Pretty much ALL of the standard (so called) "5W" LEDs are driven at 750mA/3V, you can even look up the specs for your typical Epistar/Epiled grow light LEDs. And 750mAx3V, well, is 2.25W. Now calculate 60 LEDx = 135W, which is exactly the actual power draw of those "300W" lights. TBH I don't even have an idea WHERE the "300W" come from, this especially also since actual 5W epistar/epiled LEDs don't even exist!
Now let's do some math based on REAL NUMBERS, not what some vendors says:
Let's look at the real luminous flux of the actual LEDs
MarsHydro "300W":
14x Blue (12 Royal Blue 50lm, 2 Bright Blue 50lm)
33x Red (17 Bright Red 80lm, 16 Dark Red 50lm)
13x White (W.White, 260lm)
Note I used the max. lm output here.
14x50lm= 700lm
17x80lm + 16x50lm = 2,160lm
13x260lm=3,380
== 6,240lm (if we'd drive them at MAX)
Now CREE CXB3590, 3500K, 36V, driven at 2,400
= 12,000lm (if we'd drive them at MAX)
While luminous flux is of course a silly, relatively pointless metric (it depends on colors, green for example has more lm flux than say blue or UV - because different colors are perceived as "brighter", some colors like blu2 "darker", at least it is actual numbers and not fantasy numbers)
So from that calculations alone I conclude that ONE CREE CXB (at 36V x 2,4A= 86W) light has twice the Lumen of one 300W light with 60 LEDs.
Now let's under-drive the lights, as is usually done. I mean we KNOW the Epiled "5W" lights are underdriven and MH somewhere states somewhere that the avg. LM of the MH 300W is 4377 lms.
This makes sense when we know that the MAX possible lumens is 6,240lm
If we underdrive the CREE CXB, instead of 2.4A to 1.4A, we're getting roughly 8000lumens.
So, REAL numbers:
Grow light with 60 Epistar leds: 4,377lms at 135W (32,4lm/W)
CREE CXB: 8,000lms at 50W (160,0lm/W)
I am realizing this math might be flawed, but it shows me that one CXB CREE is about twice as bright (looking at lumens) as one 300W light and FIVE times more efficient if we look at lms per watt.
Looking at my own setup:
2x300W Epistar LED grow lights vs. 4x CREE CXB COB:
8,754 lm vs 37,700 lm (because I will run them at 1,6A each) = 4,3x more lumens at about the same total wattage/operating cost.
Differently spoken: Say, if you buy (or build) an "expensive" light with CREE COBs, what you spent more over a "cheap" light with Epistar "5W" chips you will likely have made back in a very short time in energy savings (and bigger yields), so ultimately the CREE is a *way* better deal overall.
Now let's do some math based on REAL NUMBERS, not what some vendors says:
Let's look at the real luminous flux of the actual LEDs
MarsHydro "300W":
14x Blue (12 Royal Blue 50lm, 2 Bright Blue 50lm)
33x Red (17 Bright Red 80lm, 16 Dark Red 50lm)
13x White (W.White, 260lm)
Note I used the max. lm output here.
14x50lm= 700lm
17x80lm + 16x50lm = 2,160lm
13x260lm=3,380
== 6,240lm (if we'd drive them at MAX)
Now CREE CXB3590, 3500K, 36V, driven at 2,400
= 12,000lm (if we'd drive them at MAX)
While luminous flux is of course a silly, relatively pointless metric (it depends on colors, green for example has more lm flux than say blue or UV - because different colors are perceived as "brighter", some colors like blu2 "darker", at least it is actual numbers and not fantasy numbers)
So from that calculations alone I conclude that ONE CREE CXB (at 36V x 2,4A= 86W) light has twice the Lumen of one 300W light with 60 LEDs.
Now let's under-drive the lights, as is usually done. I mean we KNOW the Epiled "5W" lights are underdriven and MH somewhere states somewhere that the avg. LM of the MH 300W is 4377 lms.
This makes sense when we know that the MAX possible lumens is 6,240lm
If we underdrive the CREE CXB, instead of 2.4A to 1.4A, we're getting roughly 8000lumens.
So, REAL numbers:
Grow light with 60 Epistar leds: 4,377lms at 135W (32,4lm/W)
CREE CXB: 8,000lms at 50W (160,0lm/W)
I am realizing this math might be flawed, but it shows me that one CXB CREE is about twice as bright (looking at lumens) as one 300W light and FIVE times more efficient if we look at lms per watt.
Looking at my own setup:
2x300W Epistar LED grow lights vs. 4x CREE CXB COB:
8,754 lm vs 37,700 lm (because I will run them at 1,6A each) = 4,3x more lumens at about the same total wattage/operating cost.
Differently spoken: Say, if you buy (or build) an "expensive" light with CREE COBs, what you spent more over a "cheap" light with Epistar "5W" chips you will likely have made back in a very short time in energy savings (and bigger yields), so ultimately the CREE is a *way* better deal overall.
Last edited:
A person who buys those lamps is not necessarily "stupid".
).
