Question regarding multiple LEDs

[allburger]

Ok, so over the past year I've learned alot about electronics from this site and people that ive talked to. There is still one question that is yet to be answered. Its an easy one don't worry...

When you are running multiple emitters, lets say a 3 cree setup in a maglite, what do you want the input voltage and amperage to be.

The cree's all want 3.6 volts each, and lets say that you want to drive each at 1000ma. Does that mean that you provide 3.6v X 3 = 10.8v with 1000ma to each, or do you apply 3.6 volts to all three at 3000ma???

 

[allburger]

anyone??

 

[LukeA]

The first scenario.

 

[Greg G]

What battery arrangement are you planning to use?

For only 3 Crees, you could use 3 D NiMH batterries, and a boost converter, such as a Shark. The Shark will regulate current and step up the voltage to whatever is required to achieve 980ma, assuming you run the Shark at full output.

For this setup the Crees would need to be wired in series.

 

[LukeA]

There's also the option of using AMC7135-based drivers running in parallel each running a single emitter. That works well off of 3 series NiMH.

 

[Gunner12]

The first one(in series) would work better because each LED can have a different Vf. In parallel, the one with the lowest Vf will draw the most current, and that could cause the LED to be overdriven too much.

What battery voltage would you be using?

 

[TorchBoy]

you provide 3.6v X 3 = 10.8v with 1000ma to each,

No, to all three in series.