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LED Power Draw Question

LED Power Draw Question

LED Power Draw Question

(OP)
Hey everyone, I am purchasing this LED head light for my motorcycle. This website gives 2 different wattages (low/high beam maybe?). I'm confused because non of those numbers match with ohm's law formula of 36 watts. Can someone explain this to me?

http://www.badwolflights.com/page10.html

Description from the website:

Power Draw: 12V / 55 W
Beam Pattern: Flood Beam/ Spot Beam
Light Output: High Beam 3200 lumens per assembly, Low Beam 1550 lumens per assembly
Color Temperature: 5000K, 6000K
Operating Voltage: 12V DC
Operating Amperage: 3A at 12V
Wattage: 45W
Waterproof Rating: IP68
Light: 15 CREE 3W LEDs
Housing Material: Black Aluminum
Lens Material: High Quality Clear Plastic
Hours: 5000+ Hours
Dimensions: L-4" X W-6" X H-4"

RE: LED Power Draw Question

The 12 Volt nominal voltage of the electrical system may be actually be near 15 Volts. 13.8 Volts was a standard auto voltage since the 60s. over the last few years I have seen several systems running higher than 13.8 Volts.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: LED Power Draw Question

I think most people in the auto industry uses 14 volts. In fact, this is where the so-called '42 volt' standard came from, as in '14 volts X 3', which was never adopted but was kicked around for years.

http://www.popularmechanics.com/cars/news/4226979

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

RE: LED Power Draw Question

LEDs have ancillary circuits that consume power, too.

RE: LED Power Draw Question

And it may be the equivalent light output to an incandescent lamp.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: LED Power Draw Question

"55w" is a typical rating for an original halogen incandescent headlight bulb. So the LED, which is more efficient, shouldn't remain as the same "55 watts". If it was, you'd probably be run off the road by angry and/or blinded drivers being blinded by the world's brightest LED.

It's likely close to the "3 A" specified.

You're right, the specs are all over the map.

RE: LED Power Draw Question

It is probably a variation on the theme used by manufacturers of compact fluorescent lamps - you see them with '60W' plastered all over the box, but what they really mean is that their 13W lamp put out about the same light as a 60W incandescent.

RE: LED Power Draw Question

"the same light" usually referring to the visible portion of the output, with some optimistic adjustment for visibility as a function of wavelength.

Jay Maechtlen
http://www.laserpubs.com/techcomm

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