Resistor help with a ddriven cree p4 and 17670

[dmc888]

I just got done boring out my rc-f4 to fit a protected 17670 cell and have it direct driven with no resistor.

Do i need a resistor with a protected cell? I rather not fry the led.

Which one would be a good choice?

The light is brighter now, but gets pretty warm when I used it for ten minutes.

Thanks for any help.

 

[Drewfus2101]

http://led.linear1.org/1led.wiz

This is the site I use. I'm not too familiar with a Cree P4, but guessing at:

Source Voltage: 4.2V
Emitter Forward Voltage: 3.8V
Emitter Forward Current: 1000mA
Resistor: 1 ohm, 2W

I've bought a hand full of those from Newark. They are pretty cheap per resistor and have fast shipping. Good website too.