Bars vs Boards

wietefras

wietefras

Well-Known Member
@end_of_the_tunnel, What would be the market for that though? I'm all for spreading the light, but at some point it doesn't give any practical benefit anymore. If you double the number of strips from 1 per 2x2 (or 2x4) to 2 strips you see a huge improvement in uniformity. Double it again to 4 and the additional benefit is already a lot smaller. You'd need to hang the light at 3" to still really notice improvements. Who in practice would like to go that low?

Probably the biggest volumes are for professional growers. For instance the Gavita 1700e design allows it to be at 6" over a 4'x4 and 10" over a 5'x5', but they aim at a larger growers market showing a configuration for 15 lights marketing hanging them at 24", because that's more practical in really large grows. While also explaining it could be used in multi layer grows, but then you can get a bespoke light calculation from them.
 
Lockedin

Lockedin

Well-Known Member
So, we're aiming for even propagation

But we all know that the edges will not receive the same light as the center - there are simply more oblique angles available for illumination in the center of any area then at the edges.

Would it not make sense then, to setup lighting in more of a domed configuration?
Highest light in the center, edges and corners lower (no idea by how much, just thinking out loud)
Higher performance reflectors around the perimeter of the canopy (mylar?) would help redirect more energy back towards the center, somewhat mitigating the hot spot in the middle.
 
E

end_of_the_tunnel

Well-Known Member
wietefras said:
@end_of_the_tunnel, What would be the market for that though? I'm all for spreading the light, but at some point it doesn't give any practical benefit anymore. If you double the number of strips from 1 per 2x2 (or 2x4) to 2 strips you see a huge improvement in uniformity. Double it again to 4 and the additional benefit is already a lot smaller. You'd need to hang the light at 3" to still really notice improvements. Who in practice would like to go that low?

Probably the biggest volumes are for professional growers. For instance the Gavita 1700e design allows it to be at 6" over a 4'x4 and 10" over a 5'x5', but they aim at a larger growers market showing a configuration for 15 lights marketing hanging them at 24", because that's more practical in really large grows. While also explaining it could be used in multi layer grows, but then you can get a bespoke light calculation from them.
Click to expand...
Sorry wietefras, you asking me about my reply to Humple on a solution for strip builders? Or an earlier post?
 
E

end_of_the_tunnel

Well-Known Member
Lockedin said:
So, we're aiming for even propagation

But we all know that the edges will not receive the same light as the center - there are simply more oblique angles available for illumination in the center of any area then at the edges.

Would it not make sense then, to setup lighting in more of a domed configuration?
Highest light in the center, edges and corners lower (no idea by how much, just thinking out loud)
Higher performance reflectors around the perimeter of the canopy (mylar?) would help redirect more energy back towards the center, somewhat mitigating the hot spot in the middle.
Click to expand...
I have looked at par maps posted from many sources. Think that simplicity rules. Not saying you could not try a create a configuration as you suggest, just thats its nature of the beast to have hot zones no matter how you try to apply the light in a given area. Most products out there have some warmer zones/spots. Does not neccessarily mean they are bad. I guess as humans we like uniformity, and maybe get caught up in the fine details.
 
Randomblame

Randomblame

Well-Known Member
Haha! What that's for a crazy debate? I just realize how much I missed that, lol!

As long as you spread the diodes evenly you can get the same uniformity with both, strips and boards.
I can buy lots of single row 1ft strips and mount them on a heatsink in the exact same layout like we have on boards and voilá, even the EIS files would almost look the same.
And on the other hand I can use 4 or 6 boards, cover the whole ceiling and get almost the same uniformity I would get from 16 or 20pcs 4ft. strips evenly spaced across a 4x 4'.
They both use the same type of LEDs(mid power diodes) what the heck makes one believe it makes a difference if they're mounted on boards or on strips? Its still the same midpower diode and if you distribute them evenly you can create best possible uniformity with both of them.

As with all things there is only one question...!
It depends..? It depends on what you need/want?
Do you have a big room, 3m ceilings and can grow huge plants or do you have a small room in your basement and only 2m to the ceiling?

But I see a much more important difference between these two solutions.
Modern LED strips like EBgen3 no longer need heatsinks when driven at nominal current. Even with 35°C ambient temps you don't see strip temps reaching 80°C. Simply screw them to a frame and that's it. Makes it so easy to use them as side- or intra-canopy light and to combine them with a number of boards under the ceiling.
 
E

end_of_the_tunnel

Well-Known Member
wietefras said:
@end_of_the_tunnel, What would be the market for that though? I'm all for spreading the light, but at some point it doesn't give any practical benefit anymore. If you double the number of strips from 1 per 2x2 (or 2x4) to 2 strips you see a huge improvement in uniformity. Double it again to 4 and the additional benefit is already a lot smaller. You'd need to hang the light at 3" to still really notice improvements. Who in practice would like to go that low?

Probably the biggest volumes are for professional growers. For instance the Gavita 1700e design allows it to be at 6" over a 4'x4 and 10" over a 5'x5', but they aim at a larger growers market showing a configuration for 15 lights marketing hanging them at 24", because that's more practical in really large grows. While also explaining it could be used in multi layer grows, but then you can get a bespoke light calculation from them.
Click to expand...
Ok, I am with you now. Yes, if using more and more strips or boards to cover a given area, you will reach a point where the diminishing returns in uniformity become pointless. Good point.
 
wietefras

wietefras

Well-Known Member
Randomblame said:
you can get the same uniformity with both, strips and boards.
Click to expand...
Agreed, but we are not talking about hypothetical situations though. There are solutions using these and boards end up sold with 4 boards versus 8 strips. That's just how it works out price wise.

Sure you could spend even more on boards to achieve what strips can do, but then it's not really a fair comparison anymore.

To be honest I never understood why simply mounting 4 COBs on a slate didn;t become much more popular than putting a ton of medium sized leds on a board. Hang that thing at 24" or 36" and you really see no difference in 244 medium leds vs 488leds spread over 4 COBs on the same heatsink. With 4 cobs costing only half the price of a single board.
 
Prawn Connery

Prawn Connery

Well-Known Member
Randomblame said:
They both use the same type of LEDs(mid power diodes) what the heck makes one believe it makes a difference if they're mounted on boards or on strips? Its still the same midpower diode and if you distribute them evenly you can create best possible uniformity with both of them.
Click to expand...
Exactly
 
Prawn Connery

Prawn Connery

Well-Known Member
wietefras said:
Agreed, but we are not talking about hypothetical situations though. There are solutions using these and boards end up sold with 4 boards versus 8 strips. That's just how it works out price wise.

Sure you could spend even more on boards to achieve what strips can do, but then it's not really a fair comparison anymore.

To be honest I never understood why simply mounting 4 COBs on a slate didn;t become much more popular than putting a ton of medium sized leds on a board. Hang that thing at 24" or 36" and you really see no difference in 244 medium leds vs 488leds spread over 4 COBs on the same heatsink. With 4 cobs costing only half the price of a single board.
Click to expand...
You do a lot of PAR mapping?

Probably not, otherwise you would know that strips emit light in an elliptical shape.

Here are 4x 48W Cree strips. The reason it is not symetrical? Because no light source is. That is how things are in the real world.
1593712387258.png
 
Lockedin

Lockedin

Well-Known Member
end_of_the_tunnel said:
I have looked at par maps posted from many sources. Think that simplicity rules. Not saying you could not try a create a configuration as you suggest, just thats its nature of the beast to have hot zones no matter how you try to apply the light in a given area. Most products out there have some warmer zones/spots. Does not neccessarily mean they are bad. I guess as humans we like uniformity, and maybe get caught up in the fine details.
Click to expand...
Simplicity Rules - Occam's Razor is one of my favorites - the simplest right answer is the correct one (paraphrased) :D

In a few posts above, multiple qbs are mentioned.......please understand that the next couple sentences are heavily influenced by Legend OG and throw Occam and his razor out in favor of a beard.

Theoretical, assuming a square footprint:
1 large, square qb in center
Strips (or smaller qbs) concentric around and a point or two lower; and another point or two lower on the corners.

A LOT of rigging and wiring, and probably not too efficient.
 
wietefras

wietefras

Well-Known Member
Prawn Connery said:
You do a lot of PAR mapping?
Click to expand...
Yes. Yes I do. I wrote my own software to calculate them. Amazingly I am able to create perfectly symmetrical maps from symmetrical models.

Once you understand the matter you don't need to draw all these individual par maps though. Simply dividing the PPF by the surface area minus the wall losess gives you an average PPFD. Making sure the lights are spread out in the best geometry ensures correct uniformity. You can then draw a map, but why bother?

It's actually better to draw a par map as a vertical slice. Then you can much better see what the best height is for a light. Can you do that?
 
Prawn Connery

Prawn Connery

Well-Known Member
Amazingly, all you do is talk.

While I have been posting PAR maps, you have been showing us . . .

Where are all these programs you talk of? Until you have something, you have nothing. This is boring me now.
 
1

1212ham

Well-Known Member
end_of_the_tunnel said:
Maybe that opens up an potential avenue for some enterprising individual to come up with a cheap sheetmetal heatsink and busbar combination? Thing is, choice of strip is pretty wide, but people could come up with barebone configurations for use. A person with a cnc router could drill screw holes to customer/strip spec, and supply low resistance busbar to suit.
Click to expand...
I've thought about using the frame as a bus bar. Obviously for low voltage only.
 
welight

welight

Well-Known Member
dialux does actually allow you to create multiple planes, so within a single project,you can model 12,18,24, 36 inches etc, so you can see the impact of inverse law relative to canopy obstruction importing 3D plant models, you can also model light on walls, on plants, pretty much anywhere in the room, to date we have barely scratched the surface of what a program like Dialux can bring to just these type of arguments.
I have dogs in all fights, so can you fill a room with wall to wall light, yes you can with either strip, panel or cob, does it make sense, cost says no, and the math does not support it, Light multiplies to the centre and divides to the edges, so the game is massage light position to take advantage of the known properties
wall.jpgverticalroom copy.jpg
 
wietefras

wietefras

Well-Known Member
Prawn Connery said:
I have been posting PAR maps . .
Click to expand...
You are seriously the only one who needs a par map to understand that this:
Code: 
|     |     |     |     |     |     |     |
|     |     |     |     |     |     |     |
|     |     |     |     |     |     |     |
|     |     |     |     |     |     |     |
|     |     |     |     |     |     |     |
|     |     |     |     |     |     |     |
|     |     |     |     |     |     |     |
|     |     |     |     |     |     |     |

spreads the light better than this:
Code: 
           |  |  |  |  |  |  |  |
           |  |  |  |  |  |  |  |
           |  |  |  |  |  |  |  |
           |  |  |  |  |  |  |  |
           |  |  |  |  |  |  |  |
           |  |  |  |  |  |  |  |
           |  |  |  |  |  |  |  |
           |  |  |  |  |  |  |  |
Look at those glorious ASCII par maps! Boom! In yer face! Mic drop!

ps How is something this obvious even up for discussion? Come on man.
 
Randomblame

Randomblame

Well-Known Member
wietefras said:
Agreed, but we are not talking about hypothetical situations though. There are solutions using these and boards end up sold with 4 boards versus 8 strips. That's just how it works out price wise.

Sure you could spend even more on boards to achieve what strips can do, but then it's not really a fair comparison anymore.

To be honest I never understood why simply mounting 4 COBs on a slate didn;t become much more popular than putting a ton of medium sized leds on a board. Hang that thing at 24" or 36" and you really see no difference in 244 medium leds vs 488leds spread over 4 COBs on the same heatsink. With 4 cobs costing only half the price of a single board.
Click to expand...
Yeah, I remember the tests with 4 and 5 Citi 1212 COB's cobkits has done but none of us would use such a high distance just to get the same uniformity. You know, I myself am a strip lower just because of their unbeatable flexibility. I really like what a few sidelights can do if used additionally.

But I really see no difference when it comes to distribution. One can get chinese QB knock off's pretty cheap even with LM301b or h and they are not realy more expensive. If you buy quantum boards (or any other board from a reputable manufacturers) you not only pay more for your diodes. You pay for support, warranty, customer service, full employee salaries and so on and in most cases its not a big company like Samsung you deal with. So yeah, most boards are more expensive but the prices come down already while Sammy strips became much more expensive within the last two years(+20%). I still think its a wash and mainly depends on the situation.

The funny thing is, I was almost a year "behind swedish curtains" and we're still having the same discussions, lol!
 
diggs99

diggs99

Well-Known Member
Randomblame said:
Yeah, I remember the tests with 4 and 5 Citi 1212 COB's cobkits has done but none of us would use such a high distance just to get the same uniformity. You know, I myself am a strip lower just because of their unbeatable flexibility. I really like what a few sidelights can do if used additionally.

But I really see no difference when it comes to distribution. One can get chinese QB knock off's pretty cheap even with LM301b or h and they are not realy more expensive. If you buy quantum boards (or any other board from a reputable manufacturers) you not only pay more for your diodes. You pay for support, warranty, customer service, full employee salaries and so on and in most cases its not a big company like Samsung you deal with. So yeah, most boards are more expensive but the prices come down already while Sammy strips became much more expensive within the last two years(+20%). I still think its a wash and mainly depends on the situation.

The funny thing is, I was almost a year "behind swedish curtains" and we're still having the same discussions, lol!
Click to expand...
Man its good to see you back, much love <3
 
You must log in or register to reply here.
Top