Quote Originally Posted by 53driver View Post
Ken,
You've done more work on/with lights than any three people I know, so your HO is valid in my book.
The "100 lumens per watt" number - what is the limiting feature there? Simply LED technology?

The Low Beam number (@ 14v) would have to be ~115 to get the 2400 lumens.
The High Beam number (@ 14v) would have to be ~150 to get the 4800 lumens.

I might almost buy into the 115 number. That's close enough to "~100" to make it palatable.
But to get to 150 lumens per watt sounds like complete technological revision or, as you mentioned, false advertising.
Unless their amp draw numbers are off.....

I'll be emailing SoCal with some specific questions.

As always, thanks for the lesson my friend.
Cheers,
Steve
Yes, Steve, the lumens/watt number is a function of technological development. CREE is probably the leader in this industry and has been offering LED's with an efficacy of 100 lumens/watt for some time now. Of course, this number continues to rise and, without looking it up, CREE has recently gone beyond that probably somewhere in the range of 125 lumens/watt. This number will vary with the particular LED and it also depends on how hard the LED is driven (a function of the current limiting design of the driver). Drive it too hard and life suffers. Due to that, I personally wouldn't want to count on anything over 100 lumens/watt and frankly, I'd be surprised if we even get that. As I've said many times before, most suppliers of LED's misrepresent the facts so we need to take, with a grain of salt, the color temp, the wattage, the lumens, and even the amp draw. I have a clip-on ammeter that I have used to confirm the amps and it has led to more than one "revelation". I suppose what's happening here is that when most of the LED suppliers are lying about their product, the remaining suppliers have to play that game as well. Otherwise, their specs will look weak by comparison. What I do put stock in are the specs listed by the manufacturer (not the supplier or seller). Once I know the particular CREE element being used in a bulb, I go to the CREE site to see what the true specs are. I do NOT rely on the supplier for that. Even then, the supplier may be lying about the CREE element in their bulb. It's indeed a tricky matter. In the end, maybe all we need to be concerned with is the quantity and quality of the light produced by a bulb. So, when we find one that performs well, we need to let others know which, more or less, is the thrust of this thread.