Current Trivia

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

Just in case you've ever wondered how much current your headlights draw,
or your window motors (um, "regulators"?), or your starter . . .

Here are some current draws I measured this afternoon on my '83 UrQ.
(Why? Weellll . . . it wasn't exactly that I was bored . . .)

Current draw (damp, 68F):

  Cold Engine, Off

	Starter:	101 - 105 Amps

	Lo-Beams:	 8.0 Amps
	Hi-Beams:	18.4 Amps

	Rad fan - Lo:	 5.2 Amps
	Rad fan - Hi:	18.1 Amps

	Air fan - Lo:	 2.0 Amps
	Air fan - 2:	 3.7 Amps
	Air fan - 3:	 5.9 Amps
	Air fan - Hi:	 9.1 Amps

	Rear Defrost:	 7.7 Amps
	
	Stereo:		 2 - 5 Amps  (Loud as I can stand it)

  Warm Engine, Off

	Starter:	112 Amps

	Ign. On:	 3.5 Amps (all acces/lights/etc off)
				  (I recall that the fuel Control Pressure
				   Regulator and Aux Air valve together
				   consume aoubt .9 amps, implies ECU is
				   using "about 2" amps)

  Warm Engine, Running, ~13.5 Volts

	Lo-Beams:	 8.4 Amps
	Hi-Beams:	20.1 Amps

	Rad fan - Med:	11.9 Amps
	Rad fan - Hi:	22.3 Amps

	Window Down:	 3.9 Amps (Passenger side slightly less)
	Window Up:	 9.9 Amps (Passenger side slightly less)

  Initial charge current (battery drained by ~1:00 of "starter drain")
  engine at idle (~950 - 1000 rpm):

	 0:00		45 Amps
	 0:15		33 Amps
	 0:30		31 Amps
	 1:00		28 Amps
	 2:00		26 Amps
	 5:00		24 Amps
	15:00		17 Amps

  Increase of current at 3000 rpm -- .1 - .2 Amps

Two observations. First, in general, "reving" your engine doesn't help it
charge significantly faster (it might if the battery were really drained),
so driving around to charge up your battery is generally just a waste of
gas . . .

Second, Audi has the fresh air fan and radiator fan high-speed circuit
(as engaged by the A/C, and not by "overheating") routed through a common
25 amp fuse. And I wondered why the fuse holder in my car was literally
melted . . . (and this is the "early wimpy" radiator fan, not the later
high-power radiator fan that the car probably really needs!). Those of
you with TQC's take note! Might even affect coupes (of the early/mid
'80's vintage), and who knows what other members of the family Audi.

One smart high school nerd, that's all I ask that Audi hire, one simple
smart kid . . .

					-RDH