headlights, voltage

[rdh@sli.com (Robert D. Houk)]

   As my electronics knowledge is iffy, at best, could you describe exactly 
   where/how you are measuring?  Are you measuring across the bulb's terminals
   with the bulb in and on, or across the power-gnd lines with the bulb out?  
   Did you run two relays, one for each headlight?
   (See, just enough knowledge to be dangerous...)  

measure across the two terminals connected to the back of the bulb when
"on" (warning, it can get hot ... *ouch!!*). also measure either terminal
to car chassis/body/battery ground.

This will tell you how much voltage is developed across the bulb, and how
much is lost to the ground wire. On mine, the last time I measured, it was
11.8 or 11.9 across the bulb, .5 from bulb to ground, so I'm still losing
about a volt to wiring/fuses/switch/etc. (i.e., 13.5v running, 12.5 to
bulb, 12 across bulb and .5 to ground wire from bulb to ground). This is
not as good as I would like it, but it a ***VAST*** improvement over stock
Audi wiring. My mods are '83 UrQ, and are to the wiring harness itself,
no relays (yet).

I'd run separate relays for each headlight (although the normal low beams
can be driven off one relay, they only draw about 4.8 (? been too long)
amps each. With good relays and heavy-gauge wiring, you should be able to
get 13v across the filaments, nice and bright/white light!

					-RDH