Date:         Sat, 3 Jan 2004 13:05:25 -0800
Reply-To:     David Marshall <vanagon@VOLKSWAGEN.ORG>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Marshall <vanagon@VOLKSWAGEN.ORG>
Subject:      Re: Headlight relay upgrade?_wire sizes
Comments: To: Sglw@aol.com
In-Reply-To:  <d1.2736bb4.2d287c50@aol.com>
Content-Type: text/plain; charset="us-ascii"

Yes.  The skinnier the wire the more resistance it has.  The more
resistance, the more voltage drop and the lower the voltage and the light
output will be less.

V=IR^2 is an important formula to remember.

Constants:
Battery Voltage = 13.5V
Bulbs = 2 x 55+60W (Standard 86-91 Vanagon on high beams)

If the bulbs were connected directly to the battery they would consume 15.5
Amps of current:

P = IxV
210W = Ix13.5V
I = 210W / 13.5V
I = 15.5 Amps

Let say there is 0.5ohms of resistance between the battery and the headlight
with the factory 14ga wiring.  It is probably more, but we're all driving a
nice Vanagons.  The voltage drop at the lights would be:

V = 15.5A x 0.5ohm ^2
V = 15.5 x 0.25
V = 3.875

Our voltage at the lights will now be 13.5 - 3.875 = 9.625V which gives us
an effective 150W of light (P = IxV)

If we are to use fatter wire, there would be less resistance.  If the new
fat wire we run has half the resistance of the original (probably even
better!) for a total resistance of say 0.25ohms it would come down to:

V = 15.5A x 0.25ohm ^2
V = 15.5A x 0.0625
V = 0.96875

Our new effective output would be 13.5 - 0.96875 = 12.53V which gives us an
effective 194W of light.

As our Vanagons get older there is more corrosion in the wires and this
creates resistance.  Every switch, connector etc in the circuit adds
resistance.  Resistance is our light output enemy!
David Marshall

Fast Forward Automotive Inc.
4356 Quesnel-Hixon Road
Quesnel BC Canada  V2J 6Z3

http://www.fastforward.ca    mailto:sales@fastforward.ca
Phone: (250) 992 7775        FAX: (250) 992 1160

- Vanagon Accessories and Engine Conversions
- Vanagon, Transporter and Iltis Sales and Importation
- European Lighting for most Volkswagen models

  -----Original Message-----
  From: Sglw@aol.com [mailto:Sglw@aol.com]
  Sent: January 3, 2004 12:13 PM
  To: vanagon@VOLKSWAGEN.ORG
  Subject: Headlight relay upgrade?_wire sizes


  Do you mean that the standard wiring in my 87 vanagon is not adequate & I
would get brighter lights with relays & fat wires?

  Sam W
  63 singlecab
  70 bay Westy
  87 Vanagon Westy