Spot on…a19 with the covers removed
1 Like
There’s people doing some pretty cool things with them. Hopefully you hit the target, seems reasonable if all else goes well.
You said Hong Kong, is that an alibaba purchase? Just wondering if you’d mind sharing parts list and cost, so everyone would have an idea? Also, what color temp did you go with?
Parts list for diy 800+ watts led fixture and lights.
- Six 16pack a19 bulbs $26 each (ebay)
- 100 plastic ceiling lamps $1.40 each (hm depot)
- 20pcs of 4’ deck railings $3 each (hm dpt)
- 100’ 14 gage wire $15 (hm dpt)
- Liquid electric tape $10 (hm dpt)
- Drywall screws (no cost)
That’s about it, so roughly $400 or less I’m sure some of this stuff could be found even cheaper I just didn’t have the patients…lol
3 Likes
120 Volts AC full wave rectified gives you 170 Volts DC peak. This charges the big capacitor so every 120th of a second,It has 170 volts across it. Then the incoming voltage drops down on a half sine wave to zero, before starting the next cycle. The COBs draw current from that capacitor continuously, so the voltage drops until the next half wave cycle charges it up again. The voltage is a funny line that follows a half wave sine function up to 170 and then drops on a fairly straight line down until it hits the increasing voltage of the next cycle. The slope of that descending voltage line is a product of the size of the capacitor: Essentially ripple. About 23% now. With a bigger capacitor, it will be lower.
It looks like this:
5 Likes
I’m picking it up for the most part. So are similar behaving circuits the cause of flicker in some of the less expensive drivers? I’ve never really seen them flicker first hand, just read about.
I’m weighing this here cost and performance vs the mean wells, so I hope you don’t mind all the questions. From what I’m gathering, this is behaving as a constant current or at least designed as such? And the 143 watts at the wall is running how many of what version (voltage) of the vero’s?
2 of the Vero 5000K high voltage parts: BXRC-50C10K1-C-74
Cheap drivers would probably not use very big expensive capacitors, so they would have more 120 Hz ripple. You can see that if you look at fluorescent tubes with your peripheral vision. I guess you could see it with LEDs, too. Fortunately, VERO COBs are specified to run okay with lots of ripple as long as you don’t exceed the maximum voltage and current values.
They’re like 70 volts nominal right?
Hlg 185 wouldn’t be exactly the best fit at 1050ma but it sounds like they would fit 2, and be something like 90-93% efficient for like $46.
Yes, that’s about what I found looking on their site and some dealers. It is not a bad price for running two COBs when you consider the cost of my parts and labor.
By the way, these are the wrong Vero parts for this approach! I just needed something fast and I will come up with a better design later, and the VERO 29 you pick will not matter. That will be a full switching power supply design. This is a passive design that just throws away the extra voltage. The best possible efficiency with these parts is a bit under 80%. With the other voltage options you could run a string of 4 of the low voltage parts and get 89% efficiency or 3 of the mid-voltage parts and get 89.5% efficiency. Mean Well drivers are 90-95% efficient because they don’t throw away the excess.
One thing that makes the passive design possible is that while the usual voltage is 120 VAC, it can surge as high as 132 VAC. If you were trying to run the COBs at full power, they would not be able to take the surge without some active current limiting. But I’m only trying to run them at less than half power for efficiency, so they can easily stand a 132 volt surge. They will just get a bit brighter for a few seconds.
1 Like
What’s the actual draw from the wall? I’m considering building a fixture like that for veg. I have a setup like it in an old kitchen hood with 8 X 12watt bulbs for seed starter and it really works good.
Are you getting any pulse or ripple?
Are these the 12 watt 12 volt bulbs you can get at Home Depot? Because you could just wire 10 of those in series and plug it right into the 120 VAC with no 12 power supply and no loss. You could also add a simple dimmer if you wanted.
My design is drawing 143 watts right now and has over 20% ripple. But it uses 2 $28 COBs! I’m still working on it.
2 Likes
Really interested in seeing how this turns out brother.
For sure, that’s pretty much where I’d be with it.
200 watt driver for $50, probably not worth the hassle for average guy. But there could be substantial savings at higher fixture output. Let’s say you’re saving $15 per pair of cobs, if you’re building 800 watt light that would be like $60. Especially if you configured to run closer to 90% efficient.
No, they’re 110vAC bulbs that you put into a lamp.
I bought a bunch of cheap rubber sockets at the local electrical supply house and bought the 12watt LED lights on Amazon in 10 packs for about $1 each and took the diffuser off. I found the hood at the dump. The fan on it even works. The whole thing only draws 110 watts. The CFls I had in it before I had the LED idea (actually stole from YouTuber) drew about 200 watts. Watts is heat so I had to come up with something besides CFls. Sorry about the long reply, but my original post about this had terrible pictures. I know better now.
1 Like
On a side note @dbrn32 if you buy drivers in bulk you can save alot at power sager. Just a fyi and I don’t know if I am allowed to post that type of info?
1 Like
You can post about it I think. Just not post link.
Almost everyone will give volume discount.
The bulbs are standard a19 bulbs 8.5w/60w led equivalent…have not attached amp meter…so yeah
2 Likes
I’m experimenting to see what kind of circuit works well and is simple enough to be cheap. I have the input side figured out, now I’m just trying output designs. I actually found a very simple one that a website claimed is widely used for high power LEDs. I think I may be able to make it more efficient than a simple passive circuit and it does constant current output independent of input voltage variations. I’ll post it here when I get the parts and get it working. It should let the input pulse with no ripple to the output. Makes it a lot easier to measure performance.
I wish my camera was working. It has some kind of battery problem so it only works for a few seconds at a time. I have a very nice fixture built with two heatsinks and a little driver board in between them, Wish I could post a picture!
1 Like
My totally DIY COB driver is running two 5000K Vero29 COBs, of the C type (highest voltage). The COBs run at 133.7 volts with 1.226 Amps from the driver. According to my watt meter, it is 83.3% efficient. I have some big honking heatsinks I got as surplus on eBay, which are necessary because I have a big bipolar transistor soaking up the 16.7% (and turning it into heat). The heatsink with the transistor is definitely hotter.
Considering all the labor of building one, it’s probably easier just to buy Mean Well drivers, but it was fun and cheap.
I’m trying to reveg some plants now that I have harvested all six strains. They like the light, but a couple of them were too far gone to make it.
2 Likes
Sweet! Sounds like you got the efficiency tuned well enough to justify it anyway. You have any pics of the setup?
1 Like