Handlobraesing
Banned
- Joined
- Feb 14, 2006
- Messages
- 2,724
I ask this, because I just transplanted a Luxeon III from a 3 AAA 3W flashlight into a 3D Dorcy 1W Luxeon.
The 3AAA 3W obvious have horrible battery life, because AAA batteries do not handle 0.8A of current so well. In a Brinkmann 3AAA 3W LED flashlight, the LED is direct driven from three series connected batteries and uses the battery bank as the ballast. The voltage across LED is around 3.3v and the current is 0.82A, which comes out to around 2.7W. Current is lower than the short circuit current of the batteries, because LED adds resistance and current is smaller than regulated 4.5v across the LED, because internal resistance of battery brings the voltage down enough to lower the current to 0.82A. The design basically exploits the internal resistance of AAA batteries to act as a ballast.
So, the same LED transplanted into a 3D Dorcy light and direct driven draws about 1.6A with fresh alkaline batteries. I used thermal compound on every thermal path and ensured the LED isn't getting too hot to touch, but am I still hurting the emitter?
White, blue and cyan are rated for maximum 1,000mA and red, amber, etc are rated at 1,400mA per spec.
The 3AAA 3W obvious have horrible battery life, because AAA batteries do not handle 0.8A of current so well. In a Brinkmann 3AAA 3W LED flashlight, the LED is direct driven from three series connected batteries and uses the battery bank as the ballast. The voltage across LED is around 3.3v and the current is 0.82A, which comes out to around 2.7W. Current is lower than the short circuit current of the batteries, because LED adds resistance and current is smaller than regulated 4.5v across the LED, because internal resistance of battery brings the voltage down enough to lower the current to 0.82A. The design basically exploits the internal resistance of AAA batteries to act as a ballast.
So, the same LED transplanted into a 3D Dorcy light and direct driven draws about 1.6A with fresh alkaline batteries. I used thermal compound on every thermal path and ensured the LED isn't getting too hot to touch, but am I still hurting the emitter?
White, blue and cyan are rated for maximum 1,000mA and red, amber, etc are rated at 1,400mA per spec.
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