[ale] More on LEDs...

Ron Frazier (ALE) atllinuxenthinfo at techstarship.com
Tue Aug 13 00:18:29 EDT 2013


Hi all,

(part 2 of 2)

See a few more comments inline below.

Sincerely,

Ron


"Michael H. Warfield" <mhw at WittsEnd.com> wrote:

>On Mon, 2013-08-12 at 08:05 -0400, Jim Kinney wrote:
>> If it says X watts and Y lumens, it's a safe bet that the average
>> production run will hit those specs. What's harder to gauge is how
>> many lumens is needed for a task. For that, I would take various
>bulbs
>> on hand and test. 

My chart can help with that if you know what you'd need in terms of incandescents.  For example, 75 W incandescents should produce around 1200 lumens.  If you need 4 of those for a ceiling fan, you'd need about 4800 lumens at the same color temperature as the incandescents.

>
>If it says "X" watts, I would take that as the power it is expected to
>consume and less is better, all other things being held equal.  I'm
>going to give very little credence to "equivalent to ZZ watt bulb"
>claims, as that can be much much too subjective.  The hard numbers are
>power consumed, lumens produced, color temperature and life expectancy.
>The efficiency is rated in lumens per watt.  The life expectancy is
>rated in the age at which it retains 70% of it's output.  Life
>expectancy (for {C}FL's and LED's) is typically derated for a duty
>cycle
>of 3 hours use per day (Kitchens?  Seriously - get real - more like 12.
>Bedrooms will probably never burn out.  My office - 16 hours per day
>min.).  If the packaging doesn't have the "hard numbers" on it, then
>it's "no sale" for my cart.
>

You can multiply the hours * days for projected lifetime.  That's not necessarily the same as the warranty.  Many packages say life will be shorter if you let it get hot.  That may affect the warranty too.  Judging from some of the huge heat sinks on these things, that must be a problem.  The higher the lumens / W rating, the more efficient it is and the less of a heat problem you'll have for a given lumen output.

>The things I pay most attention to are lumens out and color
>temperature.
>A given number of lumens at one color temperature are NOT going to look
>(subjectively) the same brightness as the same number of lumens at
>another color temperature.  The "cool white" (which is, ironically, a
>higher color temperature than a "warm white") is going to look brighter
>due to the sensitivity of the eye to greens and blues in the higher
>temperature color.
>
>Cool white is also often referred to as "bright white" while warm white
>is often referred to as "soft white".  Grow bulbs and plant bulbs are
>often in the middle and rich in the greens and blues.  According to the
>Philips tube jacket from my "Natural Sunlight" 4' FL plant bulbs, they
>consider "Natural" (plant / grow) to be 5000K and "Daylight" to be
>6500K
>while they rate "soft white" to be 3000K.  DON'T go by color names.  Go
>by color temperature (K / Kelvin), which is better defined as it's the
>"black body radiation" color spectrum curve of a given temperature. 
>The
>cooler color temps (4000-5000K) seem to relate to slightly higher
>lumens
>per watt, probably due to less need for color shape filtering to
>produce
>the warmer white tones.
>

2700 K most closely approximates the old style incandescent that most people are used to.

Photography buffs, if you're taking pictures indoors, be sure to set your camera's controls to the proper lighting setting or your people will look weird.  The setting for a 2700 K bulb is probably labeled as tungsten or incandescent.  PS, I know just enough about photography to be really dangerous.

You may wish to also consider the color rendering index or CRI.  Some packages state this, some don't.  This relates to the accuracy of the color spectrum compared to that of a blackbody radiator which gets a perfect score of 100.  The packages that mention this at all generally rave on about being 80 or more.

http://en.wikipedia.org/wiki/Color_rendering_index

>I'm now starting to look over the cost of replacement 4' tubes for the
>4' FL fixtures.  Looks like they're in the $30-$40 range per tube with
>slightly lower lumens (but some of those lost lumens from the FL tubes
>are IR and UV range).  Most of the long-tube LED FL replacements are
>chiming in at 80-100 lumens per watt at 18W - 23W per tube for a
>4' (40W) FL replacement.  We're getting there.  We're getting there
>real
>quick.  "Shop light" FL tubes are typically 4000K-5000K color temp.
>Living space, most people seem to like 2700K - 3000K warm whites like
>the old incandescents and lamps of yore...  I like my office at 5000K.
>
>> Wife groused about the bedside lamp being too dim. I vacuumed the cat
>> fur off the shade and got a noticeable difference. Seems the black
>> cats have been polishing the shade on the inside :-)
>
>Yeah there's always that.  I always have to be careful, too, when
>putting new bulbs in fixture sets because the older bulbs (particularly
>CFLs) are going to look dimmer because they are dimmer as they age.
>CFL's and FL's age and dim much faster than LEDs.
>
>Just showed off something to June earlier today.  When she got back
>home, the kitchen can lights were off.  I looked at her and said "and
>this is the REAL REASON I like LED's" as I flipped the cluster on at
>low
>dim.  The CFL's in the 3 cans were this dim angry orange glow as they
>struggled to warm up.  The LED in the 4th can was immediately on the
>job
>and bright at its low level.  Cranked the dimmer up and the CFL's where
>STILL struggling to catch up (but doing much better).  In 5 minutes or
>so (depending on dimmer setting) they'll catch up.  But LED's will even
>beat incandescents in coming up to full output and dimmer slope is very
>smooth.
>
>I'm going to work up a minimum inventory now of new "spare bulbs" that
>are all LED and begin rotating them in.  I still have some (too many)
>PAR 30s CFLs for our smaller can lights and accent lights.  Our outdoor
>floods are all CFLs and that will be pricey to replace at current
>prices
>but they're all relatively new and I can put them off a year or two as
>well.  As they get cheaper, they get cheaper, but I'm never in a rush
>to
>run out and buy and I can rotate them into service as I need them.  I
>don't HAVE TO replace everything all in one rush.  We've still got some
>incandescent bulbs till burning bright.  When they go, they go.
>
>I feel we're now at the saddle point in the curve, the break-even point
>where, even if it's more expensive up-front, the longer term return on
>investment in LED's makes them more than worth while.  If you can
>afford
>to take the up front hit or can stretch it out while you rotate them
>in,
>it's now worth the effort.  Up till now, these have been "experiments"
>for me.  Now, I'm convinced and a believer.  I've convinced myself that
>this is the way to go.
>
>My last challenge (and this is a killer) is that bloody 500W Quartz
>Halogen Flood in the back.  We're NOT there YET.  Not residential, net
>quite yet.

Not being entirely serious here, but, get 8 ea 60 W equivalent spot / flood bulbs and gang them together on a board.  And, possibly point that from off to the side at a 2' aluminum parabolic reflector.  Again, not being totally serious but it would be a cool experiment.  On a more practical note, get one of the off the shelf reflector fixtures from the hardware store which already has a semiparabolic reflector and put that Sylvania 100 W replacement in it and see what happens.  You can get CFL coil bulbs that are the equivalent of 150 - 300 W incandescents.  Two of those in reflector fixtures might be enough.

I understand they're already making street lights using leds.  Those would have to have the equivalent light of at least a 250 W mercury vapor bulb or something, I would think.  I wonder what those cost.

Googling 500 W equivalent led flood - yields some interesting results.

This item looks cool:

http://www.google.com/url?q=http://www.bordenagencies.com/pdf/lind/Flood%2520Lights,%2520Docklights,%2520String%2520Lights/Floodlights/BEACON%2520LIGHT/Lind%2520Equipment%2520-%2520Beacon%2520Light%2520Dual%2520Head.pdf&sa=U&ei=M6IJUveoBIWyygHJyoCoDw&ved=0CEQQFjAEOB4&usg=AFQjCNFakD65lDUQaEptpUnCL9JMpUKYfA

It's a 100 W (actual) two lamp fixture that claims to put out 10,000 lumens for 50,000 hours.

>> On Aug 11, 2013 5:21 PM, "Ron Frazier (ALE)"
>> <atllinuxenthinfo at techstarship.com> wrote:

-snip-

>>         
>>         Incandescent Bulb Output Chart
>>         
>>         Power (W) ----- Output (lm) ----- Acceptable +/- 10%
>>         5         -----   25        -----   23 -   28
>>         15        -----  110        -----   99 -  121
>>         25        -----  200        -----  180 -  220
>>         40        -----  500        -----  450 -  550
>>         60        -----  850        -----  765 -  935
>>         75        ----- 1200        ----- 1080 - 1320
>>         100       ----- 1700        ----- 1530 - 1870
>>         150       ----- 2850        ----- 2565 - 3135

-snip-



--

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Ron Frazier
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