| The Test

You
can retro-fit super-bright xenon lights to a growing number of cars,
but for most of us, replacing the bulbs is the only option for
improving safety as the nights get longer.
After all, equipping your Ford Focus or VW Golf with a
top-of-the-range gas-discharge system could set you back well over
£1,000, while a decent pair of bulbs is only around £20. As we have
learned from previous headlamp bulb assessments, though, the variation
in performance between best and worst is vast.
Judging by your response to past tests, night visibility is a high
priority, and many of you are keen to up-grade. Yet the industry does
little to help the motorist. While there's a wide range of products,
they often use bewildering or misleading names. Confusion often arises
over gas discharge or xenon lights, as seen on BMWs, Mercedes and
Audis. These use a totally different technology from that of
conventional bulbs, as the source of light is an arc burning between
two electrodes in xenon gas rather than a filament. The result is a
bright blue-white glow.
But manufacturers also put xenon into conventional halogen bulbs -
for longevity - and claim higher performance. How many motorists have
bought these, thinking they were going to get the same units as used in
the BMW 7-Series?
Power claims can be misunderstood, too. The most common one is '30
per cent extra' light, but a standard 12V bulb with such a high output
would be illegal. The figure refers to the amount of light on the kerb
75 metres ahead of the car - a critical point for night driving.
This stronger light is achieved by burning a smaller filament
harder, to give a tighter focus to the beam. Philips and Osram make 50
per cent brighter bulbs, and some examples claim 'plus 60 per cent',
although they were launched too late for this test. We assessed plus
50, plus 30 and standard bulbs - in general, expect to pay more for
better performers. A further complication is blue bulbs, which aim to
give a BMW or Audi look using filters or coatings to achieve the
colour. These coatings actually cut light, and coloured units perform
poorly. Don't confuse these with all-weather bulbs, which have a yellow
beam for driving in fog.
Unlike most of our tests, you can't just pick a pack off the shelf
to get the bulb we tested. Philips, Osram and GE supply car makers, and
build bulbs to their customers' standards, which are higher than the
law requires. Buy one of their packs and you get one of their bulbs.
Others, such as Halfords, Lucas, Bosch and Hella, use suppliers, and
regularly change them. The only way to ensure you get what we tested is
to read the name etched on the base.
We returned to Philips' test centre in Aachen, Germany, where our
last test had been carried out. All the bulbs were seasoned for an hour
to settle output before power draw and light production were measured
in a photometric sphere. Build quality was checked, particularly the
position (geometry) of the filament and shield, as these have the
biggest effect on the beam. Finally we went into the light tunnel,
where the dip beam was measured for glare and light on the road. To get
an overall rating, we added the light measurements for 50 metres ahead
at the centre and edge of the carriageway, plus twice the 75m kerbside
figure.
Where a bulb failed to produce a beam within UK legal requirements,
it received only one rating or star. All our test samples were bought,
to prevent 'filtering' by manufacturers, and the cost quoted is what we
paid for a pair. However, price had no influence on our results, as it
varied so widely among sources. The lighting tests we carried out were
overseen by AA Technical Information Centre engineer Rory Stockbridge.
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Halfords High Performance |
Rating:
Price: £18.98 (shop)
Type: Premium plus 30 per cent
Beam: 73.7
Produced by Philips' east German subsidiary Narva, this bulb
was a letdown for the high street chain and outperformed by several
cheaper standard alternatives. It was down on all the readings and
there was little sign of the claimed extra 30 per cent light at 75m. |
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Bosch Xenon Power |
Rating:
Price: £18.98 (shop)
Type: Premium plus 30 per cent
Beam: 84.9
If you are in Halfords choosing between its own brand and the
Bosch version, this should make the decision easy. Underneath the
labelling is an Osram product which, as you'd expect, performed well
across the range, giving a good, even beam without dark patches. |
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Lucas Premium Xenon |
Rating:
Price: £21.15 (RRP)
Type: Premium plus 30 per cent
Beam: 86.7
Lucas will be pleased to come in only a fraction behind Philips
and Osram, but it's not surprising, as this is an Osram-made bulb. Its
superiority over lesser performers was very noticeable in the light
tunnel, particularly at the 50m mark. |
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Hella 30 per cent brighter |
Rating:
Price: £11.65 (factor)
Type: Premium plus 30 per cent
Beam: 83 No fancy packaging or sales hype from top headlamp
maker Hella, but the bulb, by Osram, performs reasonably. As with the
Lucas, it showed well at 50m only to fall back further down the road.
But it had a good, even beam with no dark patches. |
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Ring Xenon Plus |
Rating:
Price: £9.37 (factor)
Type: Premium plus 30 per cent
Beam: 82.6
As with Halfords' unit Ring's Xenon Plus comes from Narva, but
it really pushed the limits of light output and had a high power draw.
However, that did not lead to a good beam pattern - its 75m score was
the worst in class. On the wall, it had a good cut- off, but the main
centre of light was small. |
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Philips Premium |
Rating:
Price: £21.12 (mail order)
Type: Premium plus 30 per cent
Beam: 87.7
A best buy for Philips in the plus 30 category is revenge for
its defeat in the plus 50 class. As we paid for mail order delivery,
the price was pushed above that of VisionPlus or Silverstar. From a
shop, it would be less. A great performer, particularly at mid-range. |
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Osram Super |
Rating:
Price: £12.26 (mail order)
Type: Premium plus 30 per cent
Beam: 86.9
The Super chased Philips' Premium, its original-equipment rival
hard, and achieved its result with a lower power draw and light output,
leading to a Recommended award. Essentially, however, there is nothing
to choose between these top brands. |
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The best models in this test are plus 50 per cent bulbs. And, as their
prices have dropped since they were first launched, they have become an
even better prospect. In this class, Osram gets the nod over Philips.
The tables are turned in the premium plus 30 sector. These two top
categories are the preserve of the original equipment producers and
anything with Philips or Osram on it is a guarantee of quality. For the
standard bulbs, Lucas just gets the nod over Motaquip.
As in previous tests, we have not chosen a blue bulb, as we feel
these are purely fashion items which perform significantly worse than
the other categories. If you must have a pair, go for the Philips or
Osram - either own-brand or in a Lucas pack.
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