Interpreting Delivered Lumens

[jives]

My eye caught this on Ebay. . .a 4 lamp LED fixture, 72W, delivering 18,000 lumens. I understand the concept of delivered lumens vs. total lumens, so something seems fishy here. A 72W fixture may put out 7000-8000 total lumens (check out the company webpage, not just the Ebay page), so how can delivered lumens be double the total lumens?

http://www.ebay.com/itm/4-Lamp-LED-...000-Delivered-Lumens-72Watt-NEW-/262478403781

Is this just an advertising mess up or am I missing something?

 

[cybrdyke]

It's gotta be a typo. 18000 lumens/72 watts = 250 lpw, which is not realistic. It looks like these guys are building fixtures in their garage and trying to market them as something special. There's name brand stuff out there that is a better value.
Good luck
CD

 

[jives]

I'm thinking typo as well, but it is so glaringly obvious (pun intended) that it makes you wonder if they are using it on purpose to make folks click the link.

 

[cybrdyke]

I'm thinking typo as well, but it is so glaringly obvious (pun intended) that it makes you wonder if they are using it on purpose to make folks click the link.

Of course they are. Most folks dont understand what they're looking at when it comes to lighting. Should be a red flag for you.
CD

 

[Geobound]

The 18,000 lumens doesn't concern me, so much as the watts do.

I would suspect that the wattage should be more like 150 to get those values.

With that type of lamp I would expect to see something around 100 lumens/watt at the system level.

So roughly 2100 lumens per LED lamp, but since there is an overlap of "lamps" it actually decreases the total delivered package......so I would say a 4 light fixture would give you roughly 7600-8000 lumens based on the 72watts.

I am curious to know how they publish though?