Newbie needs help with first build

[parthitis]

Thanks so much for the help everyone!

I got some 18 gauage wire that i'm going to use instead and I got the U channel for fairly cheap. Just waiting for heatsink tape to be delivered now..

I re-checked the numbers on the strips. Turns out the strips warm up to reach a much higher amperage. One strip runs around 1.71A (max I saw was 1.73) and another one runs closer to 1.75A (max I saw was 1.77). Also, I double checked the input voltage. Checking across the wires where they contact the strips, I was reading 48.2. Reading the voltage at the connectors on the other end of the strip it was 47.5V. Sounds much better right? Now, the question is, should I downgrade the voltage, or leave it as is?

Also, just for clarification, I'm using a constant voltage driver, not constant current.

[Ted]

Thanks so much for the help everyone!

I got some 18 gauage wire that i'm going to use instead and I got the U channel for fairly cheap. Just waiting for heatsink tape to be delivered now..

I re-checked the numbers on the strips. Turns out the strips warm up to reach a much higher amperage. One strip runs around 1.71A (max I saw was 1.73) and another one runs closer to 1.75A (max I saw was 1.77). Also, I double checked the input voltage. Checking across the wires where they contact the strips, I was reading 48.2. Reading the voltage at the connectors on the other end of the strip it was 47.5V. Sounds much better right? Now, the question is, should I downgrade the voltage, or leave it as is?

Also, just for clarification, I'm using a constant voltage driver, not constant current.

Im glad this is working out for ya! If you’re good with the amount if light coming out, thats all that matters.

[parthitis]

Awesome! Glad to hear it.

Now that I have the led strips, I've got some mechanics questions:

What height above the plants should the led strips should be? How wide can the LED strips throw? I don't have a light meter of any kind, and I'm trying to figure out just how many 4" NFT channels one strip could cover.

Also, Has anyone tried "water-cooling" their led strips? I realized that even with the aluminium U channel, the strips still run pretty hot. With my setup in the basement, I was wondering about possibly routing my nutrient solution tubing through the aluminium u channel to both warm up the solution and cool the channel/led strips. What are your thoughts on this?

[Ted]

What are ya growing? And how many 4’ nft tubes and 4’ strips are we talking about. Id be very curious to see a diagram or some pictures.

You can put a single strip almost right on top of your plants. Probably a couple of inches. The closer you put multiple strips, the more you’ll have to move them away.

Generally speaking, I think 40-50 watts per square foot of LM561C power is a good ceiling and most people should shoot for 40w per sqf. The HLG 550 is 510 watts and covers 16 sqf (4x4) or 32w per sqf, although I think that still leaves alot to be desired in the corners and the outer foot of the 4x4.

[parthitis]

I'm just growing mostly lettuce and herbs at the time. I have 2 of the 4' strips and I'm trying to figure out how many 5ft (4ft really after dead space subtraction) 4" NFT tubes I can use with these 2 strips. I was thinking maybe 4-5 of the tubes with the Led strips hanging above them? Essentially with the led strips running parallel with the tubes. Theoretically I guess the area would be 4ft x 1-2 ft. How wide do you think I can go with these 2 strips that I have? That would determine how many NFT tubes I can run under the lights.

Thanks again for all of your help!

[Ted]

I'm just growing mostly lettuce and herbs at the time. I have 2 of the 4' strips and I'm trying to figure out how many 5ft (4ft really after dead space subtraction) 4" NFT tubes I can use with these 2 strips. I was thinking maybe 4-5 of the tubes with the Led strips hanging above them? Essentially with the led strips running parallel with the tubes. Theoretically I guess the area would be 4ft x 1-2 ft. How wide do you think I can go with these 2 strips that I have? That would determine how many NFT tubes I can run under the lights.

Thanks again for all of your help!

I'm glad to help! Its hard to guestimate this. Someone asked a question today about how many strips you'd need to get 1000PPFD, and dont know of a reliable way to calculate that. For lettuce and herbs, the lighting requirement is going substantially less than 1000PPFD, probably somewhere around a couple hundred. You could buy a Lux meter for $20 and use this formula PPFD=Lux/1000*15 to calculate the PPFD. Its a very rough conversion, but it might be helpful. Id hang the lights and test it with a meter to see how far apart you could get them with acceptable PPFD measurements.

[parthitis]

Hey thanks for the help!

I was really trying to avoid buying a meter but I finally bit the bullet and ordered one. Do you know of any good resources where you can find the best lux/par/ppfd/dli values for growing different types of plants? It would be really helpful to have on this site as well! I'm still trying to wrap my head around how much light my plants need and if my set up is enough..

Also, my setup seems to be comparable to the QB288 quantum board in terms of number of leds and wattage, if that helps with getting a better sense of light coverage..

[LEDG]

This is the best document I’ve seen so far for DLI values: https://www.extension.purdue.edu/extmed ... -238-W.pdf

[Strelok]

I was really trying to avoid buying a meter but I finally bit the bullet and ordered one.

For science (might as well use it since you got it, lol), could you post your Lux measurements:

• 6" below and in the center of your build
• 12" below and in the center of your build
• 12" below and 6" away from the center of your build (more into the dark), with the face of the light meter probe aiming straight up to the ceiling (not at the lights)
• 12" below and 12" away from the center of your build (more into the dark), with the face of the probe aimed straight up

I'm doing the same thing as you are and want to have a benchmark for my build to hit