The headlight bulb most commonly fitted to modern cars and bikes is the Quartz Halogen P43t H4. There are other types H1, H2, H3 & H7, and they are covered lower down.

The standard H4 is usually 60/55w, although 100/80W and 130/90W are available for off road use.

Phillips have recently introduced the Brightest H4 Xenon bulb available. The X-treme Power H4 is 80% brighter than a standard Quartz Halogen bulb but still only 60/55W.

The X-treme Power features Chrome coloured top & base

Improved geometrical filament design

Optical finishing of Quartz glass envelope

Revolutionary gas composition

Special anti-reflex coating. £12.50 each or £25.00/pr. H4 & H7

November 2007 Auto Express test

"Head and shoulders above the rest in this test was the Philips X-treme Power, which put in a performance no rival bulb could come near".

The New kid on the block (Jan. 2008) is the Osram Nightbreaker with a claimed 90% more light which is 10% whiter.

H1 & H4 at £20.00 / pr.

This was for a long time the best H4 upgrade. I have them fitted in my van and although there may be brighter bulbs now available I'm not changing.

Still very good value £8.50 each £16.00/pr.

The General Electric is a full 60% brighter than a std. H4. Also available in H1 and H7 at 50% brighter.

The Motovision bulb also gives 40% more bright white light and a 10-20 M. longer beam than Quartz Halogen bulbs fitted as standard to modern bikes.

H4 60/55W £10.00 ea.

H7 55W £15.00 ea.

The H1 is a single filament Quartz halogen or Xenon bulb, used in twin headlamp cars or where 2 headlights are mounted in one enclosure.

As standard they would have been 55W. 50% brighter Xenon versions are available from Osram, and General Electric.

100W and 130W Quartz halogen versions are also available.

The H2 is a single filament Quartz halogen or Xenon bulb, used in twin headlamp cars or where 2 headlights are mounted in one enclosure.

As standard they would have been 55W. Brighter, more powerful versions are available

The H3 is a single filament Quartz halogen or Xenon bulb, used in twin headlamp cars or where 2 headlights are mounted in one enclosure.

As standard they would have been 35W or 55W. A brighter Xenon and more powerful Quartz Haloge versions are available.

The H7 is a single filament Quartz halogen or Xenon bulb, used in twin headlamp cars or where 2 headlights are mounted in one enclosure.

As standard they are 55W. Xenon versions are available from Osram and General electric.

6 & 12V Quartz Halogen pilot light bulb BA9s and BA15s. Bright enough to be noticed without straining your charging circuit. Direct replacement, needs no wiring or switch changes. These replace the bulbs in illustrations 25, 26 & 39 in the diagrams of standard bulbs.

The BA9s is usually found as a pilot light inside a headlamp reflector, whereas the BA15s is often fitted by itself as a side light. Miller headlamps sometimes use the BA15s as a Pilot bulb.

The BA9s 6V 10W or 20W and 12V 23W are ideal as daytime running lights.

Powerful quartz halogen bulbs for the standard BAY15d stop/tail lamp. Available in 6V 6/23W and 12V 5/35W these replace the bulbs shown in illustration 24 in the diagram of standard bulbs. These are £7.25 ea.

These fit almost everything with a combined stop/tail bulb. Some vintage cars had paralell pins.

Click here for the diagrams of standard bulbs

Offset pins