Remember that youd be buying an extra chip and heatsink with the Bs. So I doubt it will be cheaper to go that route..
Vero 29 B or C?
- Thread starter KushyMcKush
- Start date
Hybridway
Well-Known Member
135 ain't to bad. You sure it's not 48? Might be worth knowing seeing how you get asked allot of questions & there are a decent amount of people trying to get 100w out of there cob. I'm getting great results using 100w CXB's actively cooled w/ copper core sinks.
Sorry to ask stupid questions but I know you know Wazup & id like to get the correct answer. What's Tj mean? Seen it used in convo. & i'd like to always understand.
Gotta get at you after this harvest for some material. Still need to switch out cobs in my Hydroponics Hut & am going to build a light finally.
Photon Flinger
Well-Known Member
Well it is from the manufacturer and it is all theoretical math on paper that we are using so who knows. The upfront additional capital cost is worth it in my opinion but might not be to others. There are many different ways to get the light we need.
What I do know is that they grow plants really well. I think we can all agree with that.
Tj is supposed to represent the p junction where the gap is to create the electrical arc to produce the light. Most vendors provide a point on the package that is relatively close to representing the real temperature that you can measure. Once again +/- 5c is more than enough seeing as these chips are rated to run up to 125c.
CobKits
Well-Known Member
im just saying the simulator is completely wrong and does not match either the datasheet or how cobs behave in real world. mistakes happen.Vero C runs right along with other cobs like clu058 and cxb3590 at low currents, you will find no datasheet on earth that claims 240+ lm/W from a cob
yup most people who switch to good LEDs dont go back.
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CobKits
Well-Known Member
i doubt it. its attainable at 100W but you need a chip with more dies to be efficient at that wattage. cxb only has 144 dies like a citi1212. as great as crees dies are they still have their limitations like any when run hard, and they seem to lag behind others at high currents, likely due to the alumina ceramic cases which dont dissipate as well as aluminum
im sure. white leds at 40-45% are still bettter than HPS in both spectrum and efficiency.
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CobKits
Well-Known Member
Tj is the junction temp measured where the dies are connected, as photon said above it is the closest real measurement to diode temp. as opposed to more easily measured Tc, case temp of the chip which is measured on the chip itself. so theres thermal resistance from the diodes to the case, and then from the case to the heatsink
here is a page which explains Tj,Tc, Rj-c, etc really well
http://www.led-heatsink.com/LED_heat_sink_calculation_simulation_thermal_design.html
running soft these numbers converge. at 300 mA you can have 30C Tj, 28C Tc, 27C heatsink temp
at 3000 mA you can have 130C Tj, 90C Tc, 80C heatsink temp. thats all the resistance trying to get the heat from the chips dissipated
Photon Flinger
Well-Known Member
Leave the heat sinks for CPUs and use simple sheet aluminum. If you need bulky heat sinks for cooling then you are wasting electricity on heat that could be used to produce more light.
And yes we are all just playing with numbers that may or may not matter to plants.
Photon Flinger
Well-Known Member
Like I said earlier many paths often lead to the same destination. More cobs is the way to go if you want to get the most out of the wattage you have available.
Photon Flinger
Well-Known Member
If it makes you feel any better, I re-purposed some old blurples using the cases and even the drivers. Quick to set up, change out parts if needed and have lots of spares available.
Plus you can always add more in later.
klx
Well-Known Member
This is wrong. They run around 94W @ 1400mA and are perfectly fine passive on 140mm sinks with just the standard grow room air circulation.
Vero Cs are the fucking bomb, get them. I kept my HPSs just in case but after 3 COB runs they have been donated.
CobKits
Well-Known Member
sure they work, all the current chips are rated north of 140C Tj.. They would be a little more efficient with actives. you gain more light energy than the little fans consume (and they would bump up voltage a bit)
for some reason i forget they are 68V, i always think of them as 72V like he crees. their low voltage is def a bonus when stuffing them on drivers, quality chips. i also like to run my cobs hot-ish (75ish W) which is about as comfortable as i am with a 140mm passive
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