Jedi Knight=My heroes!!

Seriously guys, thank you for taking the time to lay all that out. I appreciate it. If this forum had brownie points, kudos, high fives, squirrely Q's, karmas or whatever I would definitely give you both some.

[RobieRob]

Because I have to run in parallel, can I have 1 - 1.5ohm 2 Watt resistor on the + line going to each Led pad? Or does each specifically need its own resistor?

[Forgetful Jedi Knight]

Because I have to run in parallel, can I have 1 - 1.5ohm 2 Watt resistor on the + line going to each Led pad? Or does each specifically need its own resistor?

Each red LED one needs it's own resistor. That's why I said you would need 2.