At 1:26 PM +0000 4/22/03, steve bridge wrote:
>I just parted an old Volvo with Bosch H4 headlights. What exactly does "H4"
>mean, and will I need relays to use these on my Spitfire?
H-4 is the designation for the halogen bulb in the lamp unit. It has two
filaments; one each for high and low beam. They are replaceable and come in
several different wattages for the filaments. The most common is 55/60
watt, although one can get 55/100 and 80/100. Don't get carried away with
high-watt lights, for two reasons. The first is your switchgear won't
handle anything beyond 55/60 and even if you add relays you'll need heavier
wiring. The second, and frequently overlooked, reason has to do with heat.
High output lamps get HOT. In a small enclosure the heat will diminish bulb
life. Between that and vibration, you'll be replacing bulbs several times a
year.
The Bosch lamps will go in the Spit no problem and you don't need relays,
since the halogen bulbs don't draw any more current then the stock lamps.
Over 20 years of rallying in the dark has taught me a lot about lights.
Phil Barnes (peb3@cornell.edu)
Cortland, NY (nowhere near New York City)
'71 TR6 CC61193L (26 year owner)
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