Any COB builders around? Best guides?

Budley Doright

Budley Doright

Well-Known Member
iHearAll said:
nice whats the actual power draw?

nvm i looked. its not posted
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Is it not 250 watts? And there is where I get confused lol. If it's a 1000w then how is it only 250w lol. I did notice that it used epistar COB's, that's a good thing right? Anywho I'll keep reading and trying to learn, I'm a high voltage guy, nothing to work on a 575v rooftop but not so much DC micro amp stuff lol
 
iHearAll

iHearAll

Well-Known Member
Budley Doright said:
Is it not 250 watts? And there is where I get confused lol. If it's a 1000w then how is it only 250w lol. I did notice that it used epistar COB's, that's a good thing right? Anywho I'll keep reading and trying to learn, I'm a high voltage guy, nothing to work on a 575v rooftop but not so much DC micro amp stuff lol
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high voltage AC is fundamentally the same as power DC minus the reactances of capacitors and inductors. except that everything being powered is coming off an AC line so reactances are actually your best friend if you wanted to hand make a ballast for 5$ versus 20$. ha

but yea the LEDS are 200w epistars. i use full spectrum 100w epistars that i got on a crazy cheep sale. theyre nice and cool but are arguably lower in efficiency compared to the LEDs you might find on mouser.com

@Michiganmeds1982
yes you can. you need to determine if your supply voltage is 12 or 24vdc. then find some light you like that are some max voltage higher than that. ideally you want something around 26-30v max power capable for a 24v supply

for a 12v supply you can find 12v bulbs but be careful because the power supply is likely to put out 12.6v which will cause a huge increasing change in current draw versus 12 on the spot. anyway, get yourself a meter if you dont have one and measure the voltage across the supply output go from there.



PM me if you need electrical engineering advice.



Here's a little graph of how semiconductors react to power changes. Notice that you have voltage on the X axis and current on the Y axis. As the voltage increase slightly in a particular voltage away from zero it really starts to eat up more current. This increase in current draw drastically changes the power consumption. It gets radiated out as heat and causes light failures really quick. This is anywhere past the max current suggested by the manufacturer. I fast blo fuse my lights at the particular current ceilings but i'ev never had a blo out .....even in a thunderstorm...phew

IFD2527_FIG1.gif
 
Budley Doright

Budley Doright

Well-Known Member
God I hope we haven't jacked this thread but it is about building them so ..... :). Ok let's see if I understand this, if you under drive the lights re voltage then your going to get better effencies but less intensity, and over driving will burn em out. Also when in series would the last light not be dimmer than the first? Do you have to worry about the current load in the driver and stay over the amount of load for all the lights? I'm so confused lol.
 
iHearAll

iHearAll

Well-Known Member
Budley Doright said:
God I hope we haven't jacked this thread but it is about building them so ..... :). Ok let's see if I understand this, if you under drive the lights re voltage then your going to get better effencies but less intensity, and over driving will burn em out. Also when in series would the last light not be dimmer than the first? Do you have to worry about the current load in the driver and stay over the amount of load for all the lights? I'm so confused lol.
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ok so all of the lights in series will be the same current and whatever voltage it takes each light seperately to achieve this current is the voltage you use to find your series voltage. if you needed 30v to get 3a then 4 LEDs in series would make 120v at 3a. in parallel it'd be 30v 12a.


likewise in another parallel setup, like what would happen using a 12v or 24v supply, you would add the currents up. if the LEDs were 12v using 1a then 4 of these in parallel would be 12v using 4a. and in series you wouldnt br able to use the pc power supply anymore because 4 in series would need 48v and 1a.

since power consumption is voltage times current, the total power consumption is the same
it's safer to underdrive LEDs and they'll last a good many years if correctly heatsinked.


you want your LEDs to be stronger than the supply. if your supply is a regulated 24v supply and you out a 23v LED on it, it will power the LED really really brightly and burn it out in minutes. so if you have a 24v supply and 24v LEDs you need to still be careful because this is the max rating that youd be going by. so look for good solid datasheets the have actually recommended supply voltages. then use the "typical voltage".
 
Michiganmeds1982

Michiganmeds1982

Well-Known Member
iHearAll said:
ok so all of the lights in series will be the same current and whatever voltage it takes each light seperately to achieve this current is the voltage you use to find your series voltage. if you needed 30v to get 3a then 4 LEDs in series would make 120v at 3a. in parallel it'd be 30v 12a.


likewise in another parallel setup, like what would happen using a 12v or 24v supply, you would add the currents up. if the LEDs were 12v using 1a then 4 of these in parallel would be 12v using 4a. and in series you wouldnt br able to use the pc power supply anymore because 4 in series would need 48v and 1a.

since power consumption is voltage times current, the total power consumption is the same
it's safer to underdrive LEDs and they'll last a good many years if correctly heatsinked.


you want your LEDs to be stronger than the supply. if your supply is a regulated 24v supply and you out a 23v LED on it, it will power the LED really really brightly and burn it out in minutes. so if you have a 24v supply and 24v LEDs you need to still be careful because this is the max rating that youd be going by. so look for good solid datasheets the have actually recommended supply voltages. then use the "typical voltage".
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I get what your saying, So my thought is the pc supply is prob 200 + watts, the voltage I'm not sure of but 200 watt supply for say 300 watts of led will make them last longer because they only get 66% of the rated watt?
 
GreenLeafKief

GreenLeafKief

Member
cobkits.com, so far, has quoted me a price of plug-and-play 4x1825 citizen COB kit at $540. I need to frame it so maybe $560 total. I can run them very efficiently at 100watts each, so above results would be great, but I hope to eventually get them to 125+ watts each with proper cooling in my own house next year.


Do you guys think I should go for 6 or even 8 cobs, run at lower wattage?

2 drivers, 3, 4?
 
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PerroVerde

PerroVerde

Well-Known Member
Budley Doright said:
Pretty sure that can be done with 400 watts of any light but the advantage would be heat? I'm asking btw as I'm just starting to read up on LED in general.
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I know I am doing better with 400 watts of COB's then I was with 600 watts of hps. I haven't read or seen in the time I've grown many people pulling a pound or better with 400 watts of any light. My last run was a little over 20 ounces. This run will be less because I had a secound cultivar that didn't pan out and was cut early but I'm hopping for close to a pound. I get the same amount of light with 400 watts of COB's that I did with my 600 hps just 200 watts less heat and waste... :)
IMAG1422.jpg
 
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GreenLeafKief

GreenLeafKief

Member
Budley Doright said:
Pretty sure that can be done with 400 watts of any light but the advantage would be heat? I'm asking btw as I'm just starting to read up on LED in general.
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17 oz. from a 400w? of low-maintenance, non-hydro, non-FIM/Topped plants? Dude thats 1.19 GPW, I dont think a 400w HPS can do that very easily ; + heat benefits ; + will last as long as any 2-3 HPS bulbs. let me know if you have seen different, but i think it would have to be with a lot more effort than the above photo.

Thats why I am going LED, for long-term benefits. I am curious now/reading up on using 10000 or 12000 to finish plants, UV lights, and far red 560 or 700nm lights.

edit: @PerroVerde i had your back lmao

Appreciate your thoughts guys
 
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PerroVerde

PerroVerde

Well-Known Member
Thanks @GreenLeafKief , it's appreciated... :)

I have had 365nm UVA mid day (full last days of flower), 660nm deep red wake up and 730nm far red lights out and to sleep...
 
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iHearAll

iHearAll

Well-Known Member
GreenLeafKief said:
monos ?? type of led? wattage?
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monochromatic. i dont remember the manufacturer. i bought the LEDs a year ago and didnt get around to building the panel until 2-3 months ago.. they're various red spectrums and various blue spectrums each rated for "100w". (which was pretty false advertising cuz the reds were 22v @ 3a.. thats 66w...) so there's 6 red and 4 blues. i can turn on only red or only blue or both. the panel runs somewhere around 420w :bigjoint:. but its only reds and blues because because because
 
Budley Doright

Budley Doright

Well-Known Member
PerroVerde said:
I know I am doing better with 400 watts of COB's then I was with 600 watts of hps. I haven't read or seen in the time I've grown many people pulling a pound or better with 400 watts of any light. My last run was a little over 20 ounces. This run will be less because I had a secound cultivar that didn't pan out and was cut early but I'm hopping for close to a pound. I get the same amount of light with 400 watts of COB's that I did with my 600 hps just 200 watts less heat and waste... :)
View attachment 3784173
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Yes that is good, sorry it just didn't look like there was a pound in that pic. The best I've done under a 400 was 420g of White Russian and that was the only one I ran using a 400.
 
Budley Doright

Budley Doright

Well-Known Member
iHearAll said:
these are built onto recycled wood and flooring. (and a magnum 357 panel) they're each ballasted with bubblegum and shoelaces. theyre each ballasted where a single AC capacitor is being used as a power resistor that emit no waste into heat. then rectified the AC into DC so the LEDs can be run on 90-100v DC in series. the big light is 6 red in series and 3 blue + 1 white in series. i got the LEDs a few years ago and got around to building it recently. so its balasted on 5$ worth of parts and works like a charm. View attachment 3783365 View attachment 3783366 View attachment 3783367 View attachment 3783368 View attachment 3783380
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Got a wiring diagram, those I can follow lol. I see three capacitors, a start, and two run's but that's the only things I know :).
 
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