Joined: 06 Nov 2009
Location: Waxhaw, NC
|Posted: Mon Jan 04, 2010 1:57 pm Post subject: In need of LED help
|I have a 18v worklight that I bumped while it was on and killed the bulb. This gave me an exc...err reason to upgrade to LED.
I found a SSC P7 LED on eBay that puts out some crazy light, 900lm @ 2.8 amps. I have a DC/DC regulator with an input range of 18-75VDC and an output of 5VDC @ 2 amps. My question is how do I make them play well together? I have ran some calculations and am not sure what value to plug in for the LED, 3.3, 3.6, or 4.2?
SSC P7 specs
Vf = 3.3VDC @ 1.4 amps: 3.6VDC typ: 4.2VDC max
If = 2800 mA
lm = 400 @ 3.3VDC: 700 @ 3.6VDC: 900 @ 4.2VDC
5V source and 3.3V across the LED = 0.85 ohms @ 3.4 watts using 2 amps
5V source and 3.6V across the LED = 0.70 ohms @ 2.8 watts using 2 amps
5V source and 4.2V across the LED = 0.60 ohms @ 1.6 watts using 2 amps
I have access to resistors up to 50W. It seems that for my application and enclosure size that a 5W is the biggest I can go.
Link to SSC P7