Re: Light research (silliness)

[Heather & Jeff <hjr@buffnet.net>]

> >It is the alternator that is producing the electric power when the
> >engine is running.  That's why you want to run the lights off the
> >alternator - to get the highest voltage possible.  The battery only
> >delivers current during starting; the rest of the time it is being
> >recharged.  As far as the lights are concerned, it is a giant capacitor.
> >
> >Luis Marques
> 
>         I'm no electrical engineer, but doesn't routing via the battery
> "filter" out any AC ripple that may be coming from the alternator and
> shortening bulb life? Just a question...and a thought.
> 
>                                         Happy motoring,
> 
>                                                         Shef
> 

No, routing via battery does not filter the AC component appreciably. 
Yes, the battery does have some "capacitive" effect on reducing ripple,
but what I best can tell the argument Luis is trying to make really
concerns reducing the effect of voltage drops in the system, and
attaching directly to the alternator gives you the highest voltage in
the system.  Also, the ripple in a typical charging system has no effect
on bulb life.  However, voltage does_have_a_very_big_effect on bulb
life.  Raising your voltage a few tenths of a volt has a marked effect
on lowering life.  Some large truck fleets specify a alternator with
slightly lower voltage set voltage when buying their trucks.  (typically
13.8 volts versus 14.0) They save thousands of dollars in light
replacement costs this way.

Bottom line:

Connect to the Battery= slightly lower brightness=longer life
Connect to the alternator= slightly higher brightness=shorter life

Jeff Waterstreet
Director Sales and Marketing
Leece-Neville div of Prestolite Electric (we makes alternators & stuffs
like dat)

'88 80q (obligitory Audi reference)
 

Anyway, the battery does act somewhat like a capacitor and reduces the
ac ripple component, but who the hell cares?