Next time, threaded rod.
Ya, you’ll figure out better ways to do things as you go. I was actually wondering if you had a way to half those pieces of rectangle tubing? Light may run a couple degrees warmer, but you could cut weight in half and double the amount of material for sinks you have.
I’ll have to think about that. How to do it safely with the tools I have.
A lot of the heat will just run through the aluminum sides up to the top, where it will do some radiation and some convection. But without airflow, the inside is not going to lose much heat. The air will just heat up quickly to the heat sink temperature and then no more heat transfer occurs. Cutting them in half would get rid of that dead space and half the weight, with no difference in heat going out of the heat sink.
You could put some fins in the tubing and run some air through it, but it seems like it is working fine as is.
For sure, just a thought to make life a little easier. Do you know if you have one of those community type fab shops in your area? Where you pay a small fee per month to use their equipment.
Unfortunately no shops around. However, I may relieve the next one with a bunch of vent holes which should help.
Ahh, bummer! It was just a thought. I’m sure you’ll come up with something good anyway.
Maybe you can go to big box store Lowe’s or Home Depot and get you a few metal drill bits and plug in your drills or pick up your cordless drill and have a session or two while drilling holes. That self gratification you would get out of it would be out of this world. Your setup looks very professional right now and if you could find the way to get holes in it or in the next one. I might have to send you a customer or two.
So far I’ve found someone claim that four 1120mm strips at 1050ma measured ppf 478 umols/sec. If we put value into that (hard to do, I know) since it’s a photon flux measurement, we should be able to make a linear conversion. We’ll call it 120 umols per 1120mm strip, or 60 umols per 560mm strip. 10 560mm strips= 600 umols/sec for 10 560mm strips seems high. Higher than I expected. 260 led watts of qb is Ppf of 627. The Samsung diode is about 5% better at that current I think. So ppf for the strips probably a smidge under 600 umols/sec.
What doesn’t come into play, is that the hlg-300 uses zero transfer material to the sink, and is just an aluminum plate as well. So @Myfriendis410 may get a little bump there. Either way, he’s in the neighborhood of a $600 light for $140 worth of leds and drivers. Considering he recycled some aluminum, I bet $200 for complete build? And he should have enough transfer tape, wire, and connectors to build several more.
It is a really efficient build. I wish I could see the intensity and penetration too. @Myfriendis410 did an awesome job.
For sure! They’re capable, just slightly different plan of attack than cobs. You’d run them a lot closer than cobs to get penetration. Which is easier to do since the diode density isn’t as tight. 6 in one, half dozen in the other ya know.
You’re right that the cost all up was around $200 using my own heatsink material. I’ve got enough parts to build a bunch more lights. Incidental stuff like paint, screw eyes, power cord etc.
@Daddy thank you for your kind words. I used to be a hands on mechanical engineer in another life and enjoy working with my hands. The next 2 fixtures will be much better.
In retrospect, some 1/8”x2” 6061 bar stock would do, for anyone wanting to do something similar. I want to say 4’ lengths available locally for around $12 or so. Online metals probably cheaper after shipping. But an extra $30ish or so, still puts someone starting from scratch at or under $1 per watt.
The temperature on the face is 101°F and the top at 97° on the heatsink with the driver. I mounted it on the end one with 3 strips. Next time I’ll move it to one with 2 strips. The center one is at 87° as a comparison.
You’ll be plenty good there!
If you could drill some holes on the bottom as well as the top, not aligned, then you could get a lot of air flowing through the heat sink by convection. They would be even cooler.
My thermal safety switch works: I was feeding the plants and accidentally unplugged the exhaust fan that pulls air through the heat sinks. After just about 10 minutes it shut down the COBs. In troubleshooting, I touched the heat sink and sure enough it was quite hot. Not hot enough to burn me, but it usually runs about 95 F, so I knew right away. My big fan was unplugged. Plugged it back in and about five minutes later it had cooled the heat sinks down enough to turn back on.
Love the “turn back on” behavior. If the fan breaks down while I am asleep, it will keep on turning the lights on for a few minutes until it gets hot, then turn them off until it cools, all night long. Keep them from thinking they should flower.
That’s cool! Could never do that with hid, need to guarantee cool down time before firing bulb again. Granted, you’re not really worried sink temps either.
@Myfriendis410 just realized arrow has full compliment of gen 2 eb strips. Price is higher than everywhere else though, probably the reason they’re still in stock lol. It looked like they discounted quantities of 10 or more. Even after discount looks like about $25 more for 10 of the gen 2.
The increase in the newer strip is about 20 lumens per watt. They have a little lower forward voltage too, so could maybe squeeze an extra strip on that driver. Not sure it’s worth the extra money, but I thought I would pass the info along anyway.