Philips L-Prize lamp

[jharkin]

Some of you might remember last year I reported trying out LED based down lights (Ecosmart/Cree CR6s and Ecosmart/Lighting Science PAR30 bulbs) when I was replacing all the can lights in my kitchen and dining room last year as part of an insulation/efficiency upgrade. Well a year later and I am very happy with the performance and light output of those units… soooo much better than CFL … that I decided to try out some more LEDs.


Presenting the (broken link removed)!

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I have a couple of fixtures where CFLs burn out often (bath) and the local electric company offers the Philips L-Prize bulb at a subsides price of $25 so I decided to try a couple.

My overall impression…. This is a VERY nice bulb. Brighter than CFL…maybe brighter than incandescent, minimal eyestrain, extremely low power consumption. The power savings is better than reported and in fact this bulb measured a 40% improvement even versus an equivalent CFL!

Even at the discounted $25 price it’s a bit of a luxury but I’d say worth it at this time for closed fixtures that get a lot of run time and eat CFLs, or maybe one or two around the house in your favorite reading lamp. I wouldn't shell out the full $49 for one.

For now I put in 3 – one in the bath vanity, and two in the table lamps in our den that get more use than any other lamp in the house. This is where I sit and read in the evening.

​

When the price comes under $10 I will seriously think about starting to swap them out around the house. The only question at this point is will something even better come along before these hit break even?

Since I know you all will appreciate it, I did some quick tests… read on to part 2.

 

[jharkin]

First impressions: The bulb is a LOT brighter than the 13watt CFL we had in the same lamp. In fact it feels like going up a size. My wife’s first impression was “wow that’s bright” but after a day we really like the improved lighting, seems like the room was too dim before.

I am surprised thy omitted the big heat sink from the base, as it still gets quite hot… Not as hot as an incandescent obviously but still too hot to touch comfortably, I measured 127F on the white base with a cheap IR thermometer after an hour of run time.

To give you an idea of the relative brightness here are side by side shots of 3 roughly equivalent lamps – the L-Prize LED, a 13watt CFL and a 60watt incandescent (this one is a rough service bulb, it was all I had). All 3 bulbs are hooked up to the same power strip, and warmed up for 5 minutes. The voltage in my house is not great - fluctuating around 110-113vac at time of test.

​

Now looking at each lamp. I tested each on a kil-a-watt after a short (3-5 min) warmup.

Incandescent: GE 60 watt rough service (Hungary) $ a buck?
Rated at 60 watts, 500 lumens and 2000hours @ 130v (or 380 lumens & 5400h @ 120v)
Hooked up to a kil-a-watt I measured
· 46watt/46VA
· PF = 1.0 (expected)
· @ 113.7vac




CFL: Westpointe 13 watt “60 watt equivalent” (China) $3
Rated at 13 watts, 900 lumens, ? CRI, 2700k color temperature and 12,000 hours
Measured:
· 12watt / 20VA
· PF = 0.58
· @ 112.2vac



LED: (broken link removed) (USA) $35-50 on amazon or $25 subsidized
Rated at 9.5 watts, 940 lumens, 92 CRI, 2700k color temperature and 25,000 hour
Measured:
· 7watt / 8VA
· PF = 0.85
· @ 110.0vac

 

[begreen]

Nice comparison. What is with the declining voltage? We are usually at 120-122vac.

I'm hoping to see LEDs come down a lot in price. Right now they are just not cost competitive with CFLs for our electric rates. We stopped buying regular incandescents years ago. The 130v bulb is not a fair comparison for light output. A better comparison incandescent bulb would be an A-19, Philips EcoAdvantage 60w equiv (43w actual) halogen @ 790 lumens. Home Depot sells a 2 pack for $3.48, or $1.74 each. I prefer them in some locations like bathroom lights where they get switched on and off frequently.

 

[velvetfoot]

I saw some interesting led bulbs last weekend in a restaurant. The chandeliers and wall sconces had somewhat interesting looking bulbs, so I reached up there and it was cool! I asked the waiter, and he said, yes, they were leds. I think that is a great application for leds because there is no way a cf would work there and nice looking chandeliers can be used without suffering any pains of (misplaced?) guilt. Of course, if you have those ritzy ditzy chandeliers, you can probably afford the price of all those led bulbs.

 

[jharkin]

The power quality around here is not great... I rarely see anything over 120v. Its not my house wiring as we have a new 200A service and Ive redone most of the circuits in the house... While I was doing the test my wife was baking Christmas cookies so the voltage would bounce up and down as the oven element cycled i think.

I agree rating on that incandescent is silly... dont know why they spec 130v. Its just he only "60 watt" bulb I had lying around - the only thing I still use them in are shop lights and the garage door openers.

 

[woodgeek]

I got three of the L-prize guys for my dining room...a place I want good color, lumens and deep dimability. I also got the special dimmer made for LED's. Very nice. Amazon had them marked down on Black Friday.

I put the previous gen Phillips in my outdoor light last year. So far so good. Instant on in the cold is good, as is the eff running 8 hours/night on a timer.

When you get very close to the L-prize guys...you can hear them buzzing a little. Not noticeable in normal use.

 

[woodgeek]

The power quality around here is not great... I rarely see anything over 120v. Its not my house wiring as we have a new 200A service and Ive redone most of the circuits in the house... While I was doing the test my wife was baking Christmas cookies so the voltage would bounce up and down as the oven element cycled i think.

I agree rating on that incandescent is silly... dont know why they spec 130v. Its just he only "60 watt" bulb I had lying around - the only thing I still use them in are shop lights and the garage door openers.

When I had 200A put in, the utility refused to upgrade the aerial line (which they own). Seemed kinda small gauge to me. True or not, my electrician said the utility 'liked' the aerial lines to be undersized in case of fault (i.e a hard short in the house). I know the snow on the line melts, (esp when I pull 20 kW).

 

[jharkin]

When I had 200A put in, the utility refused to upgrade the aerial line (which they own). Seemed kinda small gauge to me. True or not, my electrician said the utility 'liked' the aerial lines to be undersized in case of fault (i.e a hard short in the house). I know the snow on the line melts, (esp when I pull 20 kW).

Same thing happened with us. The aerial lines look small compared to the line down from the weatherhead which is something like 4/0 Al. Ive heard some electricians say they are allowed to undersize the areal lines because they get more cooling in free air. Not sure what to believe, but its annoying nonetheless.

 

[jharkin]

Another anecdotal note - I put the 3rd bulb as mentioned in the bath, in a NuTone ceiling fanlight fixture. Previously I had a 23watt (100w equiv) CFL in there to brighten up the room. Switching to the LED is just as bright if not brighter.

But begreen is right - these are not cost effective even at high NE elec rates. Its more of a comfort / experimental thing right now.

 

[velvetfoot]

Are these the Phillips that are yellow when off?

 

[jharkin]

They are, but I think the previous generation Philips led also were.

 

[woodgeek]

Are these the Phillips that are yellow when off?

The old generation have the yellow phosphors and a 'silver' tone body...the L-prize have v similar yellow phosphors, white bodies, and are 20-30% higher lumens/Watt and much better color. The L-prize are sensibly indistinguishable from IC bulbs on color render, and almost 2X as eff as CFL, and fully dimmable (at least with a designed dimmer).

 

[woodgeek]

If you want more info, there is a teardown here:

http://www.molalla.net/members/leeper/L prize bulb.htm

Looks like they get good color by mixing different color LEDs, and high Lumens/watt by driven more LEDs at lower than max rated power.

 

[seige101]

Been buying these (broken link removed to http://www.homedepot.com/h_d1/N-5yc1v/R-202668646/h_d2/ProductDisplay?catalogId=10053&langId=-1&keyword=led+light+bulb&storeId=10051)

locally they are 19.95 a piece

I would say they put out the light equivalent of a traditional 75 watt incandescent. Every time i make a trip to the depot i buy one. Replaced 7 bulbs in the house in the last 7 months. Also upgraded the recessed lighting to these (broken link removed to http://www.homedepot.com/h_d1/N-5yc1v/R-202240934/h_d2/ProductDisplay?catalogId=10053&langId=-1&keyword=led+retrofit&storeId=10051) locally they are 24.95

Love the led bulbs, instant 100% brightness and dimmable unlike the CFL 'dimmable' lamps that have like 2 dimmer settings, kinda on and full brightness.

As an added bonus when i replaced the outside light with an LED bulb virtually no bugs are attracted to it.

For the 2 island pennant lights i used these (broken link removed to http://www.homedepot.com/h_d1/N-5yc1v/R-202188260/h_d2/ProductDisplay?catalogId=10053&langId=-1&keyword=led+light+bulb&storeId=10051) They are now on from dusk until around 10 or so pm

 

[raybonz]

Same thing happened with us. The aerial lines look small compared to the line down from the weatherhead which is something like 4/0 Al. Ive heard some electricians say they are allowed to undersize the areal lines because they get more cooling in free air. Not sure what to believe, but its annoying nonetheless.

(broken link removed to http://www.sfasoft.com/look/32) yes the ampacity is much higher in free air.. You probably have XHHW cable but you need to know to determine the ampacity. As for serious voltage fluctuations there may be a bad or overheated high resistance connection at the street. This happened here years ago and after re-torquing my meter socket which was tight the power company found an overheated insulug connector which is essentially a butt splice crimp connector. My voltage problem was much worse than yours though as I would see my voltage drop to 70-80 volts when it got really bad with any heavier load on! Could be you're seeing the start of a bigger problem so keep an eye on it..

Ray

 

[raybonz]

The power quality around here is not great... I rarely see anything over 120v. Its not my house wiring as we have a new 200A service and Ive redone most of the circuits in the house... While I was doing the test my wife was baking Christmas cookies so the voltage would bounce up and down as the oven element cycled i think.

I agree rating on that incandescent is silly... dont know why they spec 130v. Its just he only "60 watt" bulb I had lying around - the only thing I still use them in are shop lights and the garage door openers.

Quote from another source:

"The thicker filament in a 130 volt bulb, when operated on typical 110-120 line voltage, provides less resistance to the electrical current flowing through the filament. As a result, the bulb burns cooler, uses less energy (watts), and lasts longer; however, as a trade-off, the bulb is also slightly dimmer and has a lower (more yellow) color temperature."

Ray

 

[raybonz]

My concern with the LED lamps are the power supply that feeds the LED's more than the LED's themselves. LED's operate on low voltage DC power created by a built-in power supply. I deal with high quality regulated DC power supplies in my work and they will fail in approximately 10 years and I don't expect the power supply in a $10.00 lamp to last as long as a high quality power supply.I guess we will have to wait to see if the new LED lamps withstand the test of time..

Ray

 

[jebatty]

I'm satisfied with my first foray into LED lighting. EarthLED had a closeout on 40w equivalent LED's at $5.00/each. Light is very white, which is OK for 3 wall sconces + 4 track lights, with a traditional dimmer, that provide ambiance off a fireplace wall. They are not bright enough for task lighting or for reading, but work OK as now being used. My "problem" is that my CFL's are lasting too long -- must have lucked out and got some good ones -- some of our CFL's now have been in place for 15 years, and they are well used can lights which are "on" a lot in our kitchen.

Is there any new technology after LED's?

 

[raybonz]

I'm satisfied with my first foray into LED lighting. EarthLED had a closeout on 40w equivalent LED's at $5.00/each. Light is very white, which is OK for 3 wall sconces + 4 track lights, with a traditional dimmer, that provide ambiance off a fireplace wall. They are not bright enough for task lighting or for reading, but work OK as now being used. My "problem" is that my CFL's are lasting too long -- must have lucked out and got some good ones -- some of our CFL's now have been in place for 15 years, and they are well used can lights which are "on" a lot in our kitchen.

Is there any new technology after LED's?

Fluorescent lamps last much longer if not cycled on and off frequently.

Ray

 

[woodgeek]

I'm satisfied with my first foray into LED lighting. EarthLED had a closeout on 40w equivalent LED's at $5.00/each. Light is very white, which is OK for 3 wall sconces + 4 track lights, with a traditional dimmer, that provide ambiance off a fireplace wall. They are not bright enough for task lighting or for reading, but work OK as now being used. My "problem" is that my CFL's are lasting too long -- must have lucked out and got some good ones -- some of our CFL's now have been in place for 15 years, and they are well used can lights which are "on" a lot in our kitchen.

Is there any new technology after LED's?

I think LEDs have a lot of evolution ahead of them. Any breakthroughs will likely be different solid state devices (i.e. lasers or different materials) which will have the same form factor to the end user. Think microprocessor chips...revolutionary changes in engineering, right under our noses, but invisible to us.

These L-prize guys are crossing the benchmark of 100 lumens/watt, for the first time in something that looks like an edison bulb with good color. But there is plenty of room for improvement. Physical limits are around 500-600 lumens/watt. There are plenty of solid-state devices in the lab now that run 200-250 lum/W.

 

[jharkin]

http://en.wikipedia.org/wiki/Luminous_efficacy#Lighting_efficiency

I don't know how good the reference is but it puts the limit for LED at 300 LM/w


Funny thing about microprocessors.... That is an area that is already approaching physical limits, there is not much smaller they can go on the transistor size and we are at that stage where each addition step down in gate size comes at a big cost in power efficiency. Hence you see most of the advancements now are from parallelization - everything is dual, quad, six core or more and video cards are implementing hundreds of processors.

 

[begreen]

jebatty, that is our problem too. I stocked up on compact fluorescents for our recessed cans, mostly in the kitchen. It doesn't get direct sunlight so the wife has them going 12 hrs a day in the winter. I date the bulbs and we are getting 2-3 yrs out of them which means we are set for the next 4 yrs or so. Maybe by then LEDs will come down. I saw the light output of the Cree 6 and really liked it, but it will have to be a lot less expensive for me to go for it.

 

[woodgeek]

http://en.wikipedia.org/wiki/Luminous_efficacy#Lighting_efficiency
I don't know how good the reference is but it puts the limit for LED at 300 LM/w

Agreed. Still, a 3X improvement from here (300lum/W) gets a 60W IC equivalent, now in a 9.5W L-prize, down to a 3.2W (future) LED bulb. Imagine the light of a 60W IC bulb coming from something that uses less than the (4W) nightlights I grew up with!

Funny thing about microprocessors.... That is an area that is already approaching physical limits, there is not much smaller they can go on the transistor size and we are at that stage where each addition step down in gate size comes at a big cost in power efficiency. Hence you see most of the advancements now are from parallelization - everything is dual, quad, six core or more and video cards are implementing hundreds of processors.

I don't consider parallelization evidence for physical limits....just shows another way of engineering the desired 'ends'.
Most people don't know/care their CPUs are multicore. End users see the performance/price just keeps going up.

 

[jharkin]

I don't consider parallelization evidence for physical limits....just shows another way of engineering the desired 'ends'.
Most people don't know/care their CPUs are multicore. End users see the performance/price just keeps going up.

Maybe its not solely due, but definitely a devolpment that has come as it gets difficult to manage ever larger and faster chips.

http://en.wikipedia.org/wiki/Moore's_law#Ultimate_limits_of_the_law
http://en.wikipedia.org/wiki/Moore's_law#Parallelism_and_Moore.27s_law

We are pretty close to atomic scale with the current 22nm process in the newest chips. Not much smaller they can go, placing limits on how much faster single Chips can go. The compute power per watt efficiency today is horrible compared to 10 years ago, hence the need for massive heatsinks on modern systems. Parralel CPUs is one way around this limit, but we are still catching up with software that can really take advantage of massive parralelization... For home users at least.

Eventually the way forward will be in quantum or optical computing, but that is a while off.

 

[Laszlo]

When the price comes under $10 I will seriously think about starting to swap them out around the house. The only question at this point is will something even better come along before these hit break even?

You're in luck! Massachusetts and Rhode Island utility customers can now buy up to twelve L-Prize bulbs for $10 each instead of $25. And according to my calculations, when replacing 60-watt incandescents, these will have a payback period of 1100 hours use given the cost of $0.1437 per kWh (the avg MA residential rate in Oct 2012). If you have any lights on 12 hours/day then that's a return-on-investment of only 3 months! I've made a Google Docs spreadsheet comparing various types of A19 bulbs and their TCO over 30,000 hours. You can save a personal copy, then put in your own values to update the graphs to reflect your own electric rates and bulb prices.