I see I can now buy a 60W equivalent LED light bulb Philips myAmbiance
872790091840300 at a price which will take the best part of £40.00!Are they any good?
I have also seen LED car stop & tail bulbs. Should I get one the next time a bulb fails?
Check if they carry the E mark - as all suitable replacements must do to meet the regs. You'll likely find they don't.
I would start with a very large dose of scepticism, based on past experience of Philips (and others) claims for performance of new lamp technologies.
I wouldn't spend £40 to find out, but if someone gave me one, I'd certainly kick the tyres. The datasheet shows how much better it is than a 60W filament lamp, but it's got to be very significantly better than a £2 15W CFL before it's viable in my eyes, and it isn't. When it costs a quarter of the current price, I would buy one to try.
Being dimmable is interesting, but most light dimmers won't work with such a low load, so that's probably not useful unless you have lots of them.
Only if the car manufacturer states they still meet the regs, which they almost certainly will not unless they're original equipment.
I read recently that LEDs in cars are not as efficient as touted, it seems they need cooling to work efficiently, so that may apply to the home as well.
The benefits of LEDs on vehicles are the long life and resistance to vibration. They also normally fail in a manner that leaves at least some light being generated by the unit, which is safer than the all or nothing when a filament lamp fails.
The efficiency savings for mobile use aren't worth bothering about except for applications like battery powered cycle lights or torches, as the power used by the lighting on a car is a small percentage of the total power used to move it. At 30mph on a flat road, the absolute maximum total lighting load on most cars, including headlamps and foglamps, is less than 400 watts, as against ten kilowatts or more being used to overcome rolling and air resistance.
LEDS in fixed installations are noticeably more efficient than filament bulbs, as they use a switched mode supply, with a total comsumption of about 10% or 15% that of the filament bulbs for the same light output.
Indeed it does. The lighting industry got a very bad reputation with the dishonest claims for CFLs, and LEDs started off even worse, e.g. quoting efficiencies with the LED chip at 25C, which is only going to apply if you run the thing in your freezer.
Also, faster 'ON' time, particularly for brake lights.
However, the lamp cluster needs to have been designed for LEDs. Retrofitting them into a cluster designed for a filament light source isn't going to conform to regs.
LEDs at that efficiency do exist, but are pricy. Most of the LEDs you'll see at halfway affordable prices are around the same efficieny as CFLs, and the cheaper ones are nearer the efficiency of LV halogens.
Cars use SMPS too for LEDs.
A difference is that 12v tungsten are already more efficient than mains ones.
I'd love to see *any* LED with the same light output as halogen mains. And by that I mean a near 360 degree output of the same colour spectrum. Not just measured by pointing some crude light meter at it. And using the very worst possible tungsten as the comparison.
Sorry, but while you might get 25°F in your freezer, 25°C is a slightly warm ambient temperature.
If that 400W could be reduced to 100W there would be worthwhile fuel savings.
Bill
Less than 3% at constant speed in town, less at higher speeds or when accelerating. Stopping at one red traffic light in a five mile journey would make more difference. Correcting the tyre pressures every time the load changes can make more difference. Removing the toolbox or shopping from the boot makes almost as much difference. The absolute maximum on my car is 210W, and that's using high beam headights and rear fog lights while I'm signalling a turn.
To get the maximum lighting load down to 100W, you'd need to replace the headlights with ultra efficient lights, which at the moment isn't practical. In town, using dipped beams, the load is more like 150W, anyway. You'll only use 400W in a situation where you are driving in foggy conditions or using four high power halogen main beam lights.
Thats the Temperature Junction, Tj, in the data sheets, which is actually a tiny area less than 1mm ^2 heating rapidly as soon as energised.
Astounding effiency can be demonstrated by a couple of difficult to replicate outside of the lab ,er, strategies.
Measure the output in first few miliseconds of start up with a boosted current.
Actively chill the heatsink, to get Tj to 25C means heatsink is going to have to start colder.
Run the device at a tiny current lowering self heating effects then supply the numbers for massage to marketing department....
Cheers Adam
How can foggy conditions result in so much more load? A pair of front foglamps will be the same power as a pair of dipped headlamps and the rear foglamps will only add 21w each which will only push it up to about 200w total
You've got 200W minimum at the front, due to the dipped headlamps *and* foglamps being on, then add the 42W drawn by the high intensity rear lamps, plus at least 42W for brake lights and the same for indicators, when they're being used. Plus, of course, at least 24W for side and tail lights, not forgetting the side marker lights fitted to some cars. I was giving maximum loads, not average ones.
Four bright halogen main beam lights are 350W just on their own.
It would, but that 400w includes headlights. And very few cars have LED ones. HID are more common - and vastly more efficient than tungsten. My 35 watt units produce much more light than 55w halogen. I'm not sure how LED compares to that.
It already is. HID are commonly 35 watts per lamp. And produce far more light than 55w halogen.
The top-end Audis have optional LED headlights, it mentions 40W per unit for the dipped beam, but doesn't state the wattage for high-beam.
There is absolutely no point in using both in fog. The idea of low mounted fog lights is they cut beneath the fog and light the road. Headlights as well will just produce scatter and blind you.
That's more or less the same as HID. Be interesting to do a comparison. I'm very happy with my HID units.
The only snags with HID is the time they take to reach full brightness, and not being a good idea to flash them, like all such types. Not a problem in practice, but means you can't switch them on and off like 'normal' units. So you either use mirrors for dip/main beam or add conventional mains. And some other lamps for flashing.
I suspect LED will prove cheaper, rather than better, in the scheme of things.
The original "aim" was to pick out the kerb with the left one, and the lane marking with the right one, nearer to the car than the dip beam headlamps will effectively light. Nowadays, they're rather more cosmetic than functional, and often can't even be adjusted to aim/cutoff correctly.
Can do, depending on conditions, but not always.
All proper fog lights have a wide beam with a sharp cutoff. So can't really be aimed as you suggest.
Some cars have extra driving lights rather than true fogs. As you say more to differentiate the head of paper clips car from his mere salesmen.
Always. That's why foglights are low mounted and illegal in good visibility. If the headlights were good in fog - why have specialised lighting just for it?
But I'm talking about proper fog where you're reduced to walking pace.
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