LED COB bar project
- Thread starter bmdiyh
- Start date
bmdiyh
Well-Known Member
Thanks man I'll check it out!
robincnn
Well-Known Member
I have been thinking about this for 2-3 days but I don't understand hps vs COB
What is better
1000W HPS DE bare, 40.8% efficient and cheep price
Or
vero COB with running 2.1 a 40% efficient or 2.9 amps 37% efficiency
Clearly hps is more efficient and cheep. Would you still go with Vero at 2.1 amps due to directional light distribution or something ?
Also Vero29 to 3070 difference does not seem worth it to me. 11% more efficient and 24% more $. Not so nice.
Veros 29 to 3590 difference 30% more efficient and 24% more $, this makes sense
The 40.8% efficiency is deceptive, you need to compare par measurements at the top of the canopy over the grow area and account for the extra heat that the hps provides.
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robincnn
Well-Known Member
I think PPFD in Supras post already account for par measurements at the top of the canopy over the grow area
1000W HPS DE bare, 40.8% efficient =
960 PPFD
1184W of heat
-----------------------------------------------------------
Vero29 @[email protected]%
1230 PPFD
1163W of heat
I assume vero 29 @2.1 amp @ 40% , PPFD and heat will look similar to hps
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ppfd does, but the efficiency does not.
SupraSPL
Well-Known Member
Good questions. The efficiency is a good starting point for comparing one COB to another but misleading when comparing LED vs HPS. I would choose the Vero 40% over the HPS 40.8% for several reasons.
-efficiency represents bulb output, so it is before reflector losses but the
-PPFD is after reflector losses, canopy size and takes spectrum into account to some extent
Comparing HPS PPFD vs COB PPFD requires a few considerations. The 1000W DE HPS output is about 40 CRi and the COB is 80 CRi. So the COB output is more evenly spread across all wavelengths while the HPS output is more peaky, saturating certain wavelengths or pushing closer to saturation, especially at high intensities. I am not sure how this would effect photosynthetic efficiency but the 80 CRi makes a lot of sense because the sun is at 100 CRi, very evenly spread.
Second, the HPS PPFD will have less uniformity, bright in the center and dimmer on the edges. The COBs can be spread evenly across the canopy. There is no doubt that this will increase yield and also increases our ability to run at higher overall intensities.
Finally, the HPS emits 825nm infrared output, raising the temp of the buds. This should increase yield but in my experience heat extends the flowering time, encourages dreading/sloppy finish, decrease trichomes, terpenes, cannabinoids and bud density. That is not say say all HPS bud is wack, but it does make it harder to get a truly top shelf finish.
-efficiency represents bulb output, so it is before reflector losses but the
-PPFD is after reflector losses, canopy size and takes spectrum into account to some extent
Comparing HPS PPFD vs COB PPFD requires a few considerations. The 1000W DE HPS output is about 40 CRi and the COB is 80 CRi. So the COB output is more evenly spread across all wavelengths while the HPS output is more peaky, saturating certain wavelengths or pushing closer to saturation, especially at high intensities. I am not sure how this would effect photosynthetic efficiency but the 80 CRi makes a lot of sense because the sun is at 100 CRi, very evenly spread.
Second, the HPS PPFD will have less uniformity, bright in the center and dimmer on the edges. The COBs can be spread evenly across the canopy. There is no doubt that this will increase yield and also increases our ability to run at higher overall intensities.
Finally, the HPS emits 825nm infrared output, raising the temp of the buds. This should increase yield but in my experience heat extends the flowering time, encourages dreading/sloppy finish, decrease trichomes, terpenes, cannabinoids and bud density. That is not say say all HPS bud is wack, but it does make it harder to get a truly top shelf finish.
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SupraSPL
Well-Known Member
As far as cost goes, there are more considerations as well. According to Jair from Gavita, the HPS requires a new bulb and new reflector every year in order to maintain canopy intensity. Not a huge deal but the COB can be wiped with rubbing alcohol anytime to remove any dust/film restore its output and will maintain near 100% output for many years. If you fail to clean the COB not a huge deal but if you fail to change the HPS bulb and reflector, major decrease in PPFD. Of course there are the direct electrical costs of the lamp and even more importantly the electrical cost of environmental control.
A higher efficiency COB will require less heatsink and less driver to get the same job done, partially offsetting the increase in COB cost. It may also allow you to get more intensity in your space and increase overall yield. If so, it pays for itself in days/weeks if you are space, heat or light intensity limited as I was with my 600W HPS setups.
As far as Vero29/307/3590 cost vs efficiency, this depends on the statement above. If running a higher efficiency increases your total yield then (I tend to) justify spending stupid amounts of $ on the COBs. I am planning to squeeze as much light into my tents as 4000W DE HPS, but using only 1500W of COB @ 63.8% efficiency. If I can pull that off and keep temps where I want them, that should increase yield significantly with no sacrifice of quality. If so, the upgrade from 1200W of 48% efficient COBs should pay for itself in 2.5 weeks. That doesnt mean 2.5 weeks of no profit, it means 2.5 weeks before the increase in profit would kick in.
A higher efficiency COB will require less heatsink and less driver to get the same job done, partially offsetting the increase in COB cost. It may also allow you to get more intensity in your space and increase overall yield. If so, it pays for itself in days/weeks if you are space, heat or light intensity limited as I was with my 600W HPS setups.
As far as Vero29/307/3590 cost vs efficiency, this depends on the statement above. If running a higher efficiency increases your total yield then (I tend to) justify spending stupid amounts of $ on the COBs. I am planning to squeeze as much light into my tents as 4000W DE HPS, but using only 1500W of COB @ 63.8% efficiency. If I can pull that off and keep temps where I want them, that should increase yield significantly with no sacrifice of quality. If so, the upgrade from 1200W of 48% efficient COBs should pay for itself in 2.5 weeks. That doesnt mean 2.5 weeks of no profit, it means 2.5 weeks before the increase in profit would kick in.
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dandyrandy
Well-Known Member
Love those cobs.
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littlejacob
Well-Known Member
Bonjour
@SupraSPL what mean DE??? And it is the first time I heard that the reflector have to be change every year!!? I have a friend who have his AAW since 8 years and he always have the same amount of weed (10% more or less) I have mine since 4 years and if i don't change anything in my grow, i make between 400 and 500gr with my 600W(why DE?) hps.
And, yes...i got banned from my french site cause i said on a led company(Bionicled) thread that what you build is better than what they sell (and it is true!!).I don't really care! I feel better here on RIU!!!
Have a great day★
@SupraSPL what mean DE??? And it is the first time I heard that the reflector have to be change every year!!? I have a friend who have his AAW since 8 years and he always have the same amount of weed (10% more or less) I have mine since 4 years and if i don't change anything in my grow, i make between 400 and 500gr with my 600W(why DE?) hps.
And, yes...i got banned from my french site cause i said on a led company(Bionicled) thread that what you build is better than what they sell (and it is true!!).I don't really care! I feel better here on RIU!!!
Have a great day★
salmonetin
Well-Known Member
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SupraSPL
Well-Known Member
According to Jair 60% of the light emitted from an HPS bulb has to reflect off the reflector to reach the target (70% by my calculations). With a perfectly clean reflector, 5% of that light converts into heat on the first bounce. Much of the light has to bounce several times so we end up losing 20% of the light before it exits the reflector.
As a thin film of haze and dust builds up on the bulb and on the reflector surface, a larger percentage will convert to heat on each bounce and more will be scattered/diffused in the wrong direction. We lose another 12% if the HPS is inside a cooled hood and that number increases as dust/film builds up on the glass of the hood as well. It seems like foliar feeding and soil dust would contribute a lot to the film/haze.
Jair explained that the 95% reflectivity cannot be restored by cleaning the reflector and must be replaced to maintain intensity. He suggests to replace it every year and especially if you have a dull reflector to replace it. It rubs me the wrong way because I would feel like I was being wasteful and that is why Gavita uses $35 reflectors. I have used the same aluminum HPS reflectors for several years nonstop. They did not look dull but it is true that my best HPS yields came when the reflectors were newest and yield did continually drop off with time, even when I rotated in new bulbs.
Jair talks about this at 1:07:50 here Adam Dunn show - S1E48 All About Grow Lights
As a thin film of haze and dust builds up on the bulb and on the reflector surface, a larger percentage will convert to heat on each bounce and more will be scattered/diffused in the wrong direction. We lose another 12% if the HPS is inside a cooled hood and that number increases as dust/film builds up on the glass of the hood as well. It seems like foliar feeding and soil dust would contribute a lot to the film/haze.
Jair explained that the 95% reflectivity cannot be restored by cleaning the reflector and must be replaced to maintain intensity. He suggests to replace it every year and especially if you have a dull reflector to replace it. It rubs me the wrong way because I would feel like I was being wasteful and that is why Gavita uses $35 reflectors. I have used the same aluminum HPS reflectors for several years nonstop. They did not look dull but it is true that my best HPS yields came when the reflectors were newest and yield did continually drop off with time, even when I rotated in new bulbs.
Jair talks about this at 1:07:50 here Adam Dunn show - S1E48 All About Grow Lights
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littlejacob
Well-Known Member
salmonetin
Well-Known Member
....maybe this helps...
... thanks for the link Supra...
Saludos
... thanks for the link Supra... Saludos
Stephenj37826
Well-Known Member
Will artic 11 plus cpu cooler work for cxb3590?
testiclees
Well-Known Member
Hey B,
Let me know if it's a distraction posting my bar developments up in here.
I made some progress 1- got the ac power connected to the driver. 2- I got the cob holders mounted using #4 screws and a slightly smaller drill bit, seems tight. 3- I polished up the sink some using 600 and 1200 grit wet paper it stills needs a good rub.
Does this look right???
Let me know if it's a distraction posting my bar developments up in here.
I made some progress 1- got the ac power connected to the driver. 2- I got the cob holders mounted using #4 screws and a slightly smaller drill bit, seems tight. 3- I polished up the sink some using 600 and 1200 grit wet paper it stills needs a good rub.
Does this look right???
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bmdiyh
Well-Known Member
I think it does. Probably depending on how high you run it.
I don't get it. It is not a distraction. I would really appreciate if people share their progress on similar projects here.
dandyrandy
Well-Known Member
Speaking of reflector losses we have heat treat operators that local age or heat treat small areas on very large parts. They use water cooled 5kw lamps. The reflectors must be polished after approx. 50 hours of use or the lamp fixture will be destroyed. All aluminum. And they are sealed, with air or argon "depending" cooling the lamp side. Water cools the reflector!