Backyard Aquaponics
A place to discuss aquaponics

Fastest growing? I'd guess a pea or bean of some sort?

Gah, can't find my soldering iron.

Just for the heck of it I bought one of those 168 LED grow lights off ebay. I am also going to build one using 1 watt LEDs and I will compare them. I bet the 5, 1 watt LEDs will beat the 168 led light hands down.

Went out and bought a new soldering iron. So now I have a red LED lamp!

I didn't have any circuit boards, and I didn't really want a small rectangle anyways, so I took a piece of drain PVC and cut it in half length-wise, and drilled holes for my components.

The first circuit I tried using a full bridge rectifier. One of my 4 bridge diodes promptly exploded, and I'm not sure why. So the next (working) circuit is just + input -> 1n4007 diode -> 3.6k 5 watt resistor -> 16 LEDs in series -> - input. Works just fine. No visible strobing, and it's not like the plants care.

I'll be adding strings in the coming days.

Did a bit of testing with the multimeter, and I'm getting a 38V drop across the 3600 ohm resistor, and 14V across 16 LEDs. So I'm getting 10mA (not 20) and each LED has a forward drop of .875V. At this rate, I'm going to need a lot more LEDs!

When you guys are talking watts, are you mixing up electrical watts with the output light watts? I.e. are you counting efficacy of the bulb to convert electrical power to light power? I'm pretty sure you have to derive the optical watts from the electrical watts and efficacy %.

In computer rendering nowadays the new renderers are using spectral rendering rather than just RGB color - they keep track of how many watts per meter at several nanometers, rather than just at three for RGB. This is a fun subject!

I am talking about electrical watts. Because, they say LED grow lights use 90% less power then a light like HPS. So a 100 watt HPS can be replaced with a 5 watt LED grow light, due the fact that LEDs do not waste power producing unused wavelengths.

Going to test some Led lights that just arrived on my basement system, Two red and two blue, pics in a few days.

The initial set up of the led bulbs, will redesign the spacing so they are closer together and directly over the grow bed. Wanted to get them up and running so I used a test fixture I had previously for CFI's.
The peas have been growing tall seriously lacking sun and I'm hoping, fingers crossed, some results will show up quickly.

John

How expensive were they? (if you don't mind me asking) and what sort of heat are they generating compared to say a compact fluro.

No heat at all really. As you can see from the picture one sets directly on the drain of the grow bed. The red were $22.75 each. The Blue $28.75 each.
They are (Par30 60 Led) PAR30-SB-120-E27-W-60, if that helps. Purchased from Best Home LED Lighting, sorry didn't provide the link.
Despertly hoping they will do the job. Seems odd to me that they would actually work but what the heck I'll test em out.
They are not advertised as Grow lights just flood lights, but an LED is an LED aint it?

I would arrange them into a square and mount them higher up to create a more even light source.

I agree Tim.

I got my L.E.D. grow light today. It has a 4:1, (red:blue) ratio. They are not the super bright LEDs, but with all 168 of them they crank out a lot if light.

I needed a grow light for here in the office anyway. Everyone here is asking me if Im growing pot, LOL..

It cost me about $34 with shipping. It would have cost me $8.40 to buy 168 LEDS and another dollar for a custom PCB to mount them all to and a couple more dollars for a light socket. So I could have made one for $12 not counting the two hours to etch a board and solder 336+ leads. Its hard to say if it would be worth saving $22 for two hours of my time. I guess it would be worth it if I was lighting a greenhouse because then you would be saving $22 per square foot(or two).

Oh, I got the data sheet on those purple duel wavelength L.E.D.s and the advertised wavelengths don't match the data sheet. Also, They produce a much wider spectrum of light so that would be wasted energy. So its a no go on those.

Hope it does the job Dan.