I've been a lurker for a long time. Started watching
@Growmau5 videos about a year ago. Great inspiration. Then I saw the build by Jorge on the front page of this thread and wanted to build something similar.
I built a light using
four CLU048-1212C4-403M2K1 cobs
Moduled 9980-B heatsinks
HLG-120H-C1050B driver
Ideal 50-2204CT holders
$140 before wire, aluminum, shipping.....
Its bar style just like
@OldGrower (hadn't gotten past the first page until yesterday). 10" spacing on the cobs using 3/4" aluminum channel, 1/8" thick (does the job but would have preferred 1/4" thick, couldn't find any).
The Citiled cob simulator shows each cob pulling 36.8 w @ 1050ma, Tc=50, so 147.2 watts total. Before I added the potentiometer to dimming lead my kill-a-watt read 163 watts. After I wired up the dimmer I got the same reading 163 watts, is this right? I thought adding the dimmer would limit the light by 10 watts. Also the light dims down to 7.7 watts. I thought I needed to add a low limit resistor (10k ohms) do prevent the light completely shutting off but apparently not. I've looked around but simply don't understand how the driver operates.
Meanwell's pdf shows 155.4 watts and 148V for the driver. Can someone help me understand why my kill-a-watt is reading 163 watts? Is it ok that its over the 155 watts? I just don't want to have an unsafe setup that is over driven. Also the driver is 94% efficient but It appears I'm only getting 90-92% depending on emitter temperature. Is this normal, is my math off? Can I do something to improve this or is it because of my combination of cobs and driver.
Needless to say I am amazed at the par numbers I am getting. Currently running at 110 watts which is just over 700ma after efficiency losses right (24.2/.92)*4=105.2w)?
Thanks to Robin, Bobby, and Supra for all the graphs and spreadsheets that helped me grasp the math with cobs. Can someone check my PPF at 700ma, I'm guessing its around 231? Thanks