I don't know if this was discussed here before, the topic is too long now to read everything from beggining.
Anyway, I wanted to asked if someone every tried these Cree COBs bulbs. Here it goes:
http://www.ebay.co.uk/itm/10x6W-8X9W-12W-GU10-CREE-COB-LED-Light-Bulb-Downlight-spotlight-lamps-Dimmable-/141470120989?var=&hash=item20f046bc1d:m:mOHNP9EYlqt1Z6Il-IoeFCQ
We don't know for fact if it is Cree or fake, but it is a COB and that's better than SMD bulbs. It is shipped from UK, so I would say there's a higher chance of being a decent product comparing to those shipped from China.
It says 1100-1300lm per 12w bulb.
In the end I would pay 35$ for 120w and 11000-13000 lumens. Comparing to the 3070 I like the ideia of these bulbs because it is cheaper, easier to install, doesn't require active cooling and since it has a GU10 base type can be used to many other aplications. The fact that it doesn't require a fan pulling air is a plus plus for me for reducing noise.
In terms of efficiency it is worse than the 3070 for sure, but the difference isn't that significant.
The most generally used 3070 (Z2 I guess) has a output of max 7400lm when pulling 74w. That's 100 lumens per watt. The Cree bulb has a max output of 1300lm and pulls 12w, that's 108 lumens per watt.
The 3070 can be driven softer reaching higher efficiency, but you got the point. I'm planning a 100-150w grow set up but I don't want to break the bank, I see these two possibilities:
2 x Cree 3070 driven at 1.4A pulls 100w - 150$
10x Cree bulb pulls 120w - 35$
Based on the information provided the light output seems similar.
Any thoughts about this?