I'm designing a lighting solution for my Kratky hydroponic plants (basil, tomatoes, peppers) and would welcome your feedback.
I've been reading about the advantages of setting up a LED COB (Circuit on Board) solution with a CC power supply. However I'm planning to setup my hydroponics on an outdoor balcony that can often be humid. For this reason I'm really inclined towards buying regular A19 LED bulbs and hooking them up with light fixtures.
My question is, how much can I work to prolong working life of the LEDs? I see most bulbs estimate their lifetime based on 3 hrs/day operation, but I plan to run lights 16 hour a day. I'm going to a hardware store with thermal camera to compare the hotter and cooler LED brands, but I'm wondering what I can do to prevent what sounds like the most common failure mode of the LED bulbs, which is overheating which causes damage to bulb's power transformer or mains connections. Luckily, average temperatures in my area are temperate, with average ranges from 5 C to 25C throughout the year. I think that air cooling with a fan might help to provide some reasonable cooling.
My tentative solutions are as follows. I'm hoping solutions 1 and 2 are sufficient. What do you think?
- Add a fan (little PC fan or possibly larger fan if required) to force air over bulbs and promote more convective heat transfer.
- Make miniature heat baffles with aluminum foil and attach this to the hottest part of bulbs to help wick more heat away with conduction
- Constructing fixture from sheet metal. Was previously going to drill wood to fit the light sockets. If I use sheet metal I assume that I can help improve heat transfer away from the bulbs. If fan is blowing heat away from bulbs, some heat will reach sheet metal fixture and be wicked away
- Cycle the bulbs. Only run half the bulbs at a time, so the other set can cool. 30 minutes on, 30 minutes off. I'm concerned this may actually age bulbs faster. Thoughts?
- Liquid cooling with a metal tube running near LEDs. Not really a serious consideration. I'm sure this would work to some degree, but I think it would not be worth the effort and condensation on the tube could be a real electrical hazard if it's near bulbs.
Other questions I have:
Can a COB LED and switching power supply be safe for outdoor use? I'm assuming I could possibly find a weatherproof switching DC supply, but how would I go about weather-proofing my solder connections to a COB LED? Or would household LED bulbs be the better solution here?
Fundamentally, what steps can I follow to adequately weatherproof a DIY project where I've been soldering/connecting my own wires? Is electrical tape and heat shrink tubing sufficient?
Thanks for your time and advice!