Hey all,
I'm putting together a DIY LED COB lighting build, and I just want a sense check on my passive heat sink plans. I followed ledgardener.com's advice on calculating requirements, however the heat sink he used looks to be over £20 each - so my 4 lights will need £90 worth of cooling! That seems a little excessive and I don't want to be throwing money away.
Build Plan:
I'll be using 4 x Cree CXB3590 [CXB35900N0BDB40E] which should be a 'DB' bin, and I will be running these at 1.4 amps, giving 50 Watts / light. Assuming 50% efficiency that means I have 25 heat watts to deal with.
Heat Watts : 25 degrees C
Interface Resist 0.5 degrees C
Max Case Temp : 85 degrees C
Ambient Temp : 25 degrees C
Case - Ambient : 85-25 = 60 C
RC-a : 60 / 25 = 2.4
RC-b : 2.4-0.5 = 1.9
So as I understand it, I can use any heat sink with a thermal resistance lower than this figure right? So I can use for example this one (below) which is only £3.91 each? if so - that's a massive saving, but obvs I don't want to melt £140 quids worth of COBs so would really appreciate a sense check.
Many thanks in advance!
Heatsink:
Universal Rectangular Alu, 1.65K/W, 75 x 88 x 35mm
I'm putting together a DIY LED COB lighting build, and I just want a sense check on my passive heat sink plans. I followed ledgardener.com's advice on calculating requirements, however the heat sink he used looks to be over £20 each - so my 4 lights will need £90 worth of cooling! That seems a little excessive and I don't want to be throwing money away.
Build Plan:
I'll be using 4 x Cree CXB3590 [CXB35900N0BDB40E] which should be a 'DB' bin, and I will be running these at 1.4 amps, giving 50 Watts / light. Assuming 50% efficiency that means I have 25 heat watts to deal with.
Heat Watts : 25 degrees C
Interface Resist 0.5 degrees C
Max Case Temp : 85 degrees C
Ambient Temp : 25 degrees C
Case - Ambient : 85-25 = 60 C
RC-a : 60 / 25 = 2.4
RC-b : 2.4-0.5 = 1.9
So as I understand it, I can use any heat sink with a thermal resistance lower than this figure right? So I can use for example this one (below) which is only £3.91 each? if so - that's a massive saving, but obvs I don't want to melt £140 quids worth of COBs so would really appreciate a sense check.
Many thanks in advance!
Heatsink:
Universal Rectangular Alu, 1.65K/W, 75 x 88 x 35mm