BonjourI'm looking for a cheap alternative for the alpine 11 plus. New egg only has three in stock and I'm needing 8 of them, and not wanting to pay more from other retailers. I'll be driving the v29's at 106w. What heatsink would work for actively cooling 2 v29 per sink?
Rosewill RCX-Z1I'm looking for a cheap alternative for the alpine 11 plus. New egg only has three in stock and I'm needing 8 of them, and not wanting to pay more from other retailers. I'll be driving the v29's at 106w. What heatsink would work for actively cooling 2 v29 per sink?
I think I've just about bought them out. Sorry.I'm looking for a cheap alternative for the alpine 11 plus. New egg only has three in stock and I'm needing 8 of them, and not wanting to pay more from other retailers. I'll be driving the v29's at 106w. What heatsink would work for actively cooling 2 v29 per sink?
One way to find heat watts -> multiply dissipation W * efficiency. That gives you PAR W. Subtract PAR W from dissipation W and you have heat W.How do you calculate heat watts from dissipation watts?
Also is there a formula for how much surface area per watt is required...is that heat watts or dissipation watts?
Then how do you calculate how much with active cooling and how much active cooling (1 fan or 2,3...)?
So you have about 210 heat Watts and ~720 PPFD. Great setup, in order to get as uniform coverage as possible you could stagger the COBs a bit. You could use one giant heatsink 8.46"X62" or you could break it up into 2 sinks 10"X28" each.Having troubles finding the right size heatsink for my setup.
I am trying for passive air cooled so no extra fans are needed.
I'll be running 8 CXB3070s, running 4 on a single HLG 18h c1400b 1.4a.
Trying to cover my 6' by 2' flowering canopy.
Great to hear.So you have about 210 heat Watts and ~720 PPFD. Great setup, in order to get as uniform coverage as possible you could stagger the COBs a bit. You could use one giant heatsink 8.46"X62" or you could break it up into 2 sinks 10"X28" each.
Not testing your numbers @SupraSPL more like testing my calculations lol But could he not use 10" x 26"? I know its only two inches and better to have more then not enough. Just want to make sure I have been doing calculations correct more then anything. On another note I had came up with 677 PPFD can you clarify your calculations so I can see where I might have went wrong?So you have about 210 heat Watts and ~720 PPFD. Great setup, in order to get as uniform coverage as possible you could stagger the COBs a bit. You could use one giant heatsink 8.46"X62" or you could break it up into 2 sinks 10"X28" each.
Here are my calculations for you to see @SupraSPL I would like to figure out where I went wrong so I can make proper calculations in the future lolSo you have about 210 heat Watts and ~720 PPFD. Great setup, in order to get as uniform coverage as possible you could stagger the COBs a bit. You could use one giant heatsink 8.46"X62" or you could break it up into 2 sinks 10"X28" each.
its saul good man, a great thing to double check our maths, I am notorious for "careless mistakes" always rushing through too much math since 1st grade LOL. Anyway, looks like your surface area is very close to my figure. What is the formula in Box F4 of your first sheet?Not testing your numbers @SupraSPL more like testing my calculations lol But could he not use 10" x 26"? I know its only two inches and better to have more then not enough. Just want to make sure I have been doing calculations correct more then anything.
F4 is G2/110 for total surface area / 110cm2/heat wattits saul good man, a great thing to double check our maths, I am notorious for "careless mistakes" always rushing through too much math since 1st grade LOL. Anyway, looks like your surface area is very close to my figure, but what is the formula in Box F4 of your first sheet?
Regarding PPFD, looks like you used AB bin and I used AD. Here is where my math came from, assuming CXB3070 3000K AD bin at 1.4A.
50W X 8 = 400 dissipation W
400 * .48 efficiency = 192 PAR W and 208W of heat
192 * .9 (lens/reflecter/scatter losses) = 172.8 PAR W / 12ft² = 14.4 PAR W/ft²
14.4 * 4.66 * 10.7 = 718 PPFD
208W of heat * 120cm²/heat W = 24960 cm² of heatsink surface area for passive cooling
He has 72" of width so if we take 6" of each end we get about 60" that should be covered by the heatsink, depending how close to the edges the COBs are mounted. The 8.46" X 62" is 24634cm², a bit less than the recommendation but should work well.
A pair of 10"X28" is 26,261 cm², slightly more than the recommendation but offers good spread and good opportunity for staggering. He could definitely tweak it a bit and with 26" pieces, The 10" is a bit cheaper/cm² and if it were me I would prefer the system in 2 pieces for adjustability and it works well as far as wiring, one driver and 4 COBs per heatsink. Then again if you have an even canopy, one heatsink might be a great way to go.
I see that now and will update my spreadsheet thank you.Gotcha, I usually recommend 120cm²/W of heat for passive cooling, 40 for active. The 110cm² figure is based on dissipation W, back when there wasnt such a large range of LED efficiency like we now have.