----- Original Message -----
From: "Herbert Miller" <hgmiller3@qwest.net>
To: "'Bill L'" <pythias@pacifier.com>; <spridgets@autox.team.net>
Sent: Sunday, February 15, 2009 9:14 AM
Subject: Re: [Spridgets] Relays
> Comments on relays:
> As commented in a previous post "for max light output place the relay as
> close to the headlights as possible" I don't see the rational. If the 12v
> wire to the relay and the relay wire to the headlights are the same gauge
> and construction there would be no difference in the voltage drop no mater
> where the relay is placed.
That's the beauty. The wires don't have to be the same gauge. Using a
relay allows you to run a larger gauge wire, that is one of the reasons
there will be less of a voltage drop. You want the run with the larger wire
to take you as close to the lamp as you can, the more of the circuit that
you can run on the large gauge wire, the less of a voltage drop. Also,
there is already a natural splice in the line, as the factory runs the wire
out to the cowl, then uses a 4 way bullet connector as a poor man's junction
box. Remove the bullet connectors, replace with spade connectors, and
attatch to the relay, no cutting of the harness necessary.
>Further, to run a heavy gauge 12v wire that is
> always hot a long distance through the chassis adds risk. Think Bugeye, up
> around the bonnet hinge and forward under the bonnet. I would rather have
> the headlight leads only powered when the lights are on, a small
> percentage
> of the time. Besides if a problem occurred in the headlight lead it could
> be
> quickly turned off.
Benifit #2, the factory harness has NO provision to fuse the headlight
circuit. Adding an inline fuse where the feed wire attatches to the starter
solinoid removes the risk of a short in the headlight circuit burning your
car to the ground. I've experienced an electrical short, and trust me, you
ain't gonna be fast enough at night to figure out that it is the headlight
circuit and get it shut off before the harness has melted itself into a
useless mass of goo.
I've also added a relay to my heater fan circuit. I picked up 2 volts at
the heater motor, and dramatically improved the efficiency of the
defrosters. It went from 10.5 volts to 13.5 volts measured at the motor.
That's a 20% increase in power to the blower motor.
Dave R.
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