High End COBs vs $2 COBs...

muleface

Well-Known Member
you forgot to mention the bulbs are safer, they are ul/ce listed with normal sockets for normal people. you can build out a whole 120-130 lm/W array at $0.30 USD/W, and make it as small or as big as you want. every time i go onto the big box stores these are better and cheaper than the last time i was there

last year they were $7 for 100 lm/W (with globe on)
now they are $5 for 110-115 lm/W

and if they break (ive never seen a bad one) they are warranteed and a local return in many cases

while these are generally cost-driven by federal efficiency standards, at some point there is no point for the diode manufacturers to turn out low-flux chips when its probably cheaper to turn out high flux chips and use one less per board. ill bet they dont bin that much lower than the top shelf mid powers out there
is there a real thought that drivers will be a thing of the past? If you could build a LED bulb that got me to 25-35 watts, id be on board
 

Observe & Report

Well-Known Member
you forgot to mention the bulbs are safer, they are ul/ce listed with normal sockets for normal people. you can build out a whole 120-130 lm/W array at $0.30 USD/W, and make it as small or as big as you want. every time i go onto the big box stores these are better and cheaper than the last time i was there

last year they were $7 for 100 lm/W (with globe on)
now they are $5 for 110-115 lm/W

and if they break (ive never seen a bad one) they are warranteed and a local return in many cases

while these are generally cost-driven by federal efficiency standards, at some point there is no point for the diode manufacturers to turn out low-flux chips when its probably cheaper to turn out high flux chips and use one less per board. ill bet they dont bin that much lower than the top shelf mid powers out there
All that and you still have idiots defending their use of screw-in CFLs and refer to anyone who points it out as a "hater."
 

CobKits

Well-Known Member
is there a real thought that drivers will be a thing of the past?
never. the IC drivers will never compete with a meanwell.

you can build an amp or a DA converter out of a $10 chip. a $1000 component could use that same chip but the way they control, buffer, and correct the signals in and out of the chip is what youre paying for. good drivers pay for themselves pretty quick with high efficiency, durability, and longevity
 

nfhiggs

Well-Known Member
The problem with 100-110 lm/w is that it means they're quite clearly outperformed by LED bulbs.

I can get philips 13W bulbs for under 5 euros here, they're 115 lm/w with the globe on. 130+ with the globe removed.
No need to get a heatsink, no need to get a driver.
Just a ceiling socket and a piece of wood to screw it in.

Also the system cost of a China cob isn't even that much cheaper because unless you insist on buying Cree the COBs are a minor part of the whole price.
LOL - Not really true at all. They ARE a major part of the cost - even at $12-$15 per cob. You're still assuming the use of premium Mean Well drivers at $0.25-$0.30 per watt, and $20-30 dollar passive pin heatsinks. While I'm using $3 CPU heatsinks, and budget power supplies that cost $0.07 per watt. You guys dunno how to "Ghetto DIY" this shit... LOL.

We are easily in the same efficiency ballpark as those Philips 13W bulbs. When you figure in the number of sockets you have to kludge together, those LED bulbs are not as nearly cheap as they first seem on a per watt basis. I can make 300W of COB light using a $25 power supply, six $2 COB's ($12), six CPU heat sinks at $3 each ($18) a $6 wallwart 12V supply to run the fans and $20 worth of wire and doodads. Roughly 80 bucks total. 300W of those 13W LED bulbs are going to run ~$120 just for the 24 bulbs you need - not to mention all the sockets and splitters. As for that "UL listing" and Warranty - that's out the window as soon as you rip the globe off the bulb to get that 120-130 L/W.

Don't get me wrong here- I think the LED bulbs are a good affordable option as well, but they are not really the cheapest...

There's more than one way to skin a cat, and more than one configuration for building COB's.
 
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nfhiggs

Well-Known Member
you forgot to mention the bulbs are safer, they are ul/ce listed with normal sockets for normal people. you can build out a whole 120-130 lm/W array at $0.30 USD/W, and make it as small or as big as you want. every time i go onto the big box stores these are better and cheaper than the last time i was there

last year they were $7 for 100 lm/W (with globe on)
now they are $5 for 110-115 lm/W

and if they break (ive never seen a bad one) they are warranteed and a local return in many cases

while these are generally cost-driven by federal efficiency standards, at some point there is no point for the diode manufacturers to turn out low-flux chips when its probably cheaper to turn out high flux chips and use one less per board. ill bet they dont bin that much lower than the top shelf mid powers out there
At $5 per 13W bulb, you're already at $0.38 per watt without the sockets...
 

CobKits

Well-Known Member
those are 15W bulbs but sure its still well under 0.50/W

if you wanted to be cheap you could reflow your own boards with HQ mid-power diodes and learn how to build your own power supplies

i guess the big advantage of the A19 bulbs is
-cheap as dirt
-efficient
-super relaible
-available locally
-meet performance standards vs several of the people in this thread alone who have gotten burned by unscrupulous sellers. the A19's energy efficiency is mandated to be on the box. the imports may or may not even be 100 lm/W for all you know
 

nfhiggs

Well-Known Member
those are 15W bulbs but sure its still well under 0.50/W
My build is about half that at roughly $0.28 per watt.
if you wanted to be cheap you could reflow your own boards with HQ mid-power diodes and learn how to build your own power supplies
Don't think I haven't thought about trying that. I've hand soldered my fair share of surface mount components... And I actually did build a 12V regulated supply "from scratch" using Radio Shack components - many, many years ago. I used it for testing low power 12V electronics. Fun times...

i guess the big advantage of the A19 bulbs is
-cheap as dirt
-efficient
-super relaible
-available locally
-meet performance standards vs several of the people in this thread alone who have gotten burned by unscrupulous sellers. the A19's energy efficiency is mandated to be on the box. the imports may or may not even be 100 lm/W for all you know
I'll concede that last, though the seller I buy from seems to be OK so far.

Got a question for ya - are you familiar with the Samsung Acuity light strips? I've got ten of the 56 diode strips but I am not sure of their power rating. All I know is they run at 94 volts, but I'm not sure how much current they will handle I'm thinking of running them at 300-350 mA.
 

CobKits

Well-Known Member
are you sure they are 94V? if the board says 94V-0 on it thats usually a UL flammability code
 

nfhiggs

Well-Known Member
are you sure they are 94V? if the board says 94V-0 on it thats usually a UL flammability code
Ahh... You are correct... They are a much lower voltage. I just put 34V on one and it lit up bright as fuck! I was assuming (from the numbering on them) they were two 28 diode series strings, which would generally be around 90-ish volts for full power.

Gotta break out the 24V supply and start playing with them..

Edit - these here: http://www.ebay.com/itm/262916650691
 
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nfhiggs

Well-Known Member
limit the current and you can map out Vf vs I pretty easily
Looks to be 24V. I get right at 1 amp with 24V and 2 amps at 26.3

I think I am going to order some 44" long .601" heat sink strips from Heatsink USA, and see if I can run these at 1.5 amps. 5 of them will only run me 16 bucks plus shipping. That's should just about max out my 24V power supply. The strips are 22" x 0.75" and I'm going to make a 44" x 18" grid with them. Definitely gonna pick up another set of these.
 
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frica

Well-Known Member
LOL - Not really true at all. They ARE a major part of the cost - even at $12-$15 per cob. You're still assuming the use of premium Mean Well drivers at $0.25-$0.30 per watt, and $20-30 dollar passive pin heatsinks. While I'm using $3 CPU heatsinks, and budget power supplies that cost $0.07 per watt. You guys dunno how to "Ghetto DIY" this shit... LOL.

We are easily in the same efficiency ballpark as those Philips 13W bulbs. When you figure in the number of sockets you have to kludge together, those LED bulbs are not as nearly cheap as they first seem on a per watt basis. I can make 300W of COB light using a $25 power supply, six $2 COB's ($12), six CPU heat sinks at $3 each ($18) a $6 wallwart 12V supply to run the fans and $20 worth of wire and doodads. Roughly 80 bucks total. 300W of those 13W LED bulbs are going to run ~$120 just for the 24 bulbs you need - not to mention all the sockets and splitters. As for that "UL listing" and Warranty - that's out the window as soon as you rip the globe off the bulb to get that 120-130 L/W.

Don't get me wrong here- I think the LED bulbs are a good affordable option as well, but they are not really the cheapest...

There's more than one way to skin a cat, and more than one configuration for building COB's.
The moment you start using those budget power supplies you throw out even more efficiency.

The light bulbs are clearly a lot more efficient.

China cobs that advertise around 95 lm/w then an 85% efficient psu or so is just a systen efficiency of 80 lm/w. That's rather shit.

Also it's easy to find led bulb bargains on ebay. Not hard to find ge brightstik deals under 0.2$/watt

Besides that the bulbs are more efficient so you need less wattage any way. And are cheaper to run.

Those cool white china cobs are measured at 97 lm/w on their ebay page.
Warm white cobs have lower lm/watt ratings.

You're just paying a premium on your electricity bill with those cobs.
 
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muleface

Well-Known Member
here is what i learned from my first question that started this thread (or what i think i learned)

feel free to double check my math....suppose your goal is to get 212,500 lux (yeah, i know, we don't use lux)



Cheap cob = 100l/w
Cheap driver = 85% eff
total = 85l/w
50 cobs @ 50 watts
2.5 kw/h
total lux = 212,500
12 hours @ .10 kwh = $3.00 a day
$90 a month
$1,080 a year

Vero 29 gen 7 3500k cob = 155l/w
meanwell driver = 96% eff
total = 149l/w
30 cobs @ 47.5 watts
1.425 kw/h
total lux = 212,325
power = .10 kw/h
14.25 cents an hour
12 hours @ .10 kwh = $1.71 a day
$51.3 a month
$615.6 a year

$464.4 savings

Things to consider:

- I only like to use meanwell drivers, not because they are cool, not because they are efficient, but because when i go to bed at night running meanwells, i don't think, Jeez, I hope my drivers don't catch fire and burn down my house.

- the up front cost will be more with Vero cobs
50 cheap cobs x $3 = 150
30 vero cobs x $22 = 660
$510 cost difference

- driver costs will also be more upfront, but meanwells will last forever
 
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nfhiggs

Well-Known Member
"I don't think, Jeez, I hope my drivers don't catch fire and burn down my house."

Gee... Hyperbole much? It really kind of irritates me when people toss out this kind of FUD....
 

CobKits

Well-Known Member
considering a lot of cheap drivers are open frame thats not a stretch at all. i tripped a gfi with sloppy watering last night
 

muleface

Well-Known Member
"I don't think, Jeez, I hope my drivers don't catch fire and burn down my house."

Gee... Hyperbole much? It really kind of irritates me when people toss out this kind of FUD....
So I had to google what FUD means, you kids and your catchy phrases. I am not a seller, have any relationship to sellers and don't own stock in meanwell, so there is nothing in it for me if they sell drivers or not. Suggesting FUD here would indicate I have some vested interest in this, like I have an axe to grind with some off brand seller of Chinese drivers and am attempting to steer the members of this forum from them or my sister is sales rep for meanwell. None of which is true.

https://en.wikipedia.org/wiki/Fear,_uncertainty_and_doubt

Also my statement was not exaggerated as it was literally my thought when I was deciding which driver to buy. So by definition not hyperbole. Once could argue that the only evidence i have that off brand open frame drivers are unsafe or a fire hazard are from a phone call from a buddy of mine that shocked himself with this style of driver. But i am unsure if it was from not properly grounding his driver, design defect, quality control issue with that specific driver or he's an idiot. With that said, I have never had a grounding problem with meanwell drivers nor have ever shocked myself.

hy·per·bo·le
hīˈpərbəlē/
noun
noun: hyperbole; plural noun: hyperboles
  1. exaggerated statements or claims not meant to be taken literally.

When im pushing 250 volts and 400 watts though something, I like to know the company that makes it has a legal concern in the item being safe, when I don't see a company name on something and have no way of identifying the manufacture , it makes me nervous. Meanwell makes a sealed metal case, if something goes south, it will be contained. If an open frame driver decides to burn out, it isn't contained. This isn't some philosophical concept, its a practical one. Going with a the lowest bidder on a high voltage high wattage devices, tends not to be best. Meanwell makes a very efficient driver at a reasonable price.

If I wanted to save money, I would go with bargain basement cobs before i would ever consider using bargain drivers.

Perhaps a better way to frame your disagreement with my statement might be something like, "I have used value priced drivers and have never had a safety issue. I find the lower price point a good way to expand my growing operation without sinking much needed capital into infrastructure."
 
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