kermit_rr said:
a good read on the different colour temps
suparee.com

Best LED Headlight Color Temperature for Night Driving: 4300K vs. 5800K vs. 6500K

When it comes to upgrading your vehicle's headlights, LED technology has revolutionized the market, offering superior illumination, energy efficiency, and longevity compared to traditional halogen bulbs. However, with the various color temperature options available, such as 4300K, 5800K, and...
suparee.com suparee.com
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Longevity? Not likely with LED's, they will not match the life of the tungsten bulbs in my P38 which are 25 years old or the ones in my MR2 which are 38 years old.
 
Datatek said:
Longevity? Not likely with LED's, they will not match the life of the tungsten bulbs in my P38 which are 25 years old or the ones in my MR2 which are 38 years old.
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does depend if they are cheap over-driven units.. which most available in EU are, at least for residential use
 
Datatek said:
Longevity? Not likely with LED's, they will not match the life of the tungsten bulbs in my P38 which are 25 years old or the ones in my MR2 which are 38 years old.
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Actually, LED's will last longer than the tungsten or tungsten-halogen equivalent in the same vehicle as they don't suffer from increased filament shedding due to raised system voltage. Other variables are of course vibration and the percentage of use per time period. As mentioned above (and also relevant to filament lamps) the initial quality has a large bearing upon longevity.
 
Graculus said:
Actually, LED's will last longer than the tungsten or tungsten-halogen equivalent in the same vehicle as they don't suffer from increased filament shedding due to raised system voltage. Other variables are of course vibration and the percentage of use per time period. As mentioned above (and also relevant to filament lamps) the initial quality has a large bearing upon longevity.
Click to expand...
Not in my experience. Light output also degrades over time.
 
Datatek said:
Not in my experience. Light output also degrades over time.
Click to expand...
We have different experiences of the same thing then. 'Xenon' lighting does indeed over time but I've not seen any cases of LED lighting - certainly not 'branded' or OEM LED's degrading in output - unless you mean 'no output at all' which is 100% degraded... In most cases it's caused by collision damage allowing water into the lighting assembly.
Tungsten filament lighting also degrades over time - as I'm sure you know. The tungsten filament 'sheds' particles which end up on the glass envelope, which is the dark coating you get on old filament lamps, often dimming the visible output enough to cause it to be insufficient to pass an MoT test, particularly on 5W sidelights - you'll also notice it on 21W (or 21/5W combination lamps) brake lights where the driver has a habit of holding the car on the brakes excessively.
 
Graculus said:
We have different experiences of the same thing then. 'Xenon' lighting does indeed over time but I've not seen any cases of LED lighting - certainly not 'branded' or OEM LED's degrading in output - unless you mean 'no output at all' which is 100% degraded... In most cases it's caused by collision damage allowing water into the lighting assembly.
Tungsten filament lighting also degrades over time - as I'm sure you know. The tungsten filament 'sheds' particles which end up on the glass envelope, which is the dark coating you get on old filament lamps, often dimming the visible output enough to cause it to be insufficient to pass an MoT test, particularly on 5W sidelights - you'll also notice it on 21W (or 21/5W combination lamps) brake lights where the driver has a habit of holding the car on the brakes excessively.
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Started out life as a normal 21w bulb
PXL_20241029_182544141.jpg
 
Graculus said:
We have different experiences of the same thing then. 'Xenon' lighting does indeed over time but I've not seen any cases of LED lighting - certainly not 'branded' or OEM LED's degrading in output - unless you mean 'no output at all' which is 100% degraded... In most cases it's caused by collision damage allowing water into the lighting assembly.
Tungsten filament lighting also degrades over time - as I'm sure you know. The tungsten filament 'sheds' particles which end up on the glass envelope, which is the dark coating you get on old filament lamps, often dimming the visible output enough to cause it to be insufficient to pass an MoT test, particularly on 5W sidelights - you'll also notice it on 21W (or 21/5W combination lamps) brake lights where the driver has a habit of holding the car on the brakes excessively.
Click to expand...
On the ones I have looked at, the high brightness is obtained by pulsing the Led's with a duty cycle of around 50% which allows the LED's to be run at higher voltage with cooling in the off period. Mostly it is the electronics that fail. LED lights age over time and progressively get dimmer until they stop working altogether. This is what we call “lumen degradation” or “LED degradation”
 
Mark Piercy said:
You are😜
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Not with one of these!

It's in the car on a 12V charger, we're on a 'bleep list' for missing dogs (and occasionally people) as we used to have an ex.- MWD trained in combat search & rescue that was exceptionally good at tracking missing dogs across all types of terrain and would often find them and comfort them until we arrived. We no longer have that dog but we still help out with area searches when needed.
 
Datatek said:
On the ones I have looked at, the high brightness is obtained by pulsing the Led's with a duty cycle of around 50% which allows the LED's to be run at higher voltage with cooling in the off period. Mostly it is the electronics that fail. LED lights age over time and progressively get dimmer until they stop working altogether. This is what we call “lumen degradation” or “LED degradation”
Click to expand...
As above, overdriven LED's will have a shorter life and age quicker, but the ageing phenomenon isn't as marked as you'd have us think - the first link when searching for 'LED degredation' is this one, which suggests, all things being equal, that it's pretty much a non-issue. https://lamphq.com/led-degradation/ Of course, the 'buy cheap, buy twice' LED's will have more issues with control electronics, that's not the sort of equipment I work with or buy for myself though - possibly why LED degradation isn't a factor I've ever had to learn about or be troubled with.
 
Graculus said:
As above, overdriven LED's will have a shorter life and age quicker, but the ageing phenomenon isn't as marked as you'd have us think - the first link when searching for 'LED degredation' is this one, which suggests, all things being equal, that it's pretty much a non-issue. https://lamphq.com/led-degradation/ Of course, the 'buy cheap, buy twice' LED's will have more issues with control electronics, that's not the sort of equipment I work with or buy for myself though - possibly why LED degradation isn't a factor I've ever had to learn about or be troubled with.
Click to expand...
As I said all LED's degrade over time, I did not specify a time scale. In most cases it's the electronics that fail rather than the many individual LED's that make up the lamp.
From your link:- After purchasing an LED lamp usually has the brightness specified by the manufacturer. Over time, the luminosity slowly decreases and the lamp becomes darker. By the way, this effect also occurs with old incandescent and halogen lamps and especially with energy-saving lamps.
after just a few thousand hours. At the end of the life expectancy the filament breaks and the lamp remains dark. Such a sudden defect cannot occur with LEDs. This is pure marketing bull****, LED lamps can and do fail instantly, as I said due to failure of the electronics.
 
What I've seen.. i presume it's cheap electronics on overdriven units.. they can go 1/3-1/2 brightness, again.. presume part of the circuit dies rather than the LEDs
 
Datatek said:
As I said all LED's degrade over time, I did not specify a time scale. In most cases it's the electronics that fail rather than the many individual LED's that make up the lamp.
From your link:- After purchasing an LED lamp usually has the brightness specified by the manufacturer. Over time, the luminosity slowly decreases and the lamp becomes darker. By the way, this effect also occurs with old incandescent and halogen lamps and especially with energy-saving lamps.
after just a few thousand hours. At the end of the life expectancy the filament breaks and the lamp remains dark. Such a sudden defect cannot occur with LEDs. This is pure marketing bull****, LED lamps can and do fail instantly, as I said due to failure of the electronics.
Click to expand...
Of course.
Enjoy your night!.
 
AndyF07 said:
Well today started stripping down my lovely 2002 4.0 P38 to replace the head gasket due to a small oil leak. After 165k miles a bit of tic that is well deserved. Bad light stopped play for today (shame the clocks went back) but think I found the leak :):) Upwards and onward tomorrow.....
View attachment 329075
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Having done similar on Otto the first year we had him, can recommend green gunk or autoglym engine and parts cleaner, effective and much less toxic. Also replacing head bolts with a stud kit, torque to 25lbft, leave overnight, torque to 50lbft, can then go straight to 70, no detectable extra movement over 50. No stress about angles or stripping threads.
 
Scotiawhiskers said:
Having done similar on Otto the first year we had him, can recommend green gunk or autoglym engine and parts cleaner, effective and much less toxic. Also replacing head bolts with a stud kit, torque to 25lbft, leave overnight, torque to 50lbft, can then go straight to 70, no detectable extra movement over 50. No stress about angles or stripping threads.
Click to expand...
Cheers @Scotiawhiskers. Great minds think alike ... have already got a stud kit as seems so much easier :) I will look into the degreaser, thank you for the recommendation.
 
Not done anything to the 38 today except pick up a windscreen crack from something hitting it on a dual carriage way this morning. Insurance excess of £115 and autoglass coming to replace next Tuesday at home. I prefer home as I can strip the bits off myself so the guy or gal can just do the glass, I'll reassemble too afterwards. Everything is online which is a little concerning as there was no box to tick for heated screen, just for tint and my reg . Can't find anyway to contact a human to confirm if they are supplying a heated screen or not. Could be a wasted journey for them and unnecessary stripping for me...
 
When i had the screen done in my p38 they refused to do it at home -too heavy.
Went to Shrewsbury and they fitted a screen that was damaged. Had to go back again for a second screen.
When i needed a new screen on this l322 they fitted 3 screens over about 14 months FFS
 
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