tri-rebal and the pcv3

[garymorris2]

when using a tri-rebal g/g/w with a PVC3, if i wire the two green in parallel will ineed a resistor out side of the board and if so could i wire them in series to not use a resistor

[erv]

PCv3 has an onboard current driver, if you wire your LEDs on it, you won't need resistors.
new rebels have low Vf allows to wire the 2 greens in series without sacrifying the runtime, and running a lower amp, cooler temps with still a real current control and regulation

[KamiKuzi]

You never wire LEDs in parallel! LEDs require a certain current flowing. Example: If you wire 2 LEDs with max 700mA in parallel and set the PC to 1,4A so each LED should get 700mA. But there's always a certain fluctuation in production of LEDs and you can't control how the current is split up so one of them will probably be overdriven. They take what they get. One will have more current than the other and eventually burn up. Then the other will get the full 1,4A and burn too.
Sorry, I like explaining stuff...  ::)

Just wire them in series if you're using a 7,4V battery. There's no need for a resistor anyway. You only need resistors for direct drive to lower the voltage and current. PC and CF main channels are current controlled so they take care of all that.

[garymorris2]

thank you my friends!! this helps very much! :)

[garymorris2]

PCv3 has an onboard current driver, if you wire your LEDs on it, you won't need resistors.
new rebels have low Vf allows to wire the 2 greens in series without sacrifying the runtime, and running a lower amp, cooler temps with still a real current control and regulation

i had another question, with the on board power xtender if i use a 1ohm 2w resistor could i use the foot prints or bridge the foot prints and put the resistor outside of the board ?

[LUMINARA UNDULI]

You never wire LEDs in parallel! LEDs require a certain current flowing. Example: If you wire 2 LEDs with max 700mA in parallel and set the PC to 1,4A so each LED should get 700mA. But there's always a certain fluctuation in production of LEDs and you can't control how the current is split up so one of them will probably be overdriven. They take what they get. One will have more current than the other and eventually burn up. Then the other will get the full 1,4A and burn too.
Sorry, I like explaining stuff...  ::)

Just wire them in series if you're using a 7,4V battery. There's no need for a resistor anyway. You only need resistors for direct drive to lower the voltage and current. PC and CF main channels are current controlled so they take care of all that.

This is completely incorrect.  LEDs are wired in parallel all the time.  It is the way the majority of LEDs in our industry are wired today, in fact.  In parallel, you can control the current to each die through resistors, buckpucks or, if you have a board that does it for you like CF, through the board.

[XsaberX]

PCv3 has an onboard current driver, if you wire your LEDs on it, you won't need resistors.
new rebels have low Vf allows to wire the 2 greens in series without sacrifying the runtime, and running a lower amp, cooler temps with still a real current control and regulation

i had another question, with the on board power xtender if i use a 1ohm 2w resistor could i use the foot prints or bridge the foot prints and put the resistor outside of the board ?

either is fine

[KamiKuzi]

I'm just curious: how did you get the value of 1Ohm. That seems a bit too small!!!

Assuming you use a 7,4V battery and want to use it for the white die (usually around 3,2V) via onboard PeX I get over 4Amps with 1 Ohm and almost 18W power dissipation on the resistor!


You should check your calculations!!!

And another thing:

This is completely incorrect.  LEDs are wired in parallel all the time.  It is the way the majority of LEDs in our industry are wired today, in fact.  In parallel, you can control the current to each die through resistors, buckpucks or, if you have a board that does it for you like CF, through the board.

There's a little misunderstanding here.
There are no LEDs wired in parallel. As you said: You control the current through resistors or buckpucks or.... Which are in series to each die. The overall circuits are in parallel of course. But there are no LED dies in parallel. You always have 1 regulator (resistor, buckpuck, currentdriver, etc) in series with 1 LED die. But you never have i.e. one resistor in series with 3 LED dies (in parallel). Well of course you CAN do it. And it will work, but the chance of frying all dies is pretty high.
Sorry for the off-topic. Just want to get this straight...

[erv]

that 1 ohm value seems really low indeed

regarding leds in parallel, it happens all the time. Point above is legit as no LED / die have a perfectly matching Vf ensuring an exact 50-50 split of the current in each die, however, the manufacturing of the tri-xxx leds and the binning system allows to have them close enough to have a fairly even split.

from there, a single buckpuck or current regulator can perfectly limit the overall current that then gets naturally split between the 2 LEDs / dice and that works just fine. For totally different leds (colors), a heel / sole resistor is added on the weakest vf and even this allows to do custom color mix. It's been there for ages to produce purple with // wiring, and before the rise of multi channel current regulators (for sabers)

[garymorris2]

I'm just curious: how did you get the value of 1Ohm. That seems a bit too small!!!

Assuming you use a 7,4V battery and want to use it for the white die (usually around 3,2V) via onboard PeX I get over 4Amps with 1 Ohm and almost 18W power dissipation on the resistor!


You should check your calculations!!!

And another thing:

This is completely incorrect.  LEDs are wired in parallel all the time.  It is the way the majority of LEDs in our industry are wired today, in fact.  In parallel, you can control the current to each die through resistors, buckpucks or, if you have a board that does it for you like CF, through the board.

There's a little misunderstanding here.
There are no LEDs wired in parallel. As you said: You control the current through resistors or buckpucks or.... Which are in series to each die. The overall circuits are in parallel of course. But there are no LED dies in parallel. You always have 1 regulator (resistor, buckpuck, currentdriver, etc) in series with 1 LED die. But you never have i.e. one resistor in series with 3 LED dies (in parallel). Well of course you CAN do it. And it will work, but the chance of frying all dies is pretty high.
Sorry for the off-topic. Just want to get this straight...

the 1 ohm was the foc die , in the maual it said it would be ok but i am unsure

[Forgetful Jedi Knight]

You need to do the math for yourself - and not guess. Your (and KamiKuzi's) math are (both) inaccurate.