• Here is a link to the full explanation: https://rollitup.org/t/welcome-back-did-you-try-turning-it-off-and-on-again.1104810/

cheap chinese COB - 2017

caretak3r

caretak3r

Well-Known Member
ordered a couple of these:
https://www.aliexpress.com/item/2017-New-Arrival-COB-IC-LED-Lamp-Integrated-SMD-Chip-High-Lumen-Real-10W-20W-30W/32799082392.html

Note - the 100W chip and the 70W chip are exactly the same -- no sense in ordering 100W version.

I was hoping these would compare favorably to a vero 18 (I have a gen6) when run @ 10W or less and so far, it appears to do pretty well in my simple lux meter tests. I tested the chinese cob against a vero18 4000K 80CRI (gen6) at 270ma. the Chinese cob was drawing 27.5V and the Vero 27.0V. the both scored really similar #s on my cheap lux meter at equal distances. I don't have any good ways to do precise measurements so maybe I'll ship one over to @CobKits to throw in the sphere just for fun :) If it was to hold up over time, it's a decent value at $2.19
HTB18vXKQXXXXXczXVXXq6xXFXXXt.jpg
 
BuddyColas

BuddyColas

Well-Known Member
caretak3r said:
I just wanted to take a look at the latest offerings of dirt cheap no-name cobs. I'll do more testing and post in case it's helpful to anyone else.
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What kind of shipping did you use...and how long did it take? Are you planning on making a fixture, or more for education?
 
caretak3r

caretak3r

Well-Known Member
BuddyColas said:
What kind of shipping did you use...and how long did it take? Are you planning on making a fixture, or more for education?
Click to expand...
12 days from order to delivery, bought 2 chips, paid for epacket delivery (which was $3). No promises on longevity on these compared trusted brand (bridgelux/cree/luminus/samsung/etc). I just like trying stuff out, and I saw that on most of @CobKits testing, the big brand cobs were converging when driven < 20W. I figured I'd order the latest cheap cobs with the most diodes and see how they faired < 20W. If they did well enough, i theorized that one could make a panel on the cheap. In short, a crappy 100W cob might be a decent 10W cob.
 
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caretak3r

caretak3r

Well-Known Member
one note, it was quite difficult to get any solder to stick to the pads on my first sample... I'll read up on how to better prep the pads for the 2nd. I have a tube of flux if that's all it needs...
 
PicklesRus

PicklesRus

Well-Known Member
Yes very interested to see if we can build cheap panels with these. Maybe they would mount to an aluminum baking sheet and not need any extra heatsinking lol

"Ultra cheap grow light"
 
Randomblame

Randomblame

Well-Known Member
caretak3r said:
one note, it was quite difficult to get any solder to stick to the pads on my first sample... I'll read up on how to better prep the pads for the 2nd. I have a tube of flux if that's all it needs...
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Hey careta3r
Clean it with some isop. alcohol or so and maybe grind it a bit. Some solder flux is always helpful. Give some tin to the solder pads and tin the wire a bit before you put them together.
 
caretak3r

caretak3r

Well-Known Member
Randomblame said:
Hey careta3r
Clean it with some isop. alcohol or so and maybe grind it a bit. Some solder flux is always helpful. Give some tin to the solder pads and tin the wire a bit before you put them together.
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thanks, I did some light sanding and that helped quite a bit. I ordered 10 more, so I'll add the ISO alcohol step to the list when I process the rest.
 
caretak3r

caretak3r

Well-Known Member
DaveInCave said:
What do you think about those?
https://www.aliexpress.com/item/LED-COB-Bulb-Lamp-Light-Beads-30W-50W-70W-100W-150W-220V-Input-IP65-Smart-IC/32738716696.html

Will the 150W be any good?

I posted here, but maybe it would have been smarter to post in this sub forum instead:
http://rollitup.org/t/150w-chinese-cob-led.939202/
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I would stay away from the boards with driver built in... You have no control over what amount of power you are going to run through them so you can't run them soft.
 
DaveInCave

DaveInCave

Well-Known Member
Few questions:
1. What do you suppose will happen if I use a variac with those for example?
2. Lets say I don't run them soft, will there still be any advantage to running them over HPS?
3. Can you recommend any low cost Chinese cobs to make a light that will be 'good enough'?
 
Randomblame

Randomblame

Well-Known Member
DaveInCave said:
Few questions:
1. What do you suppose will happen if I use a variac with those for example?
2. Lets say I don't run them soft, will there still be any advantage to running them over HPS?
3. Can you recommend any low cost Chinese cobs to make a light that will be 'good enough'?
Click to expand...
Hi Dave!

If you drive them low you'll maybe get 120-130lm/w with a lot good will.

If you drive them at their rated current or use 220V COB's it's more like 80-100lm/w.

No advantage from using this over HPS except perhaps better spectrum and heat control.

Lower currents means better efficiency, better efficiency means more light for less energy. A typical HPS ist rated to 130-150lm/w you need to beat that to get better results, watt per watt of course.
 
caretak3r

caretak3r

Well-Known Member
Randomblame said:
Hi Dave!

If you drive them low you'll maybe get 120-130lm/w with a lot good will.

If you drive them at their rated current or use 220V COB's it's more like 80-100lm/w.

No advantage from using this over HPS except perhaps better spectrum and heat control.

Lower currents means better efficiency, better efficiency means more light for less energy. A typical HPS ist rated to 130-150lm/w you need to beat that to get better results, watt per watt of course.
Click to expand...
Please pay attention to the above post, @Randomblame is 100% on the money.

Think of this thread as experimental.... if you need to replace HPS and want to use COBs, please consider the offerings from Citizen, Luminus (cobkits.com provides these) or Bridgelux..... those are tried and true and of good quality (they will last). This thread is about considering the possibility of building a panel of the newer cheap no names.... I wouldn't suggest anyone go out and buy them for a grow light yet. Lights are my hobby right now, so this is just me sampling some stuff that not everyone has played with.
 
DaveInCave

DaveInCave

Well-Known Member
Randomblame said:
No advantage from using this over HPS except perhaps better spectrum and heat control.
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I would say these are very important advantages, since we are not producing light for lighting's sake, we are trying to produce lights for plants to use.
If the spectrum is better, wouldn't that compensate for lower efficiency?

caretak3r said:
Think of this thread as experimental
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I'm a huge fan of such projects and experiments :)
I'm definitely not going to base my commercial grow operations on Chinese cobs :)
Like you, I also like to try new things, maybe I will give it a go and report back if I find something interesting.

It would be nice to able to build a light cheaply, that will also be efficient and produce good yields.
I think if I can make a 800W light for $100, and get 1<g/w yield I will consider it a win, even if it's slightly less efficient than HPS, and brand names LEDs.
 
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