The DIY COB Addiction

Wait I just reread what you said, what's the difference with the constant voltage and constant current drivers, I was wanting to use 4 vero 29 50v and use 2 hlg- 185-1400b drivers, is that not gonna work? Trying to get 400w out of 4 cob like that one they sell on timber. But yours is beautiful and right up the ally of what I want
 
You would need the 185-2100 to get 100w per chip(105w).. I dont know forsure if it will do 2 though... I will check.. That is running them pretty hard though, your efficiency will go way down. You will also need some big heatsinks. Even the 1400 will run them at 70w a piece.. The problem with the 50&72v chips is they dont fit well with constant current drivers. Constant current means the current stays the same.. Thats what the 1400 or 2100 is.. Milli amps.. Or ma..
Volts x current = watts..
50volts x 1.4 amps = 70w
50 x 2.1 = 105w

50&72v chips run better on constant voltage drivers. I think there is a hlg400-48b.. The voltage is locked but the current changes as u add more chips.. More chips@lower watts = higher efficiency..
Higher efficiency = more light than heat per watt...
What size of space are u trying to light?
 
Damn that was exactly what I was confused about, just a 39"×39"×70" tent. Trying to figure out if diy cob will be better for that space the a CMH light
 
jimmyclone said:
You would need the 185-2100 to get 100w per chip(105w).. I dont know forsure if it will do 2 though... I will check.. That is running them pretty hard though, your efficiency will go way down. You will also need some big heatsinks. Even the 1400 will run them at 70w a piece.. The problem with the 50&72v chips is they dont fit well with constant current drivers. Constant current means the current stays the same.. Thats what the 1400 or 2100 is.. Milli amps.. Or ma..
Volts x current = watts..
50volts x 1.4 amps = 70w
50 x 2.1 = 105w

50&72v chips run better on constant voltage drivers. I think there is a hlg400-48b.. The voltage is locked but the current changes as u add more chips.. More chips@lower watts = higher efficiency..
Higher efficiency = more light than heat per watt...
What size of space are u trying to light?
Click to expand...
Why would 50/72v work better on constant voltage than constant current ? would'nt you be able to put more chips with high voltage on the same driver ?

36v at 1.4a = 50.4w
72v at 1.4a = 100w

To get the same wattage output you would need less drivers ? As i'm not electrician or electricity engineer or nothing near of that i'm simply a diy guy for many other things... is it that the driver with fixed milliamps are only available in 36v 1400 ma or would we be able to get drivers that goes up to 72v and cut a little the cost ?

Sorry for these many question i'm trying to gather as much informations as i can to build my own and i really appreciate your help
 
jimmyclone said:
So people that dont know, quality cobs are the most amazing grow lights available for the price, Hands down. Efficiency, spectrum, control, customization. I wanted to share my build and time with these little gems.

Lets look at the spectrums here first.
The McCree curve is what we are trying to achieve here
420-magazine-mobile1703534152.jpg

You can see that cob lighting fills much more of the gap than hid. Now there are many more options for cob spectrums than what is shown here. Vero now actually has a 1750k chip.. Then we have 70,80,90 cri options.. I did say customization..

Here is an efficiency chart comparing some of the most common quality cobs.
420-magazine-mobile2121054722.jpg


So lets go through some of my build..

16x vero29 se 3500k
4x meanwell hlg240-1750 b drivers

Built into 2 36"*36" panels to go in my 8*8 tent. I only use a 4*8ish space inside.

420-magazine-mobile2103927207.jpg
420-magazine-mobile1138686567.jpg
420-magazine-mobile1712432323.jpg
420-magazine-mobile1819260477.jpg
420-magazine-mobile170868526.jpg
420-magazine-mobile683495562.jpg
420-magazine-mobile1884484698.jpg
420-magazine-mobile1774586969.jpg
420-magazine-mobile184879911.jpg


So i went from 1000w hps at around 20" away to 330w over 8 cobs at 30-36" away on my 2 final girls from last run and in 12 hrs they were showing severe signs of light stress. I had more tacos then the local burrito shop.. So down to 250w i went and they were praying like they never had b4.. Extremely powerful little things.

Now these really aren't that hard to build.. Much , much cheaper than high end prefab leds, and you can easily get a much higher ppfd for your grow space.. And if you dont want to tackle the build yourself you can order a timber kit in the US (pretty expensive though) or there is a guy on here from canada that builds and sells quality cob panels. Also check out autocobs, great guy with a quality product as well. If your going to try to build one, Rapidled.com is a great place to start, they have everything you need to get going besides aluminium angle..

Please, please, please, people, think twice about buying blurple crap..
White light is the way forward, blurple was a bad mistake...

Thank you
White Light Warrior
Click to expand...

Thanks for the post man.

So u had a 1000 hps there right?

And ur saying this is for sure stronger (also looks bigger and expensive)

And ur saying its 330 watts or so, but does more??

Have you done full grow with it yet?

How much $$$

How much time???

Thanks

You way worth it or.....
 
Forgot to add
Or if the driver has a maximum of example 100v
It would be better to putt 2 50v chips than 2 36c chips in serie as voltage add up in series and amp adds up in parallel (am i making error here?)

Sorry if i'm making few error in explanation and question my english is not really on point so if you need something to be clearer ask and i'll do my best!
 
cnile said:
Thanks for the post man.

So u had a 1000 hps there right?

And ur saying this is for sure stronger (also looks bigger and expensive)

And ur saying its 330 watts or so, but does more??

Have you done full grow with it yet?

How much $$$

How much time???

Thanks

You way worth it or.....
Click to expand...

The new COB setups are beginning to average 2gpw. They are so bright and efficient that growers are now looking for light recipes rather than more light.

Cheers,
/Obi
 
I see well over $1000 there, one hell of a setup for sure but also very expensive, I just wanna spend like 4 maybe 500 tops. Not trying to be the man or anything I just wanna grow 2 plants as good as I can
 
Constant current drivers have a forward voltage. This is the maximum voltage the driver can output.. As u add chips in series you add the voltage because the current is constant.. So lets say a driver has a forward voltage of 250volts
You can run
3*72v chips
5*50v chips
7*36v chips
On constant voltage each chip will divide the available amperage..
So say theres 5 amps available on the driver.
You could run
2 chips at 2500ma(dont do this)
5 chips at 1000ma
10 chips at 500ma
Or anything in-between.
Hope this helps
 
I have a journal on another site for these.. Not alot of strech on these girls. Definite learning curve with these things. Had the light way to low for the first bit, way too strong.. Temps were too low... Thats right, too low.. Had to add a heater.. 21-23c was perfect for my old hps, but these things dont throw much heat at all.. 2 weeks. Of slow growth.. Then i raised the light to about 3-3.5 feet above the canopy@ 350w, temps up to 24-26c and away they go...
 
jimmyclone said:
Constant current drivers have a forward voltage. This is the maximum voltage the driver can output.. As u add chips in series you add the voltage because the current is constant.. So lets say a driver has a forward voltage of 250volts
You can run
3*72v chips
5*50v chips
7*36v chips
On constant voltage each chip will divide the available amperage..
So say theres 5 amps available on the driver.
You could run
2 chips at 2500ma(dont do this)
5 chips at 1000ma
10 chips at 500ma
Or anything in-between.
Hope this helps
Click to expand...
Yes it does help !!
But as i can see you are using constant current and variable voltage drivers, is there any reason for that ?
Growingmaster said:
Looking sweet in here,good job;)
Click to expand...
 

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