8 or 16 COBs LED enough for 8x4 tent?

NoTilFarmer

New Member
Hey 420Magazine Users,

I'm seeking for an answer from some experienced mates with COB LED Growlights. The thing is I'm going to grow in a 8 x 4 Tent (240cm X 120cm) and I'm not quite sure if my selfmade COB LED setup would be enough for this perticular space.
Are 8 "CXB3070" at 1400 mA enough or should I invest another 100-200€ for 16 "CXB3070" at 700 mA?
If I go with 8 COBs I'm going to get the "Mean well HLG-185H-C1400A" Driver with 1400mA and if 16 COBs then the "Mean Well HLG-185H-C700A" Driver with 700 mA.
By the way the COB Lights (CXB3070) are from Cree Inc..
I have never growed under a LED Lighting before but the selfmade COB lights appealed to me as I saw beatiful results on Youtube growers such as HerbinFarmer or Growmau5.

Thank you for your time,

NoTilFarmer
 
One of our colleagues posted that 1400 mA was the ideal current for LED lighting with Chip on board arrays. I can't remember if the argument was based on lifetime of the LEDs, or efficiency.
 
You need 160,000 lumens for a pretty decent grow, so 16 COBs would do it.

Am i reading that right, this driver "Mean Well HLG-185H-C700A" has 429 volts output?
 
One of our colleagues posted that 1400 mA was the ideal current for LED lighting with Chip on board arrays. I can't remember if the argument was based on lifetime of the LEDs, or efficiency.

Think I Growmau saying 1400 was the sweet spot, best all around efficiency with greater number of photons because of greater number of light sources using the same amount of watts, but driven lighter, that would also extend the life of the Chip. So, its both Leafy Greens i would say.

EDIT: actually i had it backwards.

700ma is the most efficient, because lower current, more photons because more sources, but same watts from wall.
 
You need 160,000 lumens for a pretty decent grow, so 16 COBs would do it.

Am i reading that right, this driver "Mean Well HLG-185H-C700A" has 429 volts output?

even if it was, it would only run 12 cobs, but at 12 watts each, lol..
 
edit my logic again.

I guess, per growmau, you can run 8 cobs on that, its 286 volts, but using 25watts each.

Heck, i might even do that, lol.
 
ebay, and there are cheap route too.

Cree, vero , citizen, generic are the options. i guess in that order. you can get a cheap set-up, on the generic side, for around $17.00 per light. That includes light, fan, heatsink, driver, .. That driver is only 200watts, so like i said, it will underpower your cobs at 24 watts, wont get most benefit, i think anyways.



The awesome thing is, you can go cheap, you can go expensive, but to get things rolling and learn from them, its cheaper the the BS blurple lights.
 
You need 160,000 lumens for a pretty decent grow, so 16 COBs would do it.

Am i reading that right, this driver "Mean Well HLG-185H-C700A" has 429 volts output?

Damn, I think 160 000 lumens is going to double my budget. When buying 16 CXB3070 I don't think I have enough lumen, because regarding to the product characteristics one COB incorporates 8750 lumen tested at 1900 mA with 128 lm/W. Or is the COB attaining the same lumen anyways even with lowered current (mA)? You mentioned that 25W per COB will underpower them. How much watts per COB is optimal for the most lumen output? Is "the more watts the better" applying in this situation?
By the way the Driver unfortunately has 286 volts output, which will force me into buying two Drivers and assembling 8 COBs to each one (286V / 36 V = 8).
I actually don't want to spend more than 500 €/$ on my LED set up but on the contrary I need to get a well decent run.

Thanks for your fast replies,

NoTilFarmer
 
Damn, I think 160 000 lumens is going to double my budget. When buying 16 CXB3070 I don't think I have enough lumen, because regarding to the product characteristics one COB incorporates 8750 lumen tested at 1900 mA with 128 lm/W. Or is the COB attaining the same lumen anyways even with lowered current (mA)? You mentioned that 25W per COB will underpower them. How much watts per COB is optimal for the most lumen output? Is "the more watts the better" applying in this situation?
By the way the Driver unfortunately has 286 volts output, which will force me into buying two Drivers and assembling 8 COBs to each one (286V / 36 V = 8).
I actually don't want to spend more than 500 €/$ on my LED set up but on the contrary I need to get a well decent run.

Thanks for your fast replies,

NoTilFarmer

yeah needs 2 for 16. but they are only like $55 each,

Most cobs, 50w to 150 watts. You can get alot from them, but with more ma, more heat transferred to losing watts generated.
 
I spent the last 2 hours calculating different builds. I came to the conclusion to grow in a 5x5 Box (150x150cm) instead of the 8x4 (240x120cm), because I think there is no point in having much space available but no light to fill it up.
The solution consists of:
- 2 X HLG185-C1400A (143V; 200W; 1400mA)
- 8 X CXB3590 with 5000K (36V; 145 lm/w)

This will leave me with stable 400 wall watts and 50 watt per COB. The Price all together (without assembly kit and heatsink) is 392,74 €.
Im open for any improvements.
 
if you plan on vegging only, 500K is fine, but you want 3000k for flower, but 3000k will also veg, and 4000k will do both. OR you can use 5000k for veg, and change the lights when you flip to 12/12. Easy task.

Also, Id get a flower initiator from RapidLED. they are $30 but well worth it i hear. If you dont know what it does, it kick starts the sleep cycle when you turn the lights off. the plant takes up to 2 hours after you turn the lights out before it starts its night process. So, this light given to the plant for 15minutes at the end of the day, cuts that 2 hour process off. it takes like 15 minutes now.

Far Red Initiator Puck
if you get it, use growmau5 for the discount code

I have no affiliation what so ever,

I think this piece is a must in all grow rooms. If you want, you can build your own also. Youll be building your own lights anyways, you could simply add these into the plan, or buy it, plug and play.

Good luck either way you go for your build, but put up pics when your done ..
 
2320 lumens psft bro. 5,000 is the benchmark for above average, usually, you want no less then 3000 psft. So, some use watts per sqrft, and youd be looking at 16watts persft. Rule of thumb for LEDs is 50wattspsft.

what about 5x3?

Youd be at around 3866 lumens pst, and 26watt spsft
 
or just use half the tent, at 4x4, and put some panda film ( White PVC plastic) to create a closed 4x4 area to still get reflection.

You could grow some shit in there for sure with 8 cobs. 2 plants, veg for 55 days, top top top, scrogg, tuck 2 weeks into flower, and boom, 1.5 lbs.
 
and, if you really want to turn it over fast, get some 45-50 finish day seeds. BOG seeds has some fast finishers. cut tent in half, use half for flower, half for veg. ;)every 50 days youll be harvesting, 50 days veg, 50 days flower, badda bing.
 
Thanks for the information, then I will simply change to a 3500K/4000K then to have better results. I heard of those lights and I think if my budget allows me to I will definetely purchase those. I just have to search through the web, because ordering from most american websites charge about 50 bucks for shipping.
I still have two questions remaining. Is it better/possible to connect multiple drivers together so I just end up with one plug?
As I'm not living in america, I have a socket of 220V. Are those 220V going to be a problem when plugging one Driver in the Socket, as my socket (220V) contains double amount of volts than the american socket (with about 110V).

Thank you,

NoTilFarmer
 
and, if you really want to turn it over fast, get some 45-50 finish day seeds. BOG seeds has some fast finishers. cut tent in half, use half for flower, half for veg. ;)every 50 days youll be harvesting, 50 days veg, 50 days flower, badda bing.

I'm going to have a second tent (4x4) anyways , because of some mothertrees, so I'll have my own clones but with a weak 125W HPS lamp.
I'm going to think about your suggestion with making a Veg/Bloom space.
 
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