50w LED Spotlight

[MrFancyPlants]

Well the willow leaf is looking way better then before my experiment despite a couple mite induced defoliations in the process. I ended up using some bayer rose and flower systemic to tackle the mites even though it doesn't specifically have mitacide in it. It seems to have done the trick.
Even this too little is way healthier than it was. It was near death and now just has a touch of scorch since it is up near the top of the enclosure.


I moved the thermometer to the top of the cage and realized that one of the lights is getting much hotter then I realized.. into the 90's and I bet a couple spots are getting even hotter based on the scorch. I am toying with the idea of removing the driver from the light in order to distribute the heat better, although I am not sure how much heat the driver itself generates.

On another closely related experiment, my friend and I are going to buy another one of these flood lights and take it apart and install the components into a large decorative hurricane lantern. There is a glass enclosure and one of the doors opens from the side. We are going to put his poor, light deprived coffee plant inside this new contraption. I am pretty excited about the benefits of this new setup. If it looks cool enough it will make it a lot easier to expand my operation matrimonially speaking. And it will be a lot easier to access the plants from the side door. And temperature could be regulated easier...

 

[GrimLore]

Might want to leave the light as is and experiment with air movement - They like the warm and do not want to be cooked but with proper air movement you could prbably do well. We have some "tiny" Ficus in diff varieties here that have done well this way for over 15 years

 

[Kevster]

Might want to leave the light as is and experiment with air movement - They like the warm and do not want to be cooked but with proper air movement you could prbably do well. We have some "tiny" Ficus in diff varieties here that have done well this way for over 15 years

I agree. Every enclosure I've used always had at least one small 4 inch desk fan
( http://compare.ebay.com/like/121014831042?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar) it to keep air moving. It prevents stagnant air from collecting in spots along with hot and cold spots. But doing this will dry out the soil much faster which for me I like and the plants do too. Means I get to fertilize them more and their roots grow faster.

 

[davetree]

You have to have air movement in an indoor garden. Helps the plants exchange gases and keeps away the mites, also prevents lots of different disease.

 

[MrFancyPlants]

Thanks for the input.. I will seriously consider including a fan of some sort in my setup, although maybe just a repurposed cpu fan. Currently, I open it up couple times a day and breath into the aquarium to try and elevate the co2 levels... I know, I might as well play some classical music for them.

I'll be posting a new setup sometime in the next week. Even my wife is excited about this one, which is a big win for me. Stay tuned!

 

[davetree]

What you really need is a fan that blows fresh air in from the outside and vents for the stale air to exit. Or better yet a fan to blow air out as well. Probably the number one mistake indoor gardeners make is not having proper air exchange. It will make a huge difference in the health of your trees. Computer fans are cheap and small and do an excellent job.

 

[Austin]

I have grown fruit in a refrigerator with nothing but sylvania florescent light bulbs with a 6500 spectrum and three fans. I made two planters and set each on it's own rack rather shallow planters in fact to keep them dwarfed they only have about 18 inches of room to grow up in this old free fridge I have. The temps without any exhaust got up to 110 degrees off of four light bulbs in 2 hours, I then put a 6 inch fan in the bottom of the fridge and drilled air intake holes in the side at around ground level (bad idea) and leave the fan plugged in 24/7 keeps temps in the mid 70's low 80's humidity stays roughly between 30-40%. Also I have two four inch fans pointed at the plants from above, no worries I made an air diffuseor so the plants are only being tickled not blown over and have been very successful also for them never having gotten sunlight they look awesome nice dark green color but it does dry out every other day wich all in all is a good thing.

but with your idea I would suggest making a plastic tent with air coming in over the top of the plants and air flowing out the bottom of the tent and use your LED lights for lighting your plants and some Florecent bulbs for heat (and supplemental light is a bonus) as most LED lights function at a 90-120 degree spread instead of the almost 360 degrees given off by other bulbs. you could make or buy yourself a big oven pan and make a humidity tray for the floor of the tent if lack of humidity is an issue.

and if you don't like my idea I would love to see what you did, I read the entire thread and found your experiment promising looking forward to more pictures.

 

[MrFancyPlants]

I haven't been able to set up a fan yet, but it is certainly on my list. I almost had a Rick Moranis little shop moment when I went to check on them this morning. The leaves may look a little funny, but those roots sure like it. There are signs of new growth on each of the trees in the tank.

Here is my next project on hold until I get a heat sink for the led chip. A coworker and I got identical fancy candle holders and we are going to retrofit them with led chips. He doesn't want to risk a fan being noisy and I think that this will be drafty enough that convection will provide all of the airflow that I will need. I am more worried about weather proofing the thin iron construction on the lantern. I was thinking either mineral oil for the easy way out, or maybe silicon and some sort of waterproof paint, but I am open to suggestions.

I was also struggling with the design for the reflector on the led. I finally wrapped my head around the benefits of a lambertian or Matt white reflector, so I may paint the insides of the top glass white, or I may end up repurposing the aluminum reflector in the floodlight since I already have that and it might look better.

 

[MrFancyPlants]

Well the second flood light that I purchased started flickering and went out. I think there is something going on with the power supply as it always ran a little hot. So I had to rearrange some of my subjects. The bejaminas never appeared to like it too much in the enclosure anyways. The original willow leaf is as healthy as it has ever looked. I think the benjaminas may just be a bit too big and haven't liked the scorching temperatures up near the top of the enclosure? (still waiting on the fan).
So I am in a bit of a quandary with the out lamp and in the middle of building out the lantern.

If anyone could offer a bit of electrical engineering advice I would most appreciate it.

I was thinking I would take out the components of my working flood light and install them in the latern. I also have a 100w led driver and 2x50w ledchips that I was planning into the flood lights. I've taken apart one of the lights and the assembly is pretty easy, I just was hoping someone could check my math.

Can I hook the two chips up in parallel to divide the current in half? Should I put some sort of fuse in series with each of the LEDs then? I borrowed a multimeter, but I am a tad apprehensive without the experience.

Driver:
OUTPUT DC:28-40V
DC:3.0A±3%
100W Max

LED Chip(2x):
Forward Voltage 30V to 36V
Forward Current 1.6 A

 

[MrFancyPlants]

Well more bad news. I went ahead with my next experiment using the remaining working flood light innards to install in the lantern. And it worked great... for about 45 min and then turned off I'm pretty sure I didn't use a big enough heat sink for the 50w chip. I didn't include a fan and was hoping the convection would be enough to cool it, but obviously I am out of my league as a LED hobbiest. Pretty frustrated and not sure what my next step is going to be.

I can either try and salvage the floodlighs for my aquarium setup, or get a higher powered heat sink with a fan.

 

[MrFancyPlants]

I'm waiting on the heat sink fan combos for the lamps and I went ahead and hooked up a couple 50w chips on one 100w power supply. The good news is that it is bright and I'm gettin a little more confidant with the multi meter. Although the LEDs are in parallel, I have an additional current regulator circuit in series with each of them. I just double checked w the multi meter and each chip is getting 1.47 amps, a bit below their 1.6 rating. One of them is getting pretty hot so I'll switch out the chassis with one with slightly larger cooling fins. The power supply is getting hot to the touch after a few hours of operation, so I'm going to have some more tinkering to do.

 

[MrFancyPlants]

I have a fan set up now and tinkered around with the floods to try and get maximum cooling out of them so that I am pretty confident letting them run all day. This probably not what you had in mind for the fan setup, but I couldn't help but experiment with a wireless power supply. It doesn't move much air at all, but it is enough to mix the hot air from the top in with the rest of the tank. It brought the temp from the top of the tank down to 84 down from a peak of 95 with the new 100 watt power supply. The original test subject looks quite happy.

 

[GrimLore]

Plants look good and seems you have things under proper control May I ask for a link to that fan assembly? Or perhaps the SKU Number?

 

[MrFancyPlants]

Here is the Amazon link where I got the fan. It is not a powerful fan running off of the LED light instead of solar, but I had to give it a shot for $7. It was better then having to run a separate power supply. I tried putting it right up next to my 24w T5 and there was not enough light to run the fan.. probably too distributed of a light source from the tube.

http://www.amazon.com/gp/offer-listing/B009IJXJ3Y/ref=dp_olp_new?ie=UTF8&condition=new

 

[GrimLore]

Here is the Amazon link where I got the fan. It is not a powerful fan running off of the LED light instead of solar, but I had to give it a shot for $7. It was better then having to run a separate power supply. I tried putting it right up next to my 24w T5 and there was not enough light to run the fan.. probably too distributed of a light source from the tube.

http://www.amazon.com/gp/offer-listing/B009IJXJ3Y/ref=dp_olp_new?ie=UTF8&condition=new

Honest it will be perfect for the application I have in mind and Thank you for the information

 

[MrFancyPlants]

So I ended up getting a new fan and I must say, you guys were sure right about increasing the air flow (not that I doubted you). With the hot spots gone and the roots a bit warmer, even the benjamina is finally showing some new growth. And the original willow leaf is out of control considering how poorly it was doing when I started this experiment.
I replaced the fan because the solar one required too much fiddling to keep in in the right place and running. And it was blocking some of the light for the plants. I like the variable speed on the new fan so I can turn it down until it doesn't make noise. It has a USB power supply and I plugged that into a wall wart adapter. Now if I can only keep from spritzing it when I water with the spray bottle.
I am kind of excited about this benjamina on the left since it was my first air layer. I think it has some potential, and I like the idea of making something out of unsuitable material. I am planning a graft on it this summer. I think once it warms up I am going to plant this in a pond basket in the ground. When I first separated the air layer I gave it is treatment half expecting it to die. I was quite surprised at how far the roots had escaped in just a couple months. I'm not quite sure of the order of operations will be for the graft(before or after I move it outside). Mainly I just need to accumulate enough confidence to make the attempt.

 

[MrFancyPlants]

My original test subject seems to like the enclosure best. It even seems to have put on some girth over the winter despite the mite induced defoliation. Too bad I chopped the top off of it as soon as I got it home a few years ago; the little movement is not natural.
For the record, I've been using dyno grow orchid 7-8-6 every watering this season. I have a bad habit of playing with too many variables, but the lower daily dose seemed more appropriate then the weekly 20-10-10 that I give the temperate varieties when it is warm outside. Every month or so I try to give these tropicals a dunk in a bucket or bowl to give them a flush, and they seem to appreciate it.

 

[MrFancyPlants]

Even the mini elm cuttings I took a few weeks ago appear to be doing well with the led/fan setup. Despite some pest issues the only one that didn't love it in here was the larger benjamina air layer (not pictured) that was scorching near the top. It also had some soil issues going on since it was repotted earlier in a mix containing some recycled soil with too much fine sand and compost. I thought it might be too wet because it was dropping older inner leaves but when I started scraping away the top layers I found a lot of "dusty" areas(not good) where the daily watering a were not penetrating. I got rid if as much as I could and replaced with mostly turface, lava, pumice, sphagnum with a dash of akadama for good luck. It dries out pretty quick but at least I know it is getting wet. Ironically I think the sphagnum wicks the moisture away faster than a chopped bark would. It's like if you leave one of the wet wipes sticking out of the container for a couple days an it siphons off all of the moisture.
The willow leaf has done well but I am not super pleased with the back budding and leaf size. That is probably because I was too eager to chop back after the most recent repotting as I only waited a couple weeks. I am also having issues inducing back budding on the b. (too little), but figure I'll just let it gather some more strength for a while , especially because it looks like I'll be closing on some real access to some real sunlight later this month. It is my first mortgage so i am nervous and quite excited.
Oh and the coffee plant did a decent job of back budding and has smaller leaves than in the real sun. I hope to give it some room to run now that I'll have a real yard.

 

[daz]

Nice work

 

[MrFancyPlants]

Those lights have a bit lower wattage than what I am working with, but if you get enough of them strung up in series it could work quite well. If you use more lower wattage leds, it will probably dissipate the heat quite well.

I like my high intensity source but the 50w in the flood light box seem to approach the limits of solid-state heat dissipation. The reef guys hook the chips up to cpu coolers due to the similar form factor. The heat conductive properties of heat pipes are pretty amazing and will likely be involved in my next high wattage experiment.