I thought I would share my current lighting project. It is an array of 10 80w SMDs that are water cooled to keep heat out of the 24x48" tent, as the radiator is external. I've been making the lights as individual air cooled units before this. The plants respond very well to them. The layout should make the lighting more even in the tent. The 80w lights will be under-driven to 50w, so this should draw 500w. 8 lights have 4:1 ratio of red to blue spectrum and 2 (center) lights are full spectrum. The tent is designed for 6 plants, which is my legal limit. I will update as I complete the assembly. Let me know if you have questions.
I finished the plumbing and wiring today. Everything is looking good, but my burn-in test showed that I will need a bit more cooling before I turn on all of the lights. I also need an auto shutoff of some sort if the water flow stops. Here is a close-up of one of the nodes: I've been planning this thing for a long time and spent around $500, so I hope it works out.
Very interesting build my friend. I've built a couple of light now and will be watching this thread...
Two of the COBS are 80w cool white (6500k). Eight of them are 80w grow lights with 4:1 ratio 660nm to 445nm diodes. They are each individually driven with 50w drivers. The heat sinks are 40mm CPU cooling blocks. All of these parts come from ebay. I've used the COBs before as individual hanging lights using air CPU coolers. The plants love them and they put out a lot of light. I don't drive them to 80w because they only put out 20% more light and produce a lot more heat when I do.
That's sick, I was on some other forums learning about the dyi and I couldn't find any e doing water cooling on them. One day I love to try some dyi, hod do you plan to supply water for it, what's the set up looking like for that? Also what driver?
Thanks brian, yeah they don't do well driven 100% right now i'm trying out a 30w & driving at 20w. being in not such great shape i cant do a whole space at once but want to ad a couple or few 80 100w maybe even vero's (plugs make it easy for me) around other lights for now. I have a bunch of psu's from 90w to 500 + wouldnt mind looking at 12v side lighting options ... and this could also power the fans. What size wire is good for everything ... even up to like the 72v cobs ? Thanks and Thanks for the write up cool project reminds me of the liquid pc craze lol
I haven't seen anyone doing water cooled either. With that many lights, I wanted to keep the heat out of the tent. Below is one of the drivers. I connect one end to a PC power cord with the end cut off and connectors crimped on. The output is connected to 18ga wire that leading to the COB. Below are pics of the water setup. It is basically a container with a submersible aquarium pump running through a radiator. After testing, I found that I will need a bigger radiator and more fans to keep it cool. The cheap pump works fine.
Use a transmission cooler there pretty cheap, decent size and cool very very well use can get them with barbs threaded opening and various sizes and tube sizes But a basic chrap one should do great.
Water temp stabilized at 94F with only half of the lights on. That is warmer than I want. I need more cooling. I'm waiting on some more parts from China to improve it. I also have a Raspberry Pi 3 that I plan to use for an emergency shutoff in case of overheating. It will also be used for keeping the hydro bins full, taking photos, montioring temp/humidity/PH and uploading it all to the cloud. That will be another project in itself.
Don't know if you need this much heat dissipation but here's a cheap heat exchanger. 8" Water to Air Heat Exchangers
Thanks, speyfly. I actually ended up buying this one. They looked better than the PC cooling options for the money.
I have one that I use in my drying box to control that intake air temp and thought it may work for your project. From your pictures it looks like the water flow is daisy-chained with the input side being the coldest water and the return having warmer water form temp buildup. Have you thought about a water distribution center (10 outlets ) so you can have the same water temp to each cob? Just tinkering with your design and looking at the possibilities, I like it!!!
That is a good point. Honestly, I didn't plan the flow. I will have a thermal sensor on the hottest one and shut everything off if it gets out of range. The daisy-chain design works well with this. If I see a lot of temp buildup I will replan the water flow with a distributor.
I finally got all of the stuff I need. I'm going to do final assembly tonight. BTW, the quality of the heat exchanger you recommended is great. I had to do some soldering to make it fit my tubing. There is very little resistance if I blow through it. I wish I had bought this first.
Very happy to hear that you're happy with the heat exchanger and yes they are pretty good quality. That unit should take care of any heat no matter how many COB's you're running plus any other cooling that you may need in the future..
Indeed. The temp is stable at about 89F. This is now a lot of effective light, little power, and won't produce much heat in the tent. I can't wait to hang it up. If anyone is curious about parts or process or making this, let me know.
I'd like to see a write up/tutorial on it. never hurts to have more DIY projects to help the grower on a budget!