so technically , your frames can handle up to 650 watts ish and still be within the right range? but of course , thats max and they would run hot but am i correct ?
So "technically" I am referring to the maximum current of each LM561C diode (200mA) multiplied by the voltage at that current (3V), multiplied by the number of diodes on each strip (48 ) = 28.8W. With 12 strips on each frame, the maximum wattage is 345.6W.
Originally I had each frame on a 240W driver for 480W total. This was too much for my 4x2 area, so I dialled them down until I found I could run both frames off a 320W driver at around 345W – which incidentally was 50% of the maximum current rating of each diode.
There is a maximum temperature rating as well as max current for each diode, so as long as you don't exceed that temperature, you can run your LEDs as hard as you like. The trick with LEDs is they can be run up to and over their maximum rating . . . as long as you can keep them cool. Cooling increases efficiency and diode life.
Samsung F-Series strips run their diodes very close together – so they will heat up more for the same current. However, H-Series strips have their diodes spaced quite far apart, so will not heat up as much at the same current. (F-Series have aluminium PCBs, H-Series have FR-4, so the F-Series have better thermal dissipation to make up a little for the close diode spacing.)
So it simply comes down to cooling. At 480 watts (240W per frame), the frames were hot to touch. At 345W (175W per frame) they ran only slightly warm. At 650W they would have run very hot, but with a fan blowing over the U-channel to duct the heat away, they would have probably been OK. If I had a better heatsink design, they definitely would have been OK.
But at that wattage, the LEDs would not have been very efficient and would have created a lot of heat inside a small area (as well as producing way too much light).
A side-effect of running each strip at only 50% is that the plants could grow into the frame with very little damage.
The moral of the story is, you need to find a "happy medium" between diode cost vs efficiency vs heatsinking vs light. More diodes at a lower power is more efficient, but more expensive. Fewer diodes at a higher power are less efficient and need good heatsinking, but may or may not be cheaper – as you also need to factor in the cost of proper heatsinking.
TLDR
So what you're really asking me is how hard I would run those frames? The answer is I would pair each frame to a 240W driver and run them at up to 270W per frame (a HLG-240H driver will output anywhere from 260-280W). That would be enough to cover a 3'x3' with each frame (just), but would be better suited to a 2.5'x2.5'. Or do what I did and cover a 2'x2' dialled down to 170W or so.
