General > General Technical Chat
The Dubai Lamp
Twoflower:
--- Quote from: MK14 on April 09, 2022, 07:13:15 pm ---They seem to be available for sale in the UK, e.g. John Lewis. But are rather pricey at around £12 for the 60 Watt equivalent ones ( https://www.johnlewis.com/philips-60w-e27-led-non-dimmable-classic-bulb-clear/p6040141 ). Also, some express concern it is a 3000K colour temperature, rather than the warm white 2700K ones, that you normally get.
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Wow, here in Germany we can get them for just below 10€ (£8). But still much more expensive compared to the 'normal' Philips bulbs (~3,50€ for 100W).
The 3000K might not be that bad. In the kitchen I have 4200K (with CRI >90) by intent. Direct comparing that to warm white it's a huge difference. But 3000K vs. 2700K might not be that bad. One might say: It depends. Especially where you plan to use it.
MK14:
--- Quote from: Twoflower on April 09, 2022, 07:40:30 pm ---Wow, here in Germany we can get them for just below 10€ (£8). But still much more expensive compared to the 'normal' Philips bulbs (~3,50€ for 100W).
The 3000K might not be that bad. In the kitchen I have 4200K (with CRI >90) by intent. Direct comparing that to warm white it's a huge difference. But 3000K vs. 2700K might not be that bad. One might say: It depends. Especially where you plan to use it.
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That shop (John Lewis), is a large chain of department stores. Which tend to sell expensive items, for middle class people. So, when/if these ultra efficient LEDs are more widely available, the price in the UK (and elsewhere), could easily drop.
I'm unsure if the relatively high price, is because Philips are reluctant to sell LED lights with such long life times, as it could make them lose lots of customers, until the 20, 30 or even 50 years, life time is finished.
But it could be (the high price), because it is rather new to the market, expensive to manufacture (needs lots of LEDs, and possibly high energy efficient LEDs, could be more expensive as well, per individual LED), also some people think they have more expensive controllers and other circuitry, to significantly reduce the power consumption.
Also, it could be because many customers are put off by such big prices. Especially as those potential customers, probably are not concerned by saving a few watts per LED bulb, and believe they wil get the stated 15,000 hours lifetime, from cheap/standard/normal LED bulbs. Hence poor economies of scale, which tends to drive the prices up, compared to popular, mass market items.
I suspect those bulbs really will give close to 50,000 hours life time (because of expected very low operating/running/dissipation temperatures as so efficient and quality design/components), unlike many LED bulbs which claim e.g. 15,000 hours, yet seem to fail after around a year or so. Perhaps 5,000 hours out of the 15,000 hours, at a guess, then they seem to fail. Possibly in my case because the bulbs cooling is hindered (partially enclosed fittings and/or bulbs the wrong way up (pointing up to the ceiling, instead of down towards the ground), which is suppose to mess up the cooling patterns).
If they save perhaps 3 watts, then over 50,000 hours, and at around 30p per kilowatt-hour.
Savings would be around ((3 x 50,000) / 1000) * £0.30 = £45 (spread over the next 20, 30 or even 50 years, lol!).
Also, let's say the cheap bulbs are £2.50 each and ten (50,000 hours / 5,000 hours I approximately get = 10) would have been needed, then it's £12 instead of £2.5 x 10 = £25, which is also a nice saving.
I'd have to compare the 3000K warm light to the standard/usual 2700K warm light, to see if it bothers me or not. But certainly in some areas/rooms, it should be ok anyway, so these are useful things, especially in hard to reach, bulb replacement areas, such as any high up (ladder needing), outside lighting.
Twoflower:
Same here. I think the'll last long time as the design uses rather relaxed constrains. If the last the stated 50.000h depends on many things. Temperature, probably even noise on the supply lines and so on. The stated 50years if you use it 3h/day enters a totally new range of potential failures. Like the glue that was used ages ago that get conductive over time. Or look at the aging effects visible at some of Noopys incredible die pictures.
I just replaced my CFL-bulbs after 15 Years in service. Since many of them showed signs of aging and one died. So the replacement to LED halved the power consumption. Hopefully the LEDs last as long als the CFLs. Chances are good as most of the fixtures are open and just 25W and 40W eq. But I don't think it is worth to change existing, but working LED bulbs.
MK14:
--- Quote from: Twoflower on April 09, 2022, 08:33:57 pm ---Same here. I think the'll last long time as the design uses rather relaxed constrains. If the last the stated 50.000h depends on many things. Temperature, probably even noise on the supply lines and so on. The stated 50years if you use it 3h/day enters a totally new range of potential failures. Like the glue that was used ages ago that get conductive over time. Or look at the aging effects visible at some of Noopys incredible die pictures.
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That's exactly/similar to my experiences. A very long time ago, I had a light which was a bit of a nightmare to replace (outside, needed a ladder, fiddly light fitting, that needed unscrewing and careful disassembly, to avoid dropping its fragile glass part, from the ladder). So, I managed to get these supper long life (tungsten filament) bulbs. I can't remember exactly, but they had a design life of something like 20,000 to 60,000 hours or more (supposedly designed for aircraft or airport use, or similar).
It was around 40 Watts, a bit dim for 40 watts, but perfectly usable (60 watts, if I'm mis-remembering).
Their advert would be too old to find on the internet now, but I found something similar:
--- Quote ---Clear Incandescent Rough Service Light Bulb, 40 Watt, Long Life - 10000 Hours, 2700K Soft White, E26 Medium Base, 260 Lumens
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In my case it said something like, typical life can extend to 35,000 hours or more (from memory).
But to my significant disappointment, after around 2.5 years, the glass cracked (probably due to temperature extremes and changes over time), and the bulb hence broke.
A bit like the glue failure, you mentioned.
50 years is pushing it for many electronic components. Even the lead-free solder joints can break/crack from the temperature changes, during on/off operations, in theory. Like the xbox red ring of death (I think rumored to be the lead-free solder cracking, under the GPU, because of temperature cycling/changes), but used as an analogy to ultra long life LED light bulbs. Capacitors can easily fail, as well as many other components. Resistors can drift in value too much, and so forth.
--- Quote from: Twoflower on April 09, 2022, 08:33:57 pm ---But I don't think it is worth to change existing, but working LED bulbs.
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I've got exactly the same dilemma, and come to a similar conclusion. Wait until the current bulbs burn out and/or stocks of replacements run out, before choosing which ultra efficiency LED bulbs to get. Unless it was the old filament bulbs, which do use relatively huge amounts of power now,compared to modern alternatives.
james_s:
--- Quote from: MK14 on April 09, 2022, 07:59:00 pm ---I'd have to compare the 3000K warm light to the standard/usual 2700K warm light, to see if it bothers me or not. But certainly in some areas/rooms, it should be ok anyway, so these are useful things, especially in hard to reach, bulb replacement areas, such as any high up (ladder needing), outside lighting.
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A lot of halogen bulbs are 3000K and have been for many years. The only time you're likely to notice is if you have a mix of different color temperatures in a room. I've been amazed at how quickly the brain adapts to treat any light source as "white".
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