Thanks. I need all the help I can get. I’m working on my own build of a driverless cob setup that should blow the junk I’ve made so far away.
2 Likes
What kind of cobs and how do you plan to power them?
120vac powered driverless 50 watt each. That light puts out full spectrum and has 25,000 lux at 18 inches. It’s about 10,000 at 3 feet. Draws 120w for both lights. I’m building a 600 watt light (5 lights) out of luan and plywood to see what kind of box I’ll need for proper cooling. The heatsink gets to 200° without cooling. I can get it down to 120° with 4" computer fan. I want it down to 90 or less so I might need forced air
So they are 120vac cobs, where do you go about finding them? You’re definitely short of being able to cool those passively. But 120 F isn’t terrible, cooler is better though.
The 600 watt light you plan on building with these cobs, or something different?
I’m building with the 120v cobs.
I get them from China. They’re about $3 apiece. The heat sink is $10 from parts express. The lens/collimator is about $3 from China. I put 2 40mm fans ($1each) on the back of the heatsink but it’s not enough, so I found these little 12v squirrelcage type blowers for $5 a piece. I will have one of them at each heatsink. All cooling will be driven by a computer power supply that I have plenty of. Each light will end up costing about $30, so a 600 watt light will cost me $150 minus the box. The great thing is the cobs are so cheap, I will have plenty of spares when they burn out. Some guy on YouTube did a test on the 220v version and they’re built suprisingly well.
2 Likes
Do you have any technical data on them?
I read somewhere that they do have a driver, but it’s installed on the board. Any idea if that’s accurate?
Sounds like a fairly cheap way to get into some cobs anyway. I’d be curios as to how they perform compared to their name brand counterparts. And replacing them definitely sounds cheap enough, as long as they don’t burn your house down. I’m not saying the will happen if one fails, but it definitely does happen. That’s one of the main reasons the more expensive drivers are so popular, the short circuit and overcurrent protection. Also another reason most will wire their cobs in series.
Those could be just as safe, but without the data you really don’t know. Not I chance I will take, nor be likely to recommend to others. Not without knowing exactly how they are configured anyway.
Also, a larger heatsink could possibly do as well or better than going with a bigger fan.
You got my attention on that… Maybe you can put some more information about this…
Oh I agree 100% about recommending them to anyone else. I’m building these lights for me. I don’t recommend anyone messing around with these voltages unless you are well trained. I am. I use a ton of caution with high voltage. Fortunately fire won’t be a problem. I was a fire alarm tech for the last 16 years so I have a good handle on that. I was a tech helping design the most sophisticated spy equipment the military had before that. The only thing I can find out as far as the design is a guy on YouTube toying with them. He has a drawing of the light. It has current limiting to prevent overheating. If you do a search titled driverless cob LEDs, you’ll find what you’re looking for.
2 Likes
The heatsink being larger definitely helps. I picked the ones in my photo because they are tapped for cobs, and have holes drilled for mounting. I have some twice that size and you could feasibly go with no cooling. They’re about 130° with the larger heatsink. That’s too hot for me.
1 Like
Sounds like you have a pretty good handle on what’s important. Hopefully they do well for you!
The guy on YouTube that plays around with these LEDs is bigclive. Also he’s on Pantheon. You might check him out if you want to know more about these “Smart IC” driverless cobs. Apparently someone is already selling lights using this technology.
1 Like
I find that on aliexpress… 3-5$ 1 piece… I think I will purchase 4 of them and put them on every wall(side lights)!
You have something to measure them? I don’t think them are 50 real watts
I measured them at the wall. 2 are 120watts. Should be pretty close. They are driven hard by the on board drivers on the 50 watt version. They all have 74 LEDs so I think the wattage is close to correct. The 20 watt version is not driven near as hard. You might want to buy a few of those and play with them. You can get lens/collimator for about $3. It really concentrates the light.
1 Like
I want to try this one… But I don’t know if is fitting inside the glass. And how is better to install the fan, to blow in the heatsink Or the other way around
1 Like
The lens isn’t necessary if it doesn’t fit. They actually block a portion of the light. They typically give less overall light to create a more intense beam directly underneath the cob. @M4ur
And you want to blow the air down onto the heatsink. So in a way to bring cooler air into the channels of the heatsink, forcing the warm air away.
2 Likes
Thx @dbrn32… I will buy 2-4 of that cheap cob and give them a try… I also looking for the blue ones… The red ones is for flowering stage right?
1 Like
Yep! They red can be used all the way through, but too much red in veg will cause a lot of stretch.
I’m planning to use them for side lights, I have a meizhi 450w for 2x2x5 grow box but I think I need more,