The flaw in the argument about energy use rising due to decreased efficiency is that it assumes that the user will compensate for the lower light level by turning on additional illumination. Whereas in reality they will probably just "put up" with less light until they get so fed up and fit "a bigger bulb".
Yup, that is pretty much the point I was making. If you are going to claim something will last n years, then you need to state the bases if that claim - i.e. do you really mean n years of 24/7, or more likely n years of "typical use" for some value of typical. If you want the x hours per day thing to form a hard limit that is a condition of the warranty, then you had better explain that explicitly.
I also have my doubts about the capacitors used in the PSUs in many of these lamps actually lasting anything like as long as the lamp.
I suppose if you average out the yearly use for a family at work during the day and only using a lamp in the evening, it might be slightly plausible - still seems a bit short though even then.
I'm applying "The Osbourne Effect" in spades. I'm also doing my best to educate the public at large with regard to the empty promises made by Philips Lighting and Cree just over 2 1/2 years ago when they both announced their latest laboratory achievements of 280[1] and 303 Lumens per watt LED lamps respectively.
I'd be more accepting of the delay in fulfilling these promises if some sort of steady progress in improving lamp efficiencies was being demonstrated in the supply chain but so far, over the past 3 years, we seem to have been stuck with lamps in the 81 to 90 Lumens per watt efficiency range. Where are all those 120 to 150 Lm/w lamps that we might have reasonably expected to be made available by now?
It would seem that Cree and its customers are in some sort of Mexican stand off, each waiting for the other to blink before making their next move, quite possibly because their main competitor, Philips Lighting, have dropped out of the game leaving them with a near monopoly situation they're doing their best to exploit whilst they still can. Who knows? I'm just taking my best guess as why further development in LED lamp technology efficiency has remained stalled at the 81 to 90 Lm/w mark these past 3 years or so.
[1] I can't find the original news announcement made by Philips Lighting so the 280Lm/w figure is my best recollection of their 'record breaking' lamp performance figure. I may be wrong but I do know they were trumped by Cree's "record breaking" 303Lm/w lamp announcement at just about the same time.
It's always possible that Phillips are using these high output LEDs in their theatric division rather then their domestic one. In that areea forced cooling, by means of a fan, isn't uncommon.
Points 1, 2 and 4 are important to me. I'm not really concerned by their dimmability (this just adds to the cost of the lamp for a feature I'm unlikely to utilise).
The main benefit at *this* stage of the game with item 4 is the reduced running temperature of say a 10W 1620Lm LED compared to a 10 watt 810Lm LED (same power consumption but less being dissipated as waste heat). This means the more efficient LED lamps can be fitted into "LED unfriendly" GLS luminaries where the extra light output is needed to replace that of a 100 or 150 watt tungsten filament lamp.
I too take a pragmatic view of the situation, having invested a whole 13 quid in those 5W LED SES candle lamps on sale in Poundland (or Poundworld) to replace the 7 and 8 watt CFLs (two wall lights and a couple of 5 lamp chandeliers and a spare lamp) a few weeks ago. One of them failed after about a week, hence the purchase of the extra as a spare when I returned the faulty one for exchange.
I'm holding back on buying high output LED lamps mainly on account of their excessive price points and the fact that they may not survive very long in the existing fittings where I'd like more light. I've still got a now dwindling stock of CFLs to replace any of the existing fleet I've got installed.
The only GLS incandescent lamps we have left in service now are the 100W ES in the bathroom ceiling luminary and the four 35W 12v halogen downlighter lamps fitted in the shower room which have all survived the past 5 or 6 years since they were first installed. Both areas in the house with a low occupancy factor and therefore the lowest priority with regard to a lighting upgrade to more efficient lamps.
"Luminary" is just the 'posh' or 'technical' term for any light fitting, commonly used by the authors of technical publications relating to lamps and lighting. I presume you're referring to a pendant lamp holder hanging from a ceiling rose cord (naked or else fitted with a well ventilated lamp shade of some sort).
If that presumption on my part is justified and you're considering this aspect of lamp usage on every occasion where you decide to fit a LED lamp to replace a tungsten filament GLS lamp (or even a CFL), then you're doing exactly the right thing.
Lamp holder or light fitting (or Luminary) wattage ratings were more about how much heat they could cope with from an incandescent lamp than about the lamp itself. With LED lamps, the wattage limit is a function of how well a luminary can keep a LED lamp cool enough to achieve its rated life (typically 15 to 30 thousand hours with the higher wattage examples). There is no easy rule of thumb over de-rating a 60W fitting down to say 20 or 25% when used with a LED lamp. Although such a de- rating figure is a handy starting point, you still have to consider how well the luminary is likely to perform in preventing unwanted heat build up.
The higher the LED lamp efficiency, the less of an issue such heat build up becomes. When I invested a fiver in an Asda 5W 270Lm 'bargain lamp' 5 or 6 years ago, I'd intended it for the wall mounted bed head luminaries to replace the overly bright 7W CFLs which had replaced the 25W tungsten filament BC22 candle lamps originally fitted.
These luminaries used small "Snowdrop" style glass shades which offered no through ventilation. Not a problem for the incandescent lamps they'd been designed for (and not much of a problem for the 7W CFLs since they protruded further out of the open end of the glass shade). However, I realised that my 5 quid investment could land up cooking itself to an early demise from the effect of inadequate ventilation.
Indeed, I got the impression (rightly or wrongly) that the light output was reduced after being lit for more than 15 to 20 minutes suggesting that the LEDs were operating uncomfortably close to their upper temperature limit. Discretion being the better part of valour, I landed up relegating this "Asda Special" to a ceiling mounted batten socket at the foot of our basement stairs where it has been in service ever since without (as one might expect of an open unshaded lamp holder in a lower than usual temperature environment) any signs of impending failure.
A couple of months ago, I spotted 5W 325Lm BC22 candle lamps in Poundland and decided it was worth a punt to trial one in one of those bedroom wall light fittings. The results, compared to the more expensive 270Lm "Asda Bargain", were a lot more encouraging so I bought a second lamp to complete the upgrade.
After a few weeks of trouble free service, I felt confident enough to invest another 7 quid on SES versions to upgrade the lighting in the living room (2 wall luminaries and a 5 lamp chandelier), followed a fortnight later with an upgrade to the similar 5 lamp chandelier in the lounge which, after about a week or two's service, suffered a lamp failure.
One random infant mortality failure out of 14 LED lamps bought in our local "Pound Shop" seemed pretty good going imo, especially since you never get any arguments when returning faulty items for refund or replacement in the Poundland or Poundworld stores.
In terms of appearance, apart from the "whiter light", they perform just as well as the traditional pearl enveloped tungsten filament lamps they've replaced. With a 15,000 hour rating, these lamps would seem to be much better value for their money than a traditional tungsten filament lamp costing around 25 to 33 pence each when bought in packs of 4 or 3 in a pound shop.
Of course, only time will tell whether the promised 15,000 hour average lifetime is a realisable target or simply just 'hype'. Where they've been installed in low usage locations (bedroom reading lamps or the very rarely used 5 lamp chandelier in the living room and that basement location) it could quite easily take several years of use before they've even clocked up their first thousand hour's worth of run time.
The living room wall lights are the most likely to give any indication of actual versus promised life time performance figures over a reasonable timescale. At just a pound each lamp, that's not too great an investment to run 'The Experiment' to prove or disprove the life time rating claims made for these lamps.
Morrisons are selling LED lamps that appear to have come off the same factory production line as the Poundland ones but at just over 4 times the price! I think it is a similar story in Asda, Aldi and Lidl stores. Just for once, it seems Poundland are offering a product at a genuinely bargain price. They say you get what you pay for but I'd be very surprised if this turned out to be the case for those Poundland lamps.
If the "Famous Clive" can be persuaded to sample such lamps from Poundland and Morrisons, et all for a really in depth analysis (usually to the point of destruction), we'd all be guaranteed a definitive answer. :-) It might be worth checking out his more recent YT videos for such a product comparison. You never know, he may already have done the work for us.
or any other holder. Some use the term voltage to describe somnething whereas here we can also use the term potentail differnce, but go into shop and ask for a battery of 9V potentail difference.
yeah sorted.
Well normally the heat comes from what's plugged into it. At thier base LEDs lamps/bulbs (rather than LEDs) get hot to the touch. very hot in fact.
My LEDs lamps and bulbs are mostly used with dimmers (trailing edge) they are usualy dimmered by at least 50% ('measured by rotation of the pot) I believe this may help with reducing teh heat they do produce.
you devil :)
I'm replacing the majority of my none LEDs light with LEDs as the tungsten and halagen blow.
It does.
I've never tried I aviod these places I only have an hour lunch break
Is there any info on how long they can be kept on for ?
Where they've been
true if age is the only critria for them blowing.
I'd like to see you're 'blind' study :)
if I had teh space and time I;d put one on and leave it on 24/7/365.
and another I'd leave on for 12 hours a day, both should last the same lenght of time when on. So the 12 hour day one should last twice as long as the 24 hour a day one.
You can get a slap if you say that to the wrong person
but I'd be very
I did watch one but he said the 'bulbs' are no longer avaible in teh UK.
I doubt his had a LED's lamp or bulb on for teh bpast 5-15 years His don't last much longer than his videos ;-)
Thank you TNP. I'd just got to the point where I couldn't stand the thought of yet more dignitaries around my house just hold lamps, so you saved me from pointing out the difference.
Unfortunately the LED bulbs sold in pound shops or even a well known food outlet are likely to be a different manufacturer next week. 'Branded' LEDs are likely to be more consistent in their performance BUT they will be a lot more expensive and may not perform any better than the best of the pound offerings.
My experience with LEDs is that 5/6 years ago many led bulbs I purchased failed - mainly getting much dimmer. In the past 2/3 years LEDs I've purchased (branded and cheap non-branded) have been very reliable. However I now only have 4 bulbs in fittings with restricted ventilation. I have replaced 4 fittings with panel type LED lights and other LED bulbs are in fairly open fittings.
Actually, not necessarily 'famous' so much as a person held up by their peers as "A Leading Light" in their field of study or expertise.
I checked this out a few months ago because that was also my recollection (I just wanted to be sure of the spelling). However, I seem to have gotten turned around to the use of "Luminary" for some inexplicable reason (possibly a case of 'over-thinking it' and the 'double bluff' effect coming into play. :-(
Anyhow, wherever I've used the word 'luminary' in the context of lamps and lighting, I've obviously intended the word 'luminaire'. My apologies for the irritation this must cause (on a par with misuse of the apostrophe, confusing 'to' with 'too', 'loose' with 'lose', 'may be' for 'maybe' (and vice versa) and many more such faux pas too numerous to mention in a usenet posting).
My apologies btw, for misusing 'luminary' in place of 'luminaire' (which I've just added to Pan's spell check dictionary).
That's very much affected by lamp orientation since most of the heat is generated by the LEDs themselves. fitting a LED or CFL type of GLS lamp 'cap up' as in a typical pendant fitting will cause the cap to run hotter simply because the half to one watt dissipation by the electronic ballast components become reliant upon the warm air being convected from the envelope to keep it cooled. The modest heat dissipation in the cap or base of the lamp just raises the cap temperature until a new thermal equilibrium is attained.
For a high quality lamp with a high efficiency electronic ballast using high temperature long life components, this could well be the optimum orientation despite reliance on a flow of warm to hot air to carry away the heat produced by the losses in the ballast components. The key thing here is to provide ample ventilation around the lamp. The less obstructed and faster the flow, the lower its temperature will be and the more effective it becomes (even at elevated temperatures) as a means of cooling the lamp components due to the higher velocity of that airflow.
Unlike that 30W CFL, there's no mention of such a caveat in relation to a warranty. In fact, there's no warranty period mentioned at all other than the 15000 hours average lifetime and a switching cycles rating of
10000 times along with a promise to replace or refund if not satisfied with the lamp's quality along with the caveat "This does not affect your statutory rights." The packaging shows the brand name as "Electrek" with a UK address (post box number in the Birmingham post code area). Undoubtedly, this is an import company rather than an actual manufacturer (unless they're claiming to be a manufacturer which just happens to outsource every aspect of production to other more specialised manufacturers).
That 2.7 hours a day caveat on the 6 year warranty with that 6000hour rated 30W CFL I mentioned earlier, was simply to indicate that even in very low usage cases, it would be covered by that untypically extended warranty.
I'd rather doubt I'd be around long enough to see the end of such a study. Life's just too short for that sort of indulgence. :-(
Unless they incorporate a suicide countdown timer circuit, you'd probably have to use ten times as many lamps to get a more meaningful statistical finding.
If you're going to go to that much trouble, you might as well take measurements of their light output on a regular basis, say every 500 hours of run time, whilst you're at it (and, for completeness, measure their operating temperatures against room temperature). :-)
Ah well, he does seem to insist on testing these things to destruction so that's just to be expected. :-)
I rather like his "scientific" approach to analysing such product. When you think about it, he's using exactly the same approach as the physicists working with the LHC at CERN. I don't suppose you could get much more 'scientific' than that. :-)
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