OK...so that's where NOT to get budget cobs...where did you get the ones you were happy with? Thanks.
So you get an idea, I just took some pictures of how this cob worked from 24v to 29.33v. You will see that there is barely noticeable if any patch work starting at 24v. So you know, LED diodes are made to work from 2.7 volts to 3.4 volts each, hence the specification 32-34v at max current, in this case. you will also notice the current draw as I'm showing the amount of current they use at those voltages.
This was done quickly just now for the show, and the water was not running through the heat sinks, that's why they draw more current when they get up to 29+ volts.
Under water they only draw 2.5Amps at 29.5v. Go figure, it's more efficient than pin fin heat sinks and big old extruded aluminum expensive junk. Might look cool but it's not what i'm going to do if i can squeeze more lumens by just running cooler and cheaper. LOL. some people just don't get it.
Since your interested, you can get a good deal on those liquid cooling sinks on
http://www.newegg.com/Product/Product.aspx?Item=9SIA3XT1NM7709&cm_re=Aluminum_Cooling_Block_For-_-9SIA3XT1NM7709-_-Product
yup $6.29 each, that's more like my cup of tea, cheaper than CPU aluminum heat sinks... LOL...works phenomenal. and as a reservoir any 30L to 40L container is enough, think Rubbermaid tub $10.
Anyhow here are the pictures, so you get an idea.
Here we go...
running at 24.01 volts,
It's not drawing enough current to move the meter...no patch work like those crap LOHAS leds... these babies are EPISTAR, made in Taiwan for all those Chinacob haters and CREE lovers... ... read about them and learn something, do the math most importantly.
Now since it's in the operating range for the diodes, it's now running at 27.03 V and drawing 0.56 Amps. or using about 15watts of power.
Here at 29.11V it's now getting warmed up, and pulling ~64Watts of power. Good deal, Extremely bright, lights up the entire room, I would hope so anyhow! LOL.
And here we go the sweet spot, 29.33v and 2.89 Amps, okay so yeah, like I said before you can do this under water cooling and it's pulling only 2.5 amps. In this picture, I have to reiterate, WATER is not flowing through the system. Just passively cooled for the demo. I would also like to make a note of the CRI, it's seems to be at least a minimum 80CRI, usually anything under that number comes in really fuzzy or blurry when you take a picture.
Hope you like my quick write up.
Happy Budding!