Dear Richard,

According to my dealer I am running at 13.7 volts. I cover about 25,000 miles per year and the bulbs have been lasting about 3-4 months. Thus about 6250 - 8333 miles. I do NOT run with headlight on during all of this so perhaps about 60% is with lights on and 40% lights out.

That gives me a maximum of (60% of 8333) 5000 miles. Using your average speed of 40 mph which I would not disagree with that equates to 125 hours as the bulb lifetime. This still falls well short of your estimate of 500 hours being halved if the voltage is 14.0 volts.

Is there anything you can suggest in order to extend my bulb lifetime without having to make significant changes to the car. Perhaps there's a higher spec. bulb in your range, though if that were to be very costly it may ben that I will simply have to give up as suffering bulb failures every 3 -4 months is not something I can put up with.

Looking forward to your comments

Regards

Steve Newman


-----Original Message-----
From: Richard.Marples@CRO.LIGHTING.philips.com [SMTP:Richard.Marples@CRO.LIGHTING.philips.com]
Sent: 30 November 1998 13:51
To: Steve Newman
Subject: Re: WWW: lighting - UK - GENERAL

Dear Steve,

The Xenon Premium bulbs were developed to give 30% extra brightness
whilst remaining within legal requirements. We do this by over running
the filament and making it burn brighter. Xenon gas is a heavy, large
molecule, inert gas. We use this to slow down the evaporation of
tungsten from the filament and give us a decent life time.

Unfortunately the life time of Premium bulbs is not as high as
standard bulbs, however we still get around 500 hours at 13.2 volts.
(500 hours at an average of 40 mph gives 20,000 miles constant
burning!!!)

One of the biggest influences on life time is voltage. A car running
at 14.0 volts instead of 13.2 volts (13.2V is the European test
voltage) will approximately halve the life time of the bulbs. Premium
bulbs are particularly susceptible to excess voltage because they are
already being over run. Therefore if your car has just a slight
over-voltage (and most cars do these days to compensate for the high
energy demands) Premium bulbs won't last all that long.

Unfortunately, like most things in life, there is a compromise - more
light or more life time?

I hope this explanation helps and if I can be of any further
assistance please do not hesitate to contact me.

Richard Marples,
Philips Automotive Lighting.


______________________________ Reply Separator _________________________________
Subject: WWW: lighting - UK - GENERAL
Date: 30/11/98 12:34


Name : Steve Newman
Comments:

I have recently posted details of problems which I have been having
with early failure of H4 Xenon bulbs sourced from Halfords in the UK.
These are lasting only about 3 - 4 months and I am now on my 3rd pair.

Halfords have given excellent service in replacing the failed items
but I am concerned that this does not appear to be a one off failure.

I have had the car checked by the servicing dealer and they have confirmed
that all is ok with the electrics. Each time the Xenon bulbs fail
I have replaced the original halogen items and these have never failed.

The car is a May 1997 Subaru Impreza Turbo with no modifications.

Any suggestions/advice you can offer would be greatfully appreciated.

Please feel free to email me direct of phone on the above address/number.

TIA

Steve

I'm currently finding the same short filament life with Ring Xenon bulbs which have lasted approx 7 weeks of which a small amount of driving was during darkness. May be a "one off" but I suspect not, are other users experiencing similar problems ?.

Oh dear. I had hoped that I might escape the "early bulb failure" syndrome when Bell & Colvill fitted Ring (ie not Philips) Xenons for me too.

They've now been in for 10 days - no problems so far, lots of use. I'll post an update if I experience problems.

Meantime, I'm off home to read up on how to change the bulbs (Just in Case :<)

Cameron

Well it was NOT a "one off" the second bulb has just gone also, so it appears to be an expensive option to fit Ring Xenon bulbs if filament life is less than 2 months. Its back to the drawing board the old bulbs are back in and a set of Cibie driving lamps are on order.

I have a set of Xenon bulbs qhich Andrew Batters kindly sold me about 8 months ago. I even changed them when I changed my car, so they have done about 12,000 miles so far without problems.

I can't remember which make they were, but possibly Osram. I also bought a set for my wife's car, and they have run without failure for the past 8 months also.

Perhaps these are isolated incidents, but I have heard of plenty people having problems with the bulbs available fom Halfords.

It will be interesting to see if these PIAA super white bulbs last a reasonable length of time, as I may get a set of these as well as the Cibies http://bbs.sidc.co.uk/smile.gif

Had a set of Xenon bulbs fitted (purchased from Halfords) on my 1000 mile service. 10,000 miles later one of the bulbs has failed. 30% of my driving is at night. However, I don't think this lifetime is good enough so I will be using the standard bulbs from now on. ** Pete Croney ** if you read this, have you decided whether or not you are going to supply clear covers for the Cibies? **

My experience seems the same. A pair of bulbs has lasted 3 weeks (both going within 24hrs of each other). Back to the originals!

Andy Batters supplied me with some Philips Xenon bulbs and no problems so far (after approx. 1200 miles of night driving - 3 months). It seems that the Ring bulbs from Halfords are causing most problems. Steve Newman - have you progressed the issue with Philips any further? Anybody having problems with Osram bulbs? If we are going to learn anything about this problem we need to be clear on what makes people are using and the estimated number of hours use.

I fitted the "Electric Blue" version of the xenon bulbs and this seems to give more light and also a very clear white flood. They have only been a week or so and no problems to report. This is on a 98my 4 door. I'll keep you posted. By the way, although it does say blue, they are no where near as blue as the new BMW's and the Senator's.

Try fitting a 12V voltage regulator to the supply of each bulb. A quick look through the Maplin or RS catalogues should reveal a suitable regulator, but it will need to be 'fitted', by which I mean breaking the cable, soldering connectors and fitting the reg.

More Info from Philips follows:
**Philips Info**
We changed the filaments on our Premium bulbs in March 1998. This
means that all Premium lamps produced after this date will be the new
longer lasting ones.

On the ring of the bulb looking from the top are the name and type
numbers. On the right hand side is the E1 mark (E1 2C3) followed by
the production date code. This will be a number followed by a letter
with two numbers underneath.

The number and letter on the top indicate the year and month. For
example 8C is March 1998, 8J is September 1998 (we don't use I).

Two new Premium lamps are being sent to me and I will forward them to
you as soon as they arrive. I would be interested to know what date
codes you have on your failed Premiums.....?
**End**

Note: All bulbs which I have acquired from Halfords have been in Halfords own brand packs but manufactured by Philips.