A lingering limitation on LED lighting in 2012 is power
(ie the amount of light produced). As of 2007 I liked my lighting bright,
so for example my then desk lamp in my study was a 20W 1200 lumen mains CFL.
As of the turn of 2010 I starterd using the 7W mains 'cool white'
EQ60 in an anglepoise, and as of 2012 we now have 7W and 10W
(roughly equivalent to 40W and 60W incandescents)
in several fittings around the house.
Note that although the latest round of off-the-shelf LED technology in 2011--12
is passing the efficiency of CFL at 60lm/W, the theoretical maximum efficiency
of 'white' lighting is about four times this, so we have some way to go still!
And note that LED lamps have no 'warm-up' time, which even new CFLs exhibit.
LED lights, often as drop-in replacements for miniature halogen display lamps,
are becoming widely available in the high-street as well as over the Internet,
and are passing the efficiency of the best widespread alternative,
so we could be on the cusp of a small but well-lit revolution!
The main barriers to household use that remain as at the start of 2012 are
cost (several times that of CFL)
and maximum light output (50W halogen equivalent LEDs are still rare).
The relative cost of LED compared to CFL is probably not as bad as it looks,
because the very long lifetime of LED bulbs may well compensate
(at several years of continuous operation for LEDs vs maybe 1 or 2 for CFL).
And maximum power? It's relatively easy to match incandescent lumens up to ~60W
for domestic lighting, and as high as you like for commercial/industrial.
Mains LED Lighting: Mini Reviews
I'm testing a wide variety of retail mains (240V) LEDs for acceptability,
power, etc (up to 2009 available Wattage and lumens has been limited per bulb),
see my mini reviews below...
Children's Nightlights
Both our children's nightlights as of 2009 are (0.5W) LED mains socket plug-ins,
a tiny 1/10th the consumption of the incandescent type that we used before.
Note that they don't actually seem to draw less power when they turn off
in daytime, and we turn them off manually anyway.
3W GU10 6000K 'Cool' White as Child's Bedside Light
Our young daughter's bedside light is a 3W mains GU10 LED in a gooseneck lamp;
a "cool" (600K) from 2008 up to late 2010
(replaced Sept 2010 with the Livarno 3W warm white),
directed up at the ceiling as indirect lighting,
and works well for her.
It's officially my office soldering/closework desk/work spotlight,
but I don't need it most of the time and it works well in this alternate role.
When I was young my bedside light was a 60W incandescent;
this is safer and cooler and probably represents a distinct energy saving,
and should last a long time.
My daughter is also tester for other GU10/240V lights that cross my path!
5W ES27 (screw) Spotlight 'Cool' White in Kitchen
We eventually found a good site in our kitchen for the 5W LED "cool" (6000K)
spot from UltraLeds.co.uk (which was the highest power available ~2007),
marked on the side "civilight", and though it is a little weak/watery,
it works fine with the blue elements of the decor.
(One issue with a light that is going to last many many years and cost lots
is that we'll have to think about and plan more carefully what we buy,
whereas before we knew we'd be buying a new bulb inside a year anyway,
and didn't have much choice in light colour nor CRI/rendering issues.)
Note: this bulb seems to cause significant interference on a VHF FM
radio about 2m away, unlike the CFLs in the same spotlight lighting strip.
This item failed after a little over 2 years
with Ultraleds offering no help even though one might find this early failure
"not fit for purpose".
2012/02/01: I finally disassembled the unit to extract the board with 5 series
LEDs, which draws 60mA@14V (0.8W), 200mA@15V (3W), 340mA@16V (5W+),
ie about 3.2V/340mA for rated output, if heatsinked on the original case.
So I could use it as part of my LiFePO4 battery dump load with care.
2W ES14 (small screw) Candle 'Warm' White as Child's Reading Light
As of the end of January 2010 the 20W halogen lamp
that we were reading to younger child by physically broke and was unsafe,
so we spent £4 on a small simple bedside E14/ES14 (14mm Edison Screw)
bedside lamp,
and although it won't be on much and we have spare ES14 incandescents
I thought I'd see what LED lights were available retail in our local shops.
At least two shops had 2W-rated candle-style lights available for ~£10,
so I bought the Philips "AccentWhite" warm white from John Lewis.
(Actual consumption seems to be 1.6W, with a power factor of ~0.4.)
Nothing of a higher rating was (yet) available in that fitting in LED,
though 7W/8W CFLs such as the one in my own bedside light are.
Nominally it has 20 years' life (20,000h) though I suspect it might outlast me!
Note that this lamp takes a second or so to come on
(though is then at full brightness, so is not 'warming up' like some CFLs),
which can occasionally be slightly disconcerting.
2011/12/21 the 2W Philips lamp was replaced with a much brighter
Clas Ohlson 3W 250lm golfball
(36-4641)
lamp.
Light Planet EQ60 and 7W GU10 Spotlight
Preliminary testing of a pre-production 'warm white' EQ60
(in an anglepoise ES27 fitting)
is very satisfactory; pleasant solid light, though consumption >7.5W.
I asked a colleague and their spouse to try Light Planet's
7W warm-white spot
(GU10/240V, 355lm, 2850K--3000K, CRI 70, 120° beam angle),
their spouse being a medic who likes everything "like an operating theatre"
and thus wants a decent volume and 'quality' of light,
and they were sufficiently impressed to replace all the halogens in that room
with these devices!
Indeed, they report the halogen bulbs as looking weak and watery by comparison.
(Note that a typical 50W halogen apparently emits up to 900 lumen, 35W/~600lm,
though I see 12lm/W typical quoted, and light temperature of ~3000K is common.)
Another colleague, doing an energy-sensitive refit of his house,
found the EQ60 'warm white' too yellow and too narrow a beam for his purposes,
but found the GU10 spot's output beam remarkably wide and even.
Another tester, who had complained about her 'too yellow' CFLs causing headaches
found the 'cool' EQ60 too harsh and clinical.
The EQ60 production-run packaging as of March 2010
is much cleaner and less fussy than before
though in my opinion should probably be labelled with:
- lumens output,
- colour temperature
(though that is marked on the bulb itself, 5000K for 'cool'),
- possibly 8W power consumption since it is at least sometimes
much closer to that the the 7W printed, and
- an EU energy-efficiency label (A-G) when one is available.
I think that a more 'neutral' (say 4000K) tone would be a useful addition
to the range for both the EQs and the V3s (see below),
though Light Planet feels there would be some obstacles:
Trying to produce a third product in the range would be difficult, due to the
commercial commitments on the current chip sets. May be able to introduce them
at a later date.
We have been testing a couple of the (warm) "V3 Ultimate GU10 LED Spot Lights"
in a specially-installed 'test' lighting fixture in our kitchen.
We're getting less lumens per Watt in this GU10 style than with the EQ60,
but that's in part because the GU10 fitting is hostile to non-incandescent
technology in general being designed to retain heat which is good
for halogens but bad for LEDs/CFL. CFLs in this format seem to be limited
to ~50lm/W also.
The V3 light quality is pleasant,
and unlike the CFL GU10 that we are comparing with,
is almost instant-on (within a second). The 'warm' tone suits our yellow walls.
The beam angle is 120° and thus barely a 'spot' in fact,
which also suits our purposes fine.
When alongside an Omicron 11W GU10 CFL (2700K),
the LED is faster to come on (almost instant, with no "warm-up" phase)
and of very similar colour after a few minutes when the CFL has stabilised.
Both are fairly pleasing to the eye in terms of design and appearance,
though the CFL has a longer body that protrudes from the fitting,
so the LED wins on that element.
We'll have to see if we still like the light tone in the darker months of winter
(testing has been spring/summer) with less bright natural (cooler) light around.
However, I can report that it is pleasant to use at night, warm and full,
unlike the watery 5W 'cool' LED light we tried in a similar position.
We like the V3, and would only hope for a greater efficiency (lm/W)
and greater power output (ie more light) in future revisions.
Philips Econic 3W GU10 Spotlight
The first thing to be careful is that there are apparently as at 2010/08/10
two versions of this in circulation, one marked 15 year life and the other 25,
and neither marked on the packaging with lumens output,
and Philips' own site is coy too,
and their customer enquiries initially suggested 300lm output
which would be remarkable,
and then a week later called me back to say 220lm.
This confusion is unhelpful at the very least, and I expect better of Philips.
I have borrowed one of the devices labelled as 25-year life (25,000 hours),
which I take to be the same as this
Argos 432/9244 lamp,
which is given as 250lm, ie ~80lm/W, thus beating the V3 in efficiency if so.
Certainly by eye the light output is not remarkably different from the 7W V3,
even allowing for the slightly different light colour and very different beam
(a spot at the 25° claimed on the packaging that I have).
This bulb is slightly shorter than the V3, at 50mm,
and does not protrude at all from our kitchen fitting.
The lamp is 'instant-on'.
My daughter preferred this 3000K/warm light over the current 6000K/cool lamp
in her bedside light.
My partner liked the light quality in our kitchen.
A friend described it as not looking
"quite so much like a gadget from an episode of 'Blake's Seven'"
compared to the V3!
This lamp seems to be matching or beating standard CFL efficiency,
which is hard to do to this style of fitting.
At £20 it's still quite expensive,
but the Argos page claims that it will last as long as
25 (35W) halogen bulbs at about £2.50 each,
so likely cost-effective even ignoring the substantial energy savings.
2011/03/03: Philip C emailed me to say "Another week, another hardware
change from Philips:"
It's this:
http://www.johnlewis.com/227266/Style.aspx,
which I think is the UK version of
http://www.p4c.philips.com/cgi-bin/dcbint/cpindex.pl?slg=en&scy=dk&ctn=872790091824300
(certainly the specs that are on the boxes match, they look the same, and the
barcode only differs slightly). As a downlight in my glass-fronted kitchen
cabinets it's much more pleasant than the prior version, with the warmer
temperature providing a similar hue to the cherry cabinet as a 35W halogen.
Subjectively, it's also pretty similar light output. However, I wouldn't use it
for more general lighting; there is a noticeable red hue (vs general warmness)
when used for room lighting, with a particular red fringe at the edge of the
fall-off cone.
Lidl Offer Livarno 3W GU10 Spotlight
On 2010/09/02 Lidl had an offer of £5.99 for 3W LED lamps,
in various fittings including GU10,
Livarno brand (EDI Light GmbH),
and claiming ~60lm/W on the box, ie about 180lm total.
This lamp certainly seems less bright than the Econic at ~250lm,
but the beam angle of 90° of this lamp cf the Econic 25°
confounds easy comparisons.
If the lumen values are correct then this Lidl lamp is less good efficiency
(ie lm/W) but much better value (lm/£)!
Both of them however do well in efficiency terms compared to CFL
(at least as good) especially given the GU10 fitting.
The light is a pleasant colour, and the multiple (15) emitters/chips
make for a less harsh 'point-source' feel.
My daughter preferred this to her previous (6000K LED) bedside lamp,
primarily because this illuminates the far end of her bed better
given its broader beam;
it seems to throw significant useful light beyond the 90° stated,
possibly in part because of its slightly domed front.
This comes on quickly, faster than the V3 for example.
Like the Econic, this claims a 25,000 hour life.
V5 7W GU10 Spotlight
Light Planet on 2010/09/16 kindly
supplied me with a "V5" 7W, 720lm, 38° beam angle, 5000K--6350K "cool",
GU10 LED sample for evaluation.
Interestingly it is rated 100V--240V AC, so suitable for markets worldwide.
The stated efficiency (~100lm/W) would put it well ahead of most CFLs.
For example, a new 7W Philips "golf-ball" "warm" SES CFL is labelled as 310lm
(and the equivalent of 31W incandescent), 10000h, 50000 on/off cycles,
and 1.4mg mercury to boot.
On the supplied scale, 720lm comes in at just under 60W incandescent.
This lamp is bright
(only a 40W or 50W GU10 halogen or good 12W CFL should be able to
match or beat its light output in that fitting),
and it is fast to come on.
One generic point about these intense point sources rather than (say) CFLs,
is that they seem much more headache-inducing when caught in peripheral vision,
so their arrangement is more critical than just what they light;
more smaller lamps, or more chips within each lamp, may help.
This particular device has 4 emitters,
whereas the Livarno light with 25% the lumens output has 15!
I have now bought the 12V (MR16) version of the V5, also cool white,
and it is every bit as bright as the mains (GU10) counterpart,
and a stained-glass artist to whom I lent it has been very happy with
its colour rendering at her work desk
even though initially taken aback by its coolness
compared to the halogens she was used to.
Clas Ohlson 7W "north light" Bayonet
For £17.99 in Clas Ohlson
I picked up on 2011/01/02 a 7W "north light" with a bayonet (B22) fitting,
labelled as 7W (40W equivalent) 470lm warm white (2700K),
and with a 'standard' bulb shape (like the Tess/EQ60s previously reviewed),
stock item 18-2314,
for test.
The packaging claims a life of 15 years (15,000 hours) at 2.7 hours use per day.
This lamp is not dimmable.
Confusingly, part of the packaging states 100--240V 50Hz
and elsewhere 220--240V; I assume that the latter is correct
though it makes no difference for my purposes.
There are other fittings and styles and wattages now available at Clas Ohlson,
such as an ES (screw) base version of this lamp,
but also SES (small screw) golf-ball and candle style lamps up to 2W,
so there is a decent range available.
None of them were displayed powered up,
and surely people are going to be reluctant to punt nearly £20
on a new technology without even being able to see what it looks like lit?
For my initial test I substituted this 7W lamp
for a very-slow-to-start and insipid 9W CFL
(CFLs of higher rating tend to be too big for the fitting)
in our hallway which is only on for short intervals
and for which instant-on is very handy,
so the current CFL was not doing very well at all.
Firstly, being the size of a standard incandescent bulb, it fits!
Secondly, the instant-on behaviour is well worth having.
Thirdly, this lamp seems noticeably brighter than the 9W CFL
even when the latter has had a while to warm up.
The light is even and warm and the lamp does the job.
It also meets with the approval of my partner!
On the strength of the performance of this lamp,
we bought a screw (ES/E27) version of this bulb
(SKU 36-4241, 7W, 470lm, Ra 85, "warm white"/2700K, £17.99)
to replace an expired 12W Philips "New Softone" CFL 2011/09/16 in the kitchen.
And 2011/10/15 one to replace a 20W CFL in the bathroom,
where its instant-on behaviour is valuable (it's rarely on for long);
though as it's noticeably dimmer than the CFL after warm-up
it may yet have to be swapped out for something a little stronger.
Clas Ohlson 4W PAR16 SES Spot
I bought a 4W SES spot for a friend to try
at his train-station coffee stall, where it replaces a 40W incandescent.
It seems a very similar level of available (warm) light, on 10% the power!
At ~8h/day use I think it may be saving him about £1/month in mid 2011,
and though not all 10 of the positions are ripe for LED replacements
(eg due to the steam belching from his fancy Italian coffee machine,
where instead we have tried halogen bulbs at a 30% or ~30p/month saving)
several of them are. They'd pay for themselves in electricity alone in
18 months, and maybe again in replacement incandescent bulbs in its
20-times-longer life (ie 20000h vs 1000h for the incandescent),
never mind avoiding the fiddle and annoyance of replacing the bulbs.
Multicolour Auto-changing GU10 LED
Just for a bit of winter silliness I've swapped out one of the GU10 (240V)
lights in the kitchen (a 11W CFL) for a
Maplin N27HA "1.5W Auto Changing Multi Colour LED GU10".
Not especially bright but the colours are indeed "vibrant" as claimed;
the kids like it.
Clas Ohlson 2W Golfballs
In December 2011 we bought 2 Clas Ohlson golfball 2W 250lm warm-white LED bulbs,
one with a small screw (SES/ES14) fitting
(36-4641)
as a signficiantly brighter replacement for the Philips "AccentWhite" 2W
in my boy's room (see above),
and the other with a bayonet (B22) fitting
(18-2313)
for the in-laws to use in place of an existing 15W incandescent night-light
which is all ~8h/night every night. They seem to like it. Should save them
~£4/y at current prices, or a 2-year payoff.
These bulbs seem comparable to or brighter than the 7W/8W CFL golfballs
we have in our house, eg in bedside lights...
Maplin LED Strip Lighting plus Extension
In 2011 I bought a basic Maplin 'decorative' LED strip lighting kit
(A07JT)
for the kitchen at the 'offer' price of ~£25, but only 'temporarily'
fixed it up, actually sticky-taped (as very lightweight) under a cupboard
above a work surface but we had not used it much as the quantity of light
was maybe not quite what was hoped for.
(One attraction of this system was that the LED strips run at 12V,
12.1V measured at the unloaded mains adaptor in fact,
so they could plausibly be driven from my off-grid 12V system if required.
The strips are nominally ~0.53W each though the adaptor is rated max 1A ie 12W.)
The kit includes a mains adaptor,
three LED (cool white) strips,
various connectors and fixings, allowing the strips to be assembled many ways.
Nicely done.
The extension kit of three more LED strips and more connectors and fixings
(A08JT)
that plugs into the existing strips and mains adaptor,
came on offer again in Jan 2012 (~£15) so I bought one and fixed up the
system properly to banish the worktop shadows between cooker and sink.
The clips and screws are easy to use (the sticky pads were beyond me),
and I'd put up the enlarged system in somewhere over half an hour.
LEDON 10W Bayonet
It has been hard to get hold of anything more than about 7W
(ie ~40W incandescent equivalent)
for standard 240V domestic bayonet or ES fittings.
I jumped at the chance to try the LEDON
(Energy Saving Trust approved)
10W bayonet mains lamp though expensive at just under £30 including VAT.
This has a 600lm output, and as advertised is 'very yellow' and to my eye
more so than other 2700K-colour-rated 'warm white' lamps,
and claims "exceptionally good colour rendering (90Ra)."
A warmer and more orange tint to it than the slightly watery Clas Ohlson 7W.
The first place we're testing it is in our small bathroom,
which long ago was lit by a 60W or 100W incandescent as I recall,
but we have had a 7W LED (~470lm) bulb there for a while which we grew used to.
My daughter and and partner both commented on the new lamp being noticeably
brighter, which should make it easier to spot dirt on us and the surfaces!
Reading in the bath was slightly hard work with the 7W lamp;
I'm hoping the new one will be an improvement there.
Non-mains Lamps
LEDs are naturally low-voltage (and DC) devices,
so work well in battery/solar installations.
IstoriaLED 4.5W 12V MR16 Warm and Cool
At the Energy Solutions Expo October 2011,
IstoriaLED
very generously gave me a couple of review samples
(one warm/2700K+, one cool/6000K+).
Both have an A+ energy rating, are 4.5W and 351lm (650 eff lm) and 50000h life.
Initial subjective testing suggests that the cool light is nearly as bright
as my 720lm/7W Aurora V5.
The cool seems much brighter than the warm (I expect some difference, but not
this much).
These feel robust and I'll update when I've had time to give them a good
workout.
Wilkinson Own-Brand 97p Solar Garden Lights
In June 2010 we thought we'd look at a simple cheap solar-powered
garden light to see if they are any use. They don't give out
a huge amount of light and there is an embedded environmental and energy cost
even if they don't need mains or batteries.
We splashed out on two of these.
These are very simple and cheap and physically small and light,
possibly using a supercapacitor inside rather than a battery,
powering a single cool-white LED pointing out the base of the unit
through a clear plastic prismatic diffuser.
The light given out is fairly weak but pleasant accent lighting;
it wouldn't much help, for example, with navigating the garden at night.
Each unit consists of a small 'amorphous' brownish solar cell on top,
a black plastic body with a thin metal covering sheet,
and a removable diffuser and spike for planting in the earth.
Under the diffuser/spike is a switch to turn the light off,
thus presumably saving its juice for another day or if packed away.
My 19-month old boy managed to disassemble and break one unit fairly easily
requiring the LED's leads to be resoldered to the board,
but all-in-all the unit seems robust for normal uses!
These could be nicely adapted to make solar-powered lights for a doll's house,
or for children's night-lights with some extension of the LED leads
(one seems to last about 4 hours when fully charged).
All were dead after a year.
Landing/Hallway Night Light
We decided that it might help our daughter find her way to the loo in the night,
and help us to get around at night without turning on the main overhead light
on our upstairs landing possibly disturbing both children,
to try a night light there.
The upstairs corridor does not have a single power socket,
so my first attempt was to try using a 3W (cool white) MR16 12V lamp
from my solar off-grid system, temporarily hooked up at the master bedroom door.
It's certainly enough to see by, even downstairs, but was too bright
and kept us awake at night. Also the power drain is a bit more than I'd like
from my off-grid system (the 'official' server drain is under 4W!).
My second attempt involves a block of 4xAA NiMH 1.2V rechargable cells,
a 470Ω resistor and a push-button toggle switch,
and a 10mm nominal 60cd (60kmcd) 3.5V white clear LED
c/o Thurmond M in Texas (thanks again) that I had available to tinker with,
all in series in a clear plastic box, sitting on a chest of drawers.
So far so good.
Circuit diagram/schematic as:
.SHX,
.pdf,
.png.
With the 4.7kΩ resistor
(up from an initial 470Ω which made the nightlight too bright)
the current draw is ~0.4mA with fully-charged cells,
this ~1mW total draw from the battery of ~10Wh capacity,
(much less than 1000th of my previous solution!)
thus nominally good for the entire winter at 10 hours per day before recharge,
though self-discharge from the batteries is probably higher.
The resistor value can be reduced to 100Ω or thereabouts
to increase brightness at the cost of reduced battery life.
(We can recharge those cells from solar or the mains.)
Adding a SPU30P06P P-channel power MOSFET (that I had to hand) and
a SFH300-3 phototransistor gate to source with a 1MΩ pull-down resistor
gives me a nightlight that goes off automatically in the light.
(I've done this mainly to make the batteries last longer between charges,
maybe a month, and because I can...)
The small capacitor is to try to suppress any tendency to oscillate.
(As of the start of March 2011 this is still going strong on the battery charge
in mid-December! I gave it a recharge from my off-grid system on the evening
of 8th March with the battery voltage at 4.52V... As of 10th September the
batteries were still reading over 5V in daytime, ie with the LED off;
so I charged them the next day as a dump load from my full on-grid batteries,
reading 5.6V fresh out of the fast-charger!)
As a variation on the theme I can report that 3 x white LED (nominal 7cd)
in series with 1kΩ works well from a 12V nominal supply too.
(Maplin part N21BY, 3.2V fwd, 5mm white, 7cd @ 20mA.)
Steve C wrote to tell me about the motion-triggered Philips SpotOn LED
that uses AAA batteries (ie that could be rechargable)
"We've got 3 of them at floor level and they
work very well, particularly with the motion sensing mechanism meaning
they only switch on when they detect your presence and then switch off 30
seconds later."
12V DC Solar Power
The reason that I've taken a special interest in LED lighting is because I was
looking for efficient low-voltage lighting for my solar power PV project,
mainly for a decent desk lamp replacement. The initial light for this project
was a 16W caravan-style CFL, which is a little bit flickery and blue for my
liking, and which produces noticable heat from its built-in inverter.
The initial LED lighting that I supplemented this with was a
3W 180° floodlight white LED
meant for car 'modding' fancy lighting effects. It is tiny, but mounted behind
my shoulder sheds a noticable light that fills in many dark corners and avoids
the feeling of sitting in a candle-lit cave!
As of 2009 on 12V I had both 3W 'cool' MR16 and 9W 'warm' bulkhead LED lamps.
At the turn of 2010, with my ~4W server soaking up the off-grid juice 24x7,
I reverted to a mains 'EQ60' ~7.5W LED lamp most of the time,
but with more sunshine around out of winter
I expect to use the 12V devices more to soak up 'excess' off-grid energy.
Cautionary Tale from Yesteryear
A real-life story from 2005 as related by a friend:
An electrician I know was working on a huge house in [the UK]
and building control wanted to see x percent of low energy lamps as required by
law. The owner then decided to replace all the lamps in the house with LED
ones. Apparently it looked good.
For me the problem with them is that the light seems bright, but the light that
falls on the surface isn't as bright as you think it is. One of the local
wholesalers has a demo of various lighting methods, and they have LED
downlighters alongside conventional GU10 lamps. The LED looks bright in
comparison to GU10, but the light at the source just isn't.
Captain's Log
Update 2007/09/23:
I stopped using the 3W LED 'car modding' light as backlighting some time ago,
as my warm-white 13W CFL is very comfortable to work by.
However, today I noticed that my local lighting shop had in stock on the shelf
a 3W white LED MR16 spotlight/lamp and the base to plug it into.
I was curious to try the MR16 format, since it seems to be very popular.
The light (6000K) quality/colour is OK, though seems to be the same
yellow-phosphor-over-blue-LED construction that we don't much like
in our kitchen 5W LED spot. This doesn't feel as watery and weak somehow.
(November 2009: we rearranged our kitchen lighting a little,
and using the 5W LED as a spot for our blue countertops works well.)
It does not not seem to provide enough general illumination to work by
(ie the lighting angle/cone is very narrow) but in a pinch might do
if for some reason I find myself very short of power or the CFL breaks!
(On further fiddling to set it up as an indirect uplighter,
I think this could just about do as a work light, as I'm using it right now.)
Update 2007/11/07:
I have been using the 3W LED MR16 as an uplighter most of the time over the
last month or so, particularly later in the evening. Earlier, when the sun has
just gone done, I prefer the brighter CFL sometimes. But note that I'm still
entirely on solar PV powered lighting, and have not once yet run out of juice!
Update 2008/02/17:
I am still mainly using the 3W LED as I have since November,
but there are times such as this evening when I go hog wild and use the CFL
instead!
Update 2008/08/23:
Yesterday I ordered from UltraLEDs one of these warm-white (3500K) 9W 500lm LED dome lamps and added to my RE system. It arrived today: very good service!
The dome's light intensity and colour is very close to that of
a similar wattage 'warm' (mains) CFL that I have in the same room,
and should be a little less depressing to work by on a cold winter's evening
than the cool-white...
Having both the dome and the spot on at once is pleasing too.
The 9W dome light cost £40 (~USD80)
whereas a similar-rating CFL might cost 1/10th of that,
so the technology is here but the price needs a little work for prime-time...
Update 2010/01/11:
Thurmond in Texas very kindly sent me an assortment of power LEDs to play with!
The very first thing I did was replace the incandescent bulb in my daughter's
2-cell (NiMH rechargeables) torch with one of the pieces Thurmond provided,
and it gives a much brighter (and bluer) light and should proably last longer.
Even better, those cells were charged in the summer from our PV I believe...
(Just noticed in an ad the EQ60 60W replacement bulbs from Light Planet which is 7W/560lm, which is on a par with CFL if so, and these claim to be the same shape and size as an incandescent and at ~£15 could be a very good deal. I had a chat with Light Planet and I am buying one and borrowing another for eval for this page.)
Update 2010/01/14:
The lights turned up today.
Although the specs on the box are more modest than described on the phone to me
(though this is from a pre-production sample/test batch),
the ~7W ES27 (Edison Screw) spotlight is brighter
and gives off significantly less heat than the
(slightly aged) 12W "softone" CFLs next to it and is a really nice light,
and is small (hardly anything will actually physically fit in that socket).
If what's on the box is right then it's 7.5W/450lm (Cree LEDs),
which is the same efficiency as a typical CFL.
(Here is a US review of the same bulb.)
The cool/daylight version is 560lm it seems, so ~20% more photons for the buck.
The box brand is 'tess' (from Taiwan), part T-67004, 200V-240V AC 50/60Hz,
colour temperature 2700K ("warm white"), weight 125g, 108mm x 60mm, E27.
I need to measure actual power consumption.
Update 2010/01/15:
Swapped in the 7W/355lm "warm white" (2850K--3000K), CRI 70, 120° beam angle
Aeon (Taiwan) ALTLED Aurora V3 M02GW007KC-90, -20°C--40°C ambient,
100V-240V AC, 50/60Hz GU10 spot/downlighter
for my daughter's current bedside 3W 6000K LED,
and it is as expected much brighter and warmer.
It also looks a little more delicate (more fins at the front)
and interestingly takes something like a second to switch on,
and quite a few seconds to completely fade to off.
(A quick test of the ES bulb in my desk reading lamp
replacing a new 12W "softone" CFL seems satisfactory too, this evening.)
Update 2010/01/16:
These new lights are going down well:
we may well buy another couple of the EQ60s to replace failing or dead CFLs
since we like the (warm) colour and haven't noticed any (eg RFI) problems...
My power meter claims that the EQ60 draws 7.7W with a 0.45 power factor.
Update 2010/02/01:
Waiting for 'production run' EQ60s warm and cool white for eval.
Today bought 2W 'warm' Philips "AccentWhite" candle ES14 bulb for
younger child's room as reading lamp for ~£9.
Update 2010/03/10:
Received 'production' EQ60s. No power measurements yet taken.
Due to a mix-up a cool bayonet was sent instead of warm,
along with the requested cool ES27 screw model,
which feels a little harsh/clinical for some of the possible settings.
The amount of light is astonishing and feels comparable to a 20W warm CFL,
and knocks the socks off, for example, a 9W warm CFL I replaced in one location.
Also, I was concerned that even the 120° beam would be too narrow
for normal (eg non-spot/anglepoise) fittings,
but though the colour didn't immediately appeal,
the light spread seems entirely as good as for spiral/globe CFLs
in the places I've so far tried these EQ60s.
Will try these out in other settings and with other people over the next week.
Update 2010/03/14:
One relative who felt that her 'too yellow' (20W) CFLs were inducing headaches
nonetheless did not like the 7W 'cool' LED as too dim and too 'harsh'.
Update 2010/03/19:
One of the first highish-powered domestic LED bulbs (5W Edison screw)
that we have been testing failed after a little over 2 years' use.
Ultraleds (and their MD) with who I had previously been impressed
were dismissive about my suggestion that devices sold in part
on a promise of long life should be considered "not fit for purpose"
if they fail this quickly, regardless of nominal warranty period.
Update 2010/03/21:
Measured consumption of EQ60 "cool" ES27 bulb at 7.1W--7.8W, power factor 0.57,
better than the pre-production sample values (~7.7W with pf 0.45).
Consumption starts at 7.1W and varied a little going as high as 7.8W.
I think that if this is drawing 7.5W or above on average
it should be rated 8W on the box;
the '2W' Philips "AccentWhite" seems to actually draw 1.6W for example.
It is good that the power factor is increasing/improving;
that could ultimately result in less wasted energy upstream on the grid.
Update 2010/09/16:
Aurora "V5" 7W 720lm "cool" GU10 evaluation unit arrived from Light Planet
(thank you!).
Has a 4-chip array internally. Should match/beat 40W of halogen GU10
or about 12W of a good CFL in light output, and is more efficient than CFL.
Update 2011/09/22:
I couldn't resist the urge to tinker, and given that the batteries
habe lasted 6 months or more in summer, I want to see if I can make
the night-light completely free-standing, scavenging the small amount of light
energy where it is. To this end I have bought (from Active Robots Ltd)
a small PV panel, nominal 6V/200mW, Voc~8V, 37mmx66mm polycrystaline
(part SCC3766-MSE). I shall connect it to the batteries via a diode and
a 470Ω resistor (to limit maximum charge current in bright sunlight to
about 6mA or a 0.0033C trickle charge limit as suggested on Wikipedia).
Inside, even mid-day, I cannot expect energy capture above ~1% of nominal,
so in particular I'll use a low-leakage diode to minimise drain
from the battery back to the panel. Given a lamp draw ~1mW and the PV output
possibly similar for maybe 8h/day each, with the PV output improved
if we can pop the box on a window-ledge when the light gets too dim at night,
this might just work, else I can upgrade to the relatively-huge 1W PV!
Update 2011/09/25:
As a further cheat/enhancement I'm swapping the ordinary NiHM
cells for 'hybrid' versions of similar capacity that should have lower leakage,
ie self-discharge, and thus eke out some extra life in winter. The new cells
are 2100mAh nominal compared to the 2500mAh of the previous ones.
Update 2011/10/17:
Voc of the solar cell/PV in the sort of lighting I'm anticipating is ~2.5V
compared to the battery still over 5V, so to get any useful charging
I suspect that I'll have to buy a second panel and put it in series.
