Date:         Thu, 5 Jun 2003 17:57:24 -0400
Reply-To:     David Beierl <dbeierl@ATTGLOBAL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@ATTGLOBAL.NET>
Subject:      Re: So... what is the answer for these poor lights?
Comments: To: Damon Campbell <damoncampbellvw@yahoo.com>
In-Reply-To:  <20030605204409.90169.qmail@web13102.mail.yahoo.com>
Content-Type: text/plain; charset="us-ascii"; format=flowed

At 04:44 PM 6/5/2003, Damon Campbell wrote:
>Is it really necessary to run 4 wires with the
>corresponding 4 relays?  Is this just to prevent
>losses by halving the current through any one wire, or
>for redundancy, or something else my electrically
>feeble mind can't follow...

Strictly so that a short in one feed won't knock out both (or all four)
beams.  VW fused the feeds individually but they all combine, I'm too lazy
to look up which side of the headlight switch.  But since you're running
new feeds anyway, might as well eliminate a few more single-point failure
sources.  Depends how paranoid you are and what happened to you the last
time your lights failed. <g>  Alternatives would be one big fat one with a
"fusible link" (big fuse, unless you're an Americen car) at the battery to
feed the relays, and fuse the four relay outputs, or two feeds (high and
low or left and right as convenient) with big fuses at the battery and four
smaller ones on the relay outs...but the closer to the battery you can get
independent feeds -- rearranging the control wiring so that it uses the
same independent feeds would be better yet.  Of course you 2.1l folks have
lots better fuse panels than the 1.9l...less likely to self-destruct.

david
ps -- there's no end...surplus aircraft emergency (wind-powered)
generators, backup batteries, carbide lamps... ;-)


--
David Beierl - Providence RI USA -- http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"