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Off the shelf retail store screw-in LED and CFL bulb comparisons

F

frica

Member
brown_thumb said:
QUESTION: If the increase in output below the bulbs is only ten percent then might it be better just to leave them on to increase diffusion and sideward dispersion?
Click to expand...

No, because LEDs already have a very wide beam angle.

The diffuser of the LED bulb only adds losses and "throws" light upwards and other directions away from the plant.

Without diffuser all the light goes downwards to the canopy, and it's already radiating with a pretty wide angle.
With diffuser, part of the light is lost inside the bulb and then another part is getting lost because part of the light got redirected away from the canopy.
 
B

brown_thumb

Active member
I understand and if the loss is twenty percent (I'll bet its closer to thirty percent) it makes perfect sense. But if the difference truly is only ten percent then I don't see much gain by removing the globes. Has anyone actually measured the difference? Also, isn't there some benefit to the diffusion? I mean, don't LED's tend to concentrate their light unevenly in spots? The globe-less type I tried did... very much so. The latter remark pertains to the multi-LED types, not the single large LED type.
 
F

frica

Member
brown_thumb said:
I understand and if the loss is twenty percent (I'll bet its closer to thirty percent) it makes perfect sense. But if the difference truly is only ten percent then I don't see much gain by removing the globes. Has anyone actually measured the difference? Also, isn't there some benefit to the diffusion? I mean, don't LED's tend to concentrate their light unevenly in spots? The globe-less type I tried did... very much so. The latter remark pertains to the multi-LED types, not the single large LED type.
Click to expand...

If you want to light a room, it's nice if the light is diffused and not shining in one direction.
It's different with growlights where you want all the light to hit the plant.

10% is likely generous, it's probably closer to 15%.

The only way for the beam angle to be too narrow is if you're getting some reflector halogen replacement with a 30 degree beam angle and placing it an inch from the canopy.

With replacement bulbs you're already getting enough spread because the bulbs are spread out and individually they aren't that bright, even if they hurt your eyes when you look at them.
 
starke

starke

Well-known member
Brown Thumb

Look at blynx's measurements on the first couple of pages of this thread for performance on the LED with and without the globe. There is a difference:

10w 2700k LED with lens
12" 24 lux
6" 110 lux
9" 534 lux

10w 2700k LED with no lens
12" 37 lux
6" 165 lux
9" 707 lux
 
HuffnPufferfish

HuffnPufferfish

Member
not a valid number starke, youll need a ulbrich sphere, ive contracted a company to test it, but their reply was pretty obvious: we dont give a fuck about household bulbs
 
F

frica

Member
HuffnPufferfish said:
not a valid number starke, youll need a ulbrich sphere, ive contracted a company to test it, but their reply was pretty obvious: we dont give a fuck about household bulbs
Click to expand...
For a growlight, it's not like the diffuser is doing anything to help.
You aren't illuminating a room with it, you're just trying to rain photons on the canopy.

You can also compare Blynx his CFL grows with his LED bulb grows.
CFL bulbs are almost perfectly diffused and throw light in every direction.

Ultimately it just meant that he managed the same yield from his LEDs as the CFLs, with 1/3rd the wattage. While the LED bulbs were only a little more efficient. 3 times the yield per watt while only being 20-30% more efficient at most. Simply because LEDs are directional and the CFL is not.
 
B

brown_thumb

Active member
It appears that the 6" and 9" readings are switched. Also, it's a bit confusing that the difference between 'with globe' vs 'without globe' is approximately 33 percent between the two highest distances but only approximately 23 percent between the two lowest distances. Could the anomalous reading be due to uneven lighting?

If the difference is indeed closer to 33 percent (I strongly suspect it is) then it's certainly worth removing the globes... provided the illumination is even enough. Again, the globe-less lights I tried were extremely uneven but it was easy to see because they were the multicolor type. With the meter used, it might be difficult to register the unevenness of lights because the diffusion disc over the sensor is so large.
 
F

frica

Member
brown_thumb said:
It appears that the 6" and 9" readings are switched. Also, it's a bit confusing that the difference between with globe vs without globe is approximately 33 percent under the 12" and (9"?) readings but only approximately 23 percent at (6"?). Could the anomalous reading be due to uneven lighting?
Click to expand...

Different beam angle.

You will see the same thing if you compare a bulb with the globe popped off and a halogen replacement reflector bulb.

The light of the globed one spreads more/faster per distance, the closer it is to the light meter the less the light is spread.
 
B

brown_thumb

Active member
Yeah, that makes sense. At any rate, the difference in those tests was about 33 percent at reasonable distance. So I can see the advantage of globe removal.

Thanks all and sorry for the derail.
 
A

argo430

Member
Veteran
Well the fact i can vary the height of the strips and they are of low foot print I can jack em up to the tent liner if i have to. I am going to let the monster in the tent run instead of tying her down. No complaints so far compared to the two ufo's i pulled out of here. As supplemental lighting I am pleased so far.

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HuffnPufferfish

HuffnPufferfish

Member
frica said:
For a growlight, it's not like the diffuser is doing anything to help.
You aren't illuminating a room with it, you're just trying to rain photons on the canopy.

You can also compare Blynx his CFL grows with his LED bulb grows.
CFL bulbs are almost perfectly diffused and throw light in every direction.

Ultimately it just meant that he managed the same yield from his LEDs as the CFLs, with 1/3rd the wattage. While the LED bulbs were only a little more efficient. 3 times the yield per watt while only being 20-30% more efficient at most. Simply because LEDs are directional and the CFL is not.
Click to expand...
yes but no, leds are always directed, but the bulb is reflecting some to the sides, you CANNOT compare that to a clf that BY DESIGN only puts out 5% down
in some cases the globe will even be benificial, i have a 1 square feet box with 3 leds in it, with globes on, because the overal spread is better with
 
F

frica

Member
HuffnPufferfish said:
yes but no, leds are always directed, but the bulb is reflecting some to the sides, you CANNOT compare that to a clf that BY DESIGN only puts out 5% down
in some cases the globe will even be benificial, i have a 1 square feet box with 3 leds in it, with globes on, because the overal spread is better with
Click to expand...

"Leds are always directed"
Not true
http://static.wixstatic.com/media/f....jpg_srz_968_742_85_22_0.50_1.20_0.00_jpg_srz

"in some cases the globe will even be benificial, i have a 1 square feet box with 3 leds in it, with globes on"
Have you tested the numbers, extremely height constrained, or just making assumptions?

And the CFL was an example of a true example of diffusion.
Of course even with globes they're still somewhat directional, but it serves as an example that the more directional a light is, it's easier to point the most light towards the canopy.
 
blynx

blynx

WALSTIB
Moderator
ICMag Donor
Veteran
brown_thumb said:
It appears that the 6" and 9" readings are switched. Also, it's a bit confusing that the difference between 'with globe' vs 'without globe' is approximately 33 percent between the two highest distances but only approximately 23 percent between the two lowest distances. Could the anomalous reading be due to uneven lighting?

If the difference is indeed closer to 33 percent (I strongly suspect it is) then it's certainly worth removing the globes... provided the illumination is even enough. Again, the globe-less lights I tried were extremely uneven but it was easy to see because they were the multicolor type. With the meter used, it might be difficult to register the unevenness of lights because the diffusion disc over the sensor is so large.
Click to expand...

I fond removing the globe increased the measurements by about 40%.

The 12", 6" an 9" distances are kind of confusing.

12" does refer to the measurements being taken 12" from the light, as does the 6".

The 9" refers to a measurement 9" above the ground, ie the measurement was taken 3" from the light. You can see this in the pictures I posted showing the measurements.
 
B

brown_thumb

Active member
blynx said:
I fond removing the globe increased the measurements by about 40%.

The 12", 6" an 9" distances are kind of confusing.

12" does refer to the measurements being taken 12" from the light, as does the 6".

The 9" refers to a measurement 9" above the ground, ie the measurement was taken 3" from the light. You can see this in the pictures I posted showing the measurements.
Click to expand...

Okay, thank you for the clarification. :)
 
HuffnPufferfish

HuffnPufferfish

Member
frica said:
"Leds are always directed"
Not true
http://static.wixstatic.com/media/f....jpg_srz_968_742_85_22_0.50_1.20_0.00_jpg_srz

"in some cases the globe will even be benificial, i have a 1 square feet box with 3 leds in it, with globes on"
Have you tested the numbers, extremely height constrained, or just making assumptions?

And the CFL was an example of a true example of diffusion.
Of course even with globes they're still somewhat directional, but it serves as an example that the more directional a light is, it's easier to point the most light towards the canopy.
Click to expand...
youre proving my point, they even say its a 360 degrees model..

what do i need to test, i dont get any light to the corners if i remove the plastic, it really is that simple.
 
HuffnPufferfish

HuffnPufferfish

Member
if you make a new kind of bulb where you slam the led material 360 around a metal wire, led is still the same tech

if i make a car with 3 wheels, its still a car.
 
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