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Helol
7th Mar 2013, 17:57
Why is it, when a headlight bulb is replaced, the new one is so strong it appears as though full beams are on, but the other headlight is a dim as me for asking.

hellsbrink
7th Mar 2013, 17:59
Because one is new and isn't rather "worn out" like the other one (yes, the filament in a halogen degrades with use, same as with a normal lightbulb, so you get less light as the bulb gets older)

Dushan
7th Mar 2013, 18:13
The other one is ready to go, especially since the first one burned out there was a bit more 'juice' coming its way until you replaced the first one.

It is my experience, and practice to change car bulbs in pairs, after all they are sold that way.

wings folded
7th Mar 2013, 19:05
It is my experience, and practice to change car bulbs in pairs, after all they are sold that way.


Unless you have an unusual car, both have been lit for the same length of time.

The second will tend to fail within a short delay from the failure of the first.

OFSO
7th Mar 2013, 19:29
Much the same on NCC-1701 thru to NCC-1701-E. If one nacelle fails you change both, otherwise the assymetrical warp field ensures the starship goes where no man has gone berofe.

wings folded
7th Mar 2013, 19:35
I have never knowingly "gone berofe", but I find the expression totally charming.

"Stanley is behaving strangely nowadays"

"Well, yes, he has gone berofe".

"Ah, I see..."

I also make even greater whopping typing errors so don't get upset !!

Milo Minderbinder
7th Mar 2013, 20:46
"Why is it, when a headlight bulb is replaced, the new one is so strong it appears as though full beams are on"

Usually because most DIYers go to Halfords to get the replacement, and rather than buy the standard bulbs they go for the expensive "high intensity" options with krypton gas (or whatever.....)

Personally I use 130/90W rally bulbs instead of the road legal 55/40W ones
A damn sight safer on shitty rainy nights

G&T ice n slice
7th Mar 2013, 20:57
55/40W

I thought that was the oil?

I no nothing about cars, I have an ovloV. I sometimes get to drive it.

Capetonian
7th Mar 2013, 21:01
A friend of mine who had an oldish Golf was convinced she suffered from night-blindness, so she had the good sense to stop driving at night. We went out one afternoon in her car, ended up having dinner out somewhere in the gramadoelas (middle of nowhere) and me driving back. I started the car and switched the lights on, couldn't see the road properly, it was very dark and no streetlights. One headlight worked but only just, and the other was dead. Drove to a service station, put in new globes, the halogen ones, and J. realised she didn't suffer from night blindness!

The downside was that she then took the wheel and drove through the night like a nutter (which she was!).

M.Mouse
7th Mar 2013, 21:19
The other one is ready to go, especially since the first one burned out there was a bit more 'juice' coming its way until you replaced the first one.

I am afraid that statement is completely wrong. A lamp draws current dependent upon supply voltage and its own impedance. Unless the battery is worn out and the alternator isn't charging one lamp will draw the same current whether the other lamp has failed or not.

lomapaseo
7th Mar 2013, 21:29
Could the difference in brightness between new and old be due to the lens itself and not the filament ? Like a cataract in one eye

Dushan
7th Mar 2013, 21:43
Personally I use 130/90W rally bulbs instead of the road legal 55/40W ones
A damn sight safer on shitty rainy nights

Really? Without any kind of modifications? Seems like the heat alone inside the lens could be the problem unless some arrangements are made for better cooling/ventilation. Also the fuse should not handle the doubling of the load, and if the fuse is replaced then the wiring may be at risk.

Dushan
7th Mar 2013, 21:47
A friend of mine who had an oldish Golf was convinced she suffered from night-blindness, so she had the good sense to stop driving at night. We went out one afternoon in her car, ended up having dinner out somewhere in the gramadoelas (middle of nowhere) and me driving back. I started the car and switched the lights on, couldn't see the road properly, it was very dark and no streetlights. One headlight worked but only just, and the other was dead. Drove to a service station, put in new globes, the halogen ones, and J. realised she didn't suffer from night blindness!

The downside was that she then took the wheel and drove through the night like a nutter (which she was!).


This explains everything...

Milo Minderbinder
7th Mar 2013, 21:48
Dushan
normally not a problem nowadays with modern cars
I have had problems in the past with burnt out switches, one on a Citroen BX, the other a very old Honda Accord. Both were well over ten years ago - never a problem since, not with fuses or with wiring loom on multiple cars

Dushan
7th Mar 2013, 21:52
I am afraid that statement is completely wrong. A lamp draws current dependent upon supply voltage and its own impedance. Unless the battery is worn out and the alternator isn't charging one lamp will draw the same current whether the other lamp has failed or not.

In theory you are absolutely correct, however in practice not so much. There are a number of variables involved such as the age of the wires, corrosion of the connections etc. In practice you will find that the minute increase of "available" voltage to the healthy bulb is slightly higher when the paired one is burned that will cause it to burn much sooner that if the other is still there.

G-CPTN
7th Mar 2013, 22:23
Personally I use 130/90W rally bulbs instead of the road legal 55/40W ones

Back in the mid-1960s I used 75watt/60watt sealed-beam headlamp units (when most car headlamps were round) which gave better throw than the quartz-iodine bulbs (which were only single-filament at that time anyway) though I did have a couple of 7 inch QI spotlamps as well. There was nothing more powerful available way back then.

Since then I've fitted uprated bulbs where possible, though I don't do as much night driving since I retired from working (and driving).

Slasher
7th Mar 2013, 22:32
Much the same on NCC-1701 thru to NCC-1701-E. If one nacelle fails you
change both, otherwise the assymetrical warp field ensures the starship
goes where no man has gone berofe.

Yes a warp assymetry creates a lot of problems including relativistic time -

http://t3.gstatic.com/images?q=tbn:ANd9GcSSFNfeiCKttmXtcCTFYtcEWWb4BEgqZv8ygZEtzdY aQZOVzaOG

..With space contracting and expanding at the same time within the same
boundaries it can create time regression (but not time futurety) as well as
physical displacement outside parameters for a given warp.

Lon More
8th Mar 2013, 05:05
Back in the mid-1960s I used 75watt/60watt sealed-beam headlamp units (when most car headlamps were round) which gave better throw than the quartz-iodine bulbs (which were only single-filament at that time anyway) though I did have a couple of 7 inch QI spotlamps as well

I did about the same but had 6 of the spots/fogs on the front of an Imp. Switch the lot on and I swear the car slowed down as the dynamo took up the load.
Back then the GFs dad had a Rover 2000 and spent a load of time on the Continent. He fitted a set of Marchal headlamps that could be simply switched from left to right hand dipping
I have Xenon lights on the Yeti. On start up they do a little dance as the system works out the balance of the car. There's also a setting for eletronically changing from left to right dipping .

Krystal n chips
8th Mar 2013, 05:48
" Personally I use 130/90W rally bulbs instead of the road legal 55/40W ones
A damn sight safer on shitty rainy nights "

That's nice to know...it's possibly escaped your notice, but, there may well be other users of the same road as yourself, and, perish the thought, travelling in the opposite direction.

Still, no matter, as long as you can see the road safely, that's alll that counts really.

Loose rivets
8th Mar 2013, 06:18
I am afraid that statement is completely wrong. A lamp draws current dependent upon supply voltage and its own impedance.

Impedance? I am afraid that statement is a little bit wrong.


Blackened bulbs. There was a lot of that about after the war.

Loose rivets
8th Mar 2013, 06:20
OMGosh, here they are. Anyone remember these. And the Blue Spot. Luxury.

Two Vintage Marchal "Fantastic" Lights Austin Healey MG Jaguar Porsche TR | eBay (http://www.ebay.com/itm/TWO-VINTAGE-MARCHAL-FANTASTIC-LIGHTS-Austin-Healey-MG-Jaguar-Porsche-TR-/130854471378?pt=Motors_Car_Truck_Parts_Accessories&hash=item1e7788c6d2&vxp=mtr)

UniFoxOs
8th Mar 2013, 08:03
That's nice to know...it's possibly escaped your notice, but, there may well be other users of the same road as yourself, and, perish the thought, travelling in the opposite direction.

Still, no matter, as long as you can see the road safely, that's alll that counts really.

I only use 100/90s. I am convinced they have less light output than most of the modern car headlights. If the dipping is correctly adjusted, and used when required, they will not blind other road users. Neither will 130/90s of the same dipped power. I also don't use the extra wattage of foglights as so many drivers of modern cars seem to do.

UFO

Milo Minderbinder
8th Mar 2013, 08:24
Nice to see that PPrune's head of guilt attribution is still posting, though the Pavlovian training seems to have slipped.
Krystal, you usually manage to slag me off in minutes - this time it took nine hours. You really are the getting slow, though still predictable. Speed up girl!

Helol
8th Mar 2013, 17:41
Blimey, and I only asked about a bulb!

Fareastdriver
8th Mar 2013, 18:05
If the car has a few years and a fair amount of salty roads under its belt then a bottle of perspex polish is worthwhile. After two minutes or so you can see the outline of the light units again.

My wagon got a comment on the headlight output on its MOT and that was the reason.

OFSO
8th Mar 2013, 20:20
also make even greater whopping typing errors so don't get upset !!

I'm not upset because it's not a typing error. I refer you to the maintenance manuals for the early NGC series (sorry don't have number here but we are talking around NCC-1701) "...the nacelles generate a warp field by passing superheated plasma through a series of verterium cortenide coils..." and "in case of imbalance of (deleted) distortion of the space-time maxtrix may case the spacecraft to enter mirror-image retention space with inversions such as where no man has gone berofe". Occasionally one also finds "...no nam has noge berofe..."

If you insist I can post the nacalle maintenance manual pages here.

OFSO
8th Mar 2013, 20:29
http://i656.photobucket.com/albums/uu287/ROBIN_100/Nacelle_zpsf705d3b0.jpg

bluecode
8th Mar 2013, 20:38
I always replace both bulbs, keeping the old one as a spare but also because as mentioned it's probably going to be a different type of Halfords bulb. Had to do it recently, discovering at the same time just how awkward it can be to change a bulb in a modern car. Lots of skinned knuckles. :{

But I have found that when one goes, quite often so does the other for whatever reason. Had it happen at night in the middle of nowhere. Luckily an application of tape prevented the high beams from annihilating oncoming drivers.

One other thing, the cost of new bulbs is astonishing! Particularly the high intensity versions.

Lately though I fancy a set of bi-zenons, no not an alien bisexual race. But a set of headlights that apparently render darkness into daylight. Standard on some cars at the moment. Wonder if I can retrofit?