I love LED's. I dunno why. I just do. As they were being developed and used I've always been fascinated with them. I guess it's like a bug to a bug light. I've read lots of the DIY builds on a lot of different sites specific to many different plant species and even aquaculture. I've followed the threads here. Here's what I'm trying to do and the questions I have.
I grow pepper and tomato seedlings up till I plant them outside. I use 18"x48" T8 6 tube lights that I get at HD and they cost approx $110 to get up and running. $120-$125 if I don't have a power cord to rob the end off of. They're rated output is 17,069 Lm and use 2.02a. The Phillips bulbs I use are 6500K CRI 82 32w 2750 Lm. I'd like to build a fixture the same size since that's what I'm set up for and it fits my 1020 tray layout nicely. I'd also like to make something else to light my overwintering citrus instead of a 400w MH which will be different in size and shape but something I'd build after I get the peppers taken care of 1st.
Using numbers that smokemaster has shared on THP as a reference I made some general calculations. Keep in mind I realize the figures for T8's and LED's are not in stone numbers but we have to start somewhere. Using 1w LED's putting out 80 Lm I'd need approx 212.5 LED's to have equal lumens. 212.5 1w LED's would use approx 1.93a. Using the standard volts x amps = watts calculation. So far our numbers are pretty close between T8 vs. LED. Now smoke has stated he likes to use 50+ LED's in a 16"x8" area. Which when expanded out for my desired area would use 337.5 LED's using approx 3.06a. That would give me 27,000 Lm. So on the surface it would seem to be a wash. Not saving any money on electricity usage in the one example. Using a bit more in the other. In the first example my light output is equal. In the second example it is more.
The point that using just raw numbers doesn't address is the quality of light from the LED's. I understand that of the 17,069 Lm the T8 puts out not all of it is light my plants need/use. So trying to equal out the output may not be a valid idea. Maybe using just the wavelengths the plants need lowers the total lumens I need to have my DIY unit puts out. Of course to me lighting is something I prefer to have too much of vs. too little. So my amp usage and lumen guestimates is an apples to oranges comparison.
Also a consideration to take into account is cost of the build. No way is it going to be more cost effective to build a LED unit vs. what I can get the T8's up and running for. That is unless I can buy 1w stars for a quarter apiece or so. Also the price of drivers, power supplies, and the aluminum structure. I would probably buy from a supply house. Too many shaky 'el cheapo China sellers on the 'ol bay. This is not a cost is not an object or a cheap as possible build. I prefer quality parts going into a long term investment. I understand there are more powerful LED's than the 1w I'm using as an example. I don't want to have to resort to heatsinks and fans to keep the mess cool. I like the idea of the aluminum mounting plate or frame passively cooling the lights. Also, I like the mounting of the stars. I'm not interested in drilling a bazillion holes to mount all of the LED's.
Soooooo. Long winded what I'm really saying is this. I'm wanting to build a 18" x 48" unit. How many LED's is reasonable? Ratio of red vs. blue? I'll have a few white in there to allow plant inspection & viewing. What are preferred brands of LED's and drivers? I'd like to make this light just to see how well my plants respond. If it's not too crazy in time and money I'd make a few more to take the place of the extra lights I need down the road. Thanks for reading the long post. I'd love to hear some other ideas or thoughts on this. Did I mention I love LED's...............................
I grow pepper and tomato seedlings up till I plant them outside. I use 18"x48" T8 6 tube lights that I get at HD and they cost approx $110 to get up and running. $120-$125 if I don't have a power cord to rob the end off of. They're rated output is 17,069 Lm and use 2.02a. The Phillips bulbs I use are 6500K CRI 82 32w 2750 Lm. I'd like to build a fixture the same size since that's what I'm set up for and it fits my 1020 tray layout nicely. I'd also like to make something else to light my overwintering citrus instead of a 400w MH which will be different in size and shape but something I'd build after I get the peppers taken care of 1st.
Using numbers that smokemaster has shared on THP as a reference I made some general calculations. Keep in mind I realize the figures for T8's and LED's are not in stone numbers but we have to start somewhere. Using 1w LED's putting out 80 Lm I'd need approx 212.5 LED's to have equal lumens. 212.5 1w LED's would use approx 1.93a. Using the standard volts x amps = watts calculation. So far our numbers are pretty close between T8 vs. LED. Now smoke has stated he likes to use 50+ LED's in a 16"x8" area. Which when expanded out for my desired area would use 337.5 LED's using approx 3.06a. That would give me 27,000 Lm. So on the surface it would seem to be a wash. Not saving any money on electricity usage in the one example. Using a bit more in the other. In the first example my light output is equal. In the second example it is more.
The point that using just raw numbers doesn't address is the quality of light from the LED's. I understand that of the 17,069 Lm the T8 puts out not all of it is light my plants need/use. So trying to equal out the output may not be a valid idea. Maybe using just the wavelengths the plants need lowers the total lumens I need to have my DIY unit puts out. Of course to me lighting is something I prefer to have too much of vs. too little. So my amp usage and lumen guestimates is an apples to oranges comparison.
Also a consideration to take into account is cost of the build. No way is it going to be more cost effective to build a LED unit vs. what I can get the T8's up and running for. That is unless I can buy 1w stars for a quarter apiece or so. Also the price of drivers, power supplies, and the aluminum structure. I would probably buy from a supply house. Too many shaky 'el cheapo China sellers on the 'ol bay. This is not a cost is not an object or a cheap as possible build. I prefer quality parts going into a long term investment. I understand there are more powerful LED's than the 1w I'm using as an example. I don't want to have to resort to heatsinks and fans to keep the mess cool. I like the idea of the aluminum mounting plate or frame passively cooling the lights. Also, I like the mounting of the stars. I'm not interested in drilling a bazillion holes to mount all of the LED's.
Soooooo. Long winded what I'm really saying is this. I'm wanting to build a 18" x 48" unit. How many LED's is reasonable? Ratio of red vs. blue? I'll have a few white in there to allow plant inspection & viewing. What are preferred brands of LED's and drivers? I'd like to make this light just to see how well my plants respond. If it's not too crazy in time and money I'd make a few more to take the place of the extra lights I need down the road. Thanks for reading the long post. I'd love to hear some other ideas or thoughts on this. Did I mention I love LED's...............................