Cxb 3070 spacing.

L

lotus710

Member
Currently building a light i should of built a while ago. I just have a quick question since i cant find it anywhere. How far apart do i space the heatsinks? They are the 105mm pin heatsinks from HLG. Running the cobs at 1050ma. I was thinking around a foot but im not sure. Im using ledil angelinas. Thanks in advance
 
wietefras

wietefras

Well-Known Member
At 1050mA (36W) you'd need about 9 per square meter. Just divide the number of COBs you buy evenly over the space.

Wouldn't chose to use reflectors myself, but others seem to still use them.
 
wietefras

wietefras

Well-Known Member
lotus710 said:
Reasoning for no reflectors?
Click to expand...
They absorb a lot of light. Especially when they get a bit dirty which happens quite quickly.

Using reflectors you will lose between 8% and 10% of the light already on the reflectors themselves. Since they catch only the 20% of COB light which is emitted outside the 90 degree beam angle, I'd say you lose half of that light. You're better off just letting that light find it's own way towards the plants. Most of the light will travel directly towards the plants anyway since the COBs are spread out over the grow.

With reflectors you also have to hang the lights higher above the plants to get the same uniformity of light distribution. About twice as high as without reflectors. On the plus side that gives you a bit more space so you don't have to adjust the light upwards during veg, but it also means you incur more wall losses.

Malocan once measured the average PPFD in his 4x4 tent with and without reflectors. With reflectors attached the average PPFD was 629umol/s/m2 and without reflectors 744umol/s/m2. So that's 15% less light in a real live situation when using reflectors.
 
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