Skip to main content
Gerry | Vanagon
Checking account...
← vanagon.com home · Continue the discussion in the forum
Subject:Re: Headlight relay upgrade?_wire sizes
From:David Beierl
Date:Sun, 4 Jan 2004 18:36:42 -0500

At 03:39 PM 1/4/2004, David Marshall wrote:
>Is it just me or is this email considered offensive?
>
>Speaking of bullshit... YOUR answer is bullshit.

George is known to be...um...ah...brusque with incorrect info or other
things he disagrees with.  No, I cannot tell a lie, he's downright rude,
not quite the same as offensive I think, but no doubt he leads an
interesting life. :-)

But it's true that your formula is wrong (E = IR, it's *C* that = pi r^2)
and your guess of half an ohm for the wiring resistance is really
outrageously high*, and would indeed result in the voltage drop George
mentioned -- except that the circuit would no longer be consuming 210 watts
at that point and you get to follow Mr. Newton down the rabbit hole of the
Calculus of Infinitesimals to find out where it would actually
settle.  Also, unless you're running your Vgon at sea or in dilute nitric
acid, not likely that much will change in the wires themselves over
time.  The crimps and switch contacts and such are another matter.

*The actual resistances are low enough that they would probably be commonly
expressed in Siemens, the unit of conductivity which is 1/ohms (the old
name was "mhos").  Most people don't have access to a meter that will
measure such low resistances and in any case it's the voltage drop that we
mainly care about in troubleshooting -- if it's too high there's a problem,
so fix the problem until the drop becomes reasonable.  If for some reason
we care about the resistance, it's calculated from the current and voltage
drop.

You're on the right track with the wiring, just have some numbers wrong...

:)
d

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