# Looking for someone’s time please. ( LED lighting questions)

Discussion in 'Lighting' started by Yesyes3000, Jun 29, 2019.

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1. Hi everyone I’m an just wondering if somebody’s can help me to understand the spec statts on led lights ? For example
• Forward Voltage 48V
• Drive Current typ 500ma, max 1200ma
• Lumens: Typ 4500 Lumens at 560ma, 9000 Lumens at 1.2A
• Cree or cri
• Other important info
I am really interested in understanding exactly what I’m looking at when it comes to led lighting and just growing lights. I found a page a few weeks ago that had some info but I feel like there is probably a good chance that someone here could break this stuff down for me and make it easy to understand. Thank you for you time . Truly grateful
Sincerely 3000

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2. #3
Last edited: Jul 3, 2019
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3. Forward voltage is the voltage required to turn an led on. The led will have a voltage range and not a specific number depending on what current level it is ran at. A slightly higher current level requires a slightly higher forward voltage but they don't move linear. The forward voltage of an led only changes 10-20% or so over it's operating current range.

Drive current type would be the current range you can drive that led at. Looks like from 500mA to 1200mA. A milliamp is 1/1000 of a full amp so 1200mA is 1.2amps. 500mA is .5amps.

Lumens is light output measured in a scale for human vision first made for cameras and film. It's giving you an efficiency range. 4500 lumens @560mA and 9000 lumens @ 1200mA

The first would be 8.04 lumens per milliamp. Second number is 7.5 lumens per milliamp. They should actually tell you what voltage the led runs @ 560mA to figure out how many lumens per watt each setting is. All the way dimmed and max current. At 560mA it would likely be running as low as 44 volts or so and 48 volts at 1200mA so it would skew those numbers further.

It just shows that the led is more efficient at 560mA then at 1200mA and a scale for that even though it's just two numbers. It's more common for an led manufacturer to make something called a flux bin efficiency chart that has voltage, current, lumens, umols, ect in the leds whole operating range. HLG has these on most of their board at the website.

Cree and CRI confuses me because cree is an led manufacturer and CRI is color rendering index. Basically what color they are similar to the K rating or temp rating of a light. Certain manufacturers use the CRI number and some use the K number. With K rating lower numbers are more red and higher numbers are more bluish. With CRI I'm not sure actually. I rarely see it. I would assume it would be the same with lower CRI being more reddish and higher CRI being more bluish.

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4. #5
Last edited: Jul 3, 2019
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5. To smoke sara above. High end SMD has been the best tech for like the last 8 years, white light has been better than blurple for the last 3-4 years. People in the grow industry have just been sold on marketing materials. A cree COB (or other brands) however can be better than some SMD.

Your COB takes 48V @ 500ma. 4500lm @ 560ma. So slightly less lumens at 500ma. 9000 lumens at 1200ma. You can drive it a maximum of 1200ma provided it is correctly heatsunk. Voltage will be slightly higher at 1.2A.

Cree is an American LED component manufacturer. They forge their dies in USA typically and final package in China. They are probably the cutting edge in high powered colored LEDs. They have the most efficient 660nm on the market right now.

The CRI is color rendering index. It is how closely it renders colors essentially compared to sunlight. CRI of 80 is standard these days unless you're talking about high bays. LEDs with CRI70 have bretter umol/j because the phosphors are doing less. If you look at the spectrum graphs they have sharper peaks and the red peak is to the left of the graph. CRI over 90 suffers big on lumens however lumens aren't important for growing. Some people have reported better results with higher cri however I don't necessarily buy in. I'd use CRI80

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