So... here's version 3.
As some of you know I made a big purchase of 250x Citizen CLU046-1212 COBs. It was always my intention to run the chinese COBs for a couple of months to make sure the water cooling worked before investing in some more expensive/efficient COBs. I had intended on getting started in about a month's time but the opportunity came up to get the citizens for cheap so I took it earlier than expected.
My intention was to have units of 600w drivers with 30 COBs each. 3x units per 8x4 tent. 90 COBs per tent.
At the moment it's pretty hot during the day so I'll be running only 2x 30 COBs until mid September.
So here's version 3. Each unit took about 2 hours to upgrade from the version 2 units I posted at the start of this thread... which isn't too bad
I used aluminium angles to minimise the flexing I previously had going on.
The old COBs were removed with a razor blade, they came off pretty easily. The new COBs were stuck directly to the water blocks with Arctic Silver Thermal Advesive after a cleaning with isopropyl alcohol.
Here's a pic of one of my tents currently:
COB surface temp is 46C, water temp out of the radiator 30C, water temp going in to the radiator 38C, floor temp 26C, canopy temp 30C.
I know it looks like some COBs are much hotter than others but really it's just a difference of a degree or two which shows up dramatically due to camera sensitivity. Likely due to differences in how well the thermal interface was applied and maybe minor differences in COB voltage.
As I said I'll be adding another unit in the middle in about a month for 1800w top lighting. Then I'll add another 320w of side lighting per tent... that's the plan anyway!