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Science Forum Index » Engineering - Lighting Forum » LED light brightness...
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 Posted: Tue Jun 17, 2008 2:35 am |
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Guest
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I'm buying a couple of LED bulbs and LED tubes (direct replacements
for fluorescent tube lights and doesn't require any ballasts)
The supplier told me that their LEDs have CREE or Jinyuan (Taiwan)
chips.
I can't testing the light since the supplier is in another country and
these aren't still available in my country.
But before I spend a few hundred dollars on LED lights, I first want
to make sure that these things are bright. They should be at least as
bright as CFLs or incandescents or else I won't be getting those.
What are your experiences with LED bulbs and LED tubes?
How do they compare with CFLs and incandescents?
LEDs are said to be directional and more focused at smaller angles.
They may be good when used as night lights but I'm not sure how
capable they are at lighting a dark room for reading.
I know they are energy efficient but are they good replacements for
CFLs or incandescents?
The bulbs I'm ordering have either 12, 18, 32 and 48 pieces LEDs in a
single bulb.
And the LED tubes have 170++ or 276 pieces of LEDs.
Do you think they are any good?
I've read a lot on LEDs but I'm not sure what kind I should be looking
for.
The old LEDs are the ones used for indicator lights in electronics and
appliances.
Then came bright LEDs like the ones used for flashlights.
Then Luxeon and whatever kinds that I don't know much of....... |
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| JB... |
| Posted: Tue Jun 17, 2008 4:09 pm |
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<lethaldriver at (no spam) gmail.com> wrote in message
news:a77158a3-b09d-41b3-b6fe-ce7510f018c3 at (no spam) v1g2000pra.googlegroups.com...
Quote: I'm buying a couple of LED bulbs and LED tubes (direct replacements
for fluorescent tube lights and doesn't require any ballasts)
The supplier told me that their LEDs have CREE or Jinyuan (Taiwan)
chips.
Before you even consider these, read
http://www.netl.doe.gov/ssl/CALiPER-Program.htm
JB |
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| Victor Roberts... |
| Posted: Tue Jun 17, 2008 8:30 pm |
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On Tue, 17 Jun 2008 05:35:26 -0700 (PDT),
lethaldriver at (no spam) gmail.com wrote:
Quote: I'm buying a couple of LED bulbs and LED tubes (direct replacements
for fluorescent tube lights and doesn't require any ballasts)
The supplier told me that their LEDs have CREE or Jinyuan (Taiwan)
chips.
Even if true, how does that help?
Quote: I can't testing the light since the supplier is in another country and
these aren't still available in my country.
Then you have a big problem.
Quote: But before I spend a few hundred dollars on LED lights, I first want
to make sure that these things are bright. They should be at least as
bright as CFLs or incandescents or else I won't be getting those.
Why do you want to spend a few hundred dollars on
replacements for lamps that cost, at most, a few dollars
each?
Quote: What are your experiences with LED bulbs and LED tubes?
How do they compare with CFLs and incandescents?
The test data I have seen, all from the DOE's CALiPER
program shows that none of the LED "replacement lamps" meets
the published specifications. One LED downlight (which
actually might be considered a replacement lamp) is more
efficient than the best CFL alternative, but that is the
exception rather than the rule.
Quote: LEDs are said to be directional and more focused at smaller angles.
They may be good when used as night lights but I'm not sure how
capable they are at lighting a dark room for reading.
They are better than night lights. I use an LED-based
reading lamp attached to the headboard of my bed. There is
no CFL that is small enough for that application and the
LED-based lamp beats any incandescent. However, the same
cannot be said when LEDs are compared against CFLs and
especially not when they are compared against 4-foot linear
fluorescent lamps.
Quote: I know they are energy efficient but are they good replacements for
CFLs or incandescents?
They are generally NOT more energy efficient than CFLs or
linear fluorescent lamps. They may use less energy, but
they also produce a lot less light.
Quote: The bulbs I'm ordering have either 12, 18, 32 and 48 pieces LEDs in a
single bulb.
And the LED tubes have 170++ or 276 pieces of LEDs.
Do you think they are any good?
Probably not.
Quote: I've read a lot on LEDs but I'm not sure what kind I should be looking
for.
You need to look for hard data on total lumen output.
Quote: The old LEDs are the ones used for indicator lights in electronics and
appliances.
Then came bright LEDs like the ones used for flashlights.
Flashlight use low power incandescent lamps. Many modern
LEDs are more efficient than these low power incandescent
lamps. That does not mean that they are more efficient than
any fluorescent lamp.
Quote: Then Luxeon and whatever kinds that I don't know much of.......
Yes, the Luxeon LEDs are very good, especially when compared
to incandescent lamps, but they are generally not better
than good CFLs and certainly not better than good linear
fluorescent lamps.
--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.
This information is provided for educational purposes only.
It may not be used in any publication or posted on any Web
site without written permission. |
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| Willy... |
| Posted: Tue Jun 17, 2008 11:43 pm |
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Guest
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<lethaldriver at (no spam) gmail.com> wrote in message
news:a77158a3-b09d-41b3-b6fe-ce7510f018c3 at (no spam) v1g2000pra.googlegroups.com...
Quote: I'm buying a couple of LED bulbs and LED tubes (direct replacements
for fluorescent tube lights and doesn't require any ballasts)
The supplier told me that their LEDs have CREE or Jinyuan (Taiwan)
chips.
I can't testing the light since the supplier is in another country and
these aren't still available in my country.
But before I spend a few hundred dollars on LED lights, I first want
to make sure that these things are bright. They should be at least as
bright as CFLs or incandescents or else I won't be getting those.
What are your experiences with LED bulbs and LED tubes?
How do they compare with CFLs and incandescents?
LEDs are said to be directional and more focused at smaller angles.
They may be good when used as night lights but I'm not sure how
capable they are at lighting a dark room for reading.
I know they are energy efficient but are they good replacements for
CFLs or incandescents?
The bulbs I'm ordering have either 12, 18, 32 and 48 pieces LEDs in a
single bulb.
And the LED tubes have 170++ or 276 pieces of LEDs.
Do you think they are any good?
I've read a lot on LEDs but I'm not sure what kind I should be looking
for.
The old LEDs are the ones used for indicator lights in electronics and
appliances.
Then came bright LEDs like the ones used for flashlights.
Then Luxeon and whatever kinds that I don't know much of.......
I'm certainly not a expert like many within this newsgroup, but I can tell
you in my real life experience, if the product I have seen most recently in
use at a university is anything like what you're referring to (and I believe
it is the same)... you will be VERY disappointed. The light will be much
less than you hoped for, and the color (and CRI) is abysmal.
Furthermore, these products have practically no heat sink, so I seriously
question the projected hours of usable life (which should be lumens at or
above 80% for the duration of their claimed life, in my opinion).
Willy |
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| Victor Roberts... |
| Posted: Wed Jun 18, 2008 6:46 am |
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On Wed, 18 Jun 2008 00:43:04 -0400, "Willy"
<wesk at (no spam) prodigy.net> wrote:
[snip]
Quote: Furthermore, these products have practically no heat sink, so I seriously
question the projected hours of usable life (which should be lumens at or
above 80% for the duration of their claimed life, in my opinion).
Willy
I agree with your 80% number, and think it should be even
higher. However, as you know, the solid state lighting
industry is currently using 70% of initial light output as
the definition of usable life.
--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.
This information is provided for educational purposes only.
It may not be used in any publication or posted on any Web
site without written permission. |
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| Willy... |
| Posted: Thu Jun 19, 2008 5:41 pm |
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Guest
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"Victor Roberts" <xxx at (no spam) lighting-research.com> wrote in message
news:3ath545s4n8h110o1jdrdbgihls8a5ntel at (no spam) 4ax.com...
Quote: On Wed, 18 Jun 2008 00:43:04 -0400, "Willy"
wesk at (no spam) prodigy.net> wrote:
[snip]
Furthermore, these products have practically no heat sink, so I seriously
question the projected hours of usable life (which should be lumens at or
above 80% for the duration of their claimed life, in my opinion).
Willy
I agree with your 80% number, and think it should be even
higher. However, as you know, the solid state lighting
industry is currently using 70% of initial light output as
the definition of usable life.
--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.
This information is provided for educational purposes only.
It may not be used in any publication or posted on any Web
site without written permission.
I didn't know that 70% had become the most recent "norm"... that's too bad,
as it really does become appreciable at that reduced level.
FEW, Cree, or least LLF, is rating their products based on the 80%
threshold, and I hope they continue to do so.
Willy |
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| Victor Roberts... |
| Posted: Fri Jun 20, 2008 12:44 pm |
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Guest
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On Thu, 19 Jun 2008 18:41:46 -0400, "Willy"
<wesk at (no spam) prodigy.net> wrote:
Quote: "Victor Roberts" <xxx at (no spam) lighting-research.com> wrote in message
news:3ath545s4n8h110o1jdrdbgihls8a5ntel at (no spam) 4ax.com...
On Wed, 18 Jun 2008 00:43:04 -0400, "Willy"
wesk at (no spam) prodigy.net> wrote:
[snip]
Furthermore, these products have practically no heat sink, so I seriously
question the projected hours of usable life (which should be lumens at or
above 80% for the duration of their claimed life, in my opinion).
Willy
I agree with your 80% number, and think it should be even
higher. However, as you know, the solid state lighting
industry is currently using 70% of initial light output as
the definition of usable life.
--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.
This information is provided for educational purposes only.
It may not be used in any publication or posted on any Web
site without written permission.
I didn't know that 70% had become the most recent "norm"... that's too bad,
as it really does become appreciable at that reduced level.
FEW, Cree, or least LLF, is rating their products based on the 80%
threshold, and I hope they continue to do so.
Willy
The LR6 may be life rated for life at 80% lumen maintenance,
but data sheets for Cree LEDs continue to use the so-called
"L70" life, which is based on 70% of initial output.
--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.
This information is provided for educational purposes only.
It may not be used in any publication or posted on any Web
site without written permission. |
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| Willy... |
| Posted: Fri Jun 20, 2008 4:36 pm |
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Guest
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"Victor Roberts" <xxx at (no spam) lighting-research.com> wrote in message
news:p1rn54976flacbo46m50d5q6c01lron2vl at (no spam) 4ax.com...
Quote: On Thu, 19 Jun 2008 18:41:46 -0400, "Willy"
wesk at (no spam) prodigy.net> wrote:
"Victor Roberts" <xxx at (no spam) lighting-research.com> wrote in message
news:3ath545s4n8h110o1jdrdbgihls8a5ntel at (no spam) 4ax.com...
On Wed, 18 Jun 2008 00:43:04 -0400, "Willy"
wesk at (no spam) prodigy.net> wrote:
[snip]
Furthermore, these products have practically no heat sink, so I
seriously
question the projected hours of usable life (which should be lumens at
or
above 80% for the duration of their claimed life, in my opinion).
Willy
I agree with your 80% number, and think it should be even
higher. However, as you know, the solid state lighting
industry is currently using 70% of initial light output as
the definition of usable life.
--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.
This information is provided for educational purposes only.
It may not be used in any publication or posted on any Web
site without written permission.
I didn't know that 70% had become the most recent "norm"... that's too
bad,
as it really does become appreciable at that reduced level.
FEW, Cree, or least LLF, is rating their products based on the 80%
threshold, and I hope they continue to do so.
Willy
The LR6 may be life rated for life at 80% lumen maintenance,
but data sheets for Cree LEDs continue to use the so-called
"L70" life, which is based on 70% of initial output.
--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.
This information is provided for educational purposes only.
It may not be used in any publication or posted on any Web
site without written permission.
Thanks for letting me know that as well.... another question for
engineering when I have their attention.
Willy |
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