Member of the Month: July 2012, July 2014 - Nug of the Month: July 2012
Just remember, yield is not the only factor to look at when comparing LED's. Look at Lumen depreciation, most cheap LED chips last around 37,000 hours before losing 20% or more of their output, where most premium chips will only lose about 5% output around 67,000 hours. So consider that as well.Also keep in mind when the expensive led hype train gets going that one fancy pants $1000+ light might be better than a value priced Mars hydro, but it is not so much better as to justify the price. If it is 10% better at twice the price then that is not good (to me).
Or put it another way, whatever fancy light you get for $1000 or whatever - consider how much more yield you would get if you spent the same amount as the fancy light on several Mars hydro lights...
Also consider electrical efficiency. Lets say you have 2 lights, both same draw wattage but one is using cheaper chips and one is using premium chips. You may get about 1 1/2 to 2x as much light out of a premium chip vs a cheaper chip at the same wattage. For instance a TOP BIN 660 epistar chip puts out about 200mW @ 350mA, where a ToP BIN Osram 660 puts out around 400mW @ 350mA, therefore you are getting double the light output a the same draw.
Same goes for drivers within the LED itself.
So even though a light may be 1/2 price, it also only may last half as long, causing you to have to purchase 2 over the lifetime of a better light.