Re: Amp gauge

[SailingFC@aol.com]

I have installed an ammeter on my '78 Scirocco.

The way I have it hooked up is to monitor the charging state of the battery.

What you are trying to measure is the current flow into and out of the
battery.  I also have two red wires coming from the connector of the
alternator.  This is the curious part.  When I traced the harness to the
battery tonight, there is only one red wire coming out of the harness to the
battery.  In the Bentley manual it shows two wires all the way to the
battery.  I am thinking VW or maybe I combined the wires inside the harness
somewhere, because the resulting wire is larger than either of the two coming
off the alternator(I did this so long ago I don't remember if I made the
modification).  Anyway, this single red 10AWG(gauge) wire now runs to a
terminal strip mounted to the inside driver side fender where I then run
another red 10AWG wire into my interior through one of the harness boots and
to the "+" terminal of the gauge.  From the "-" terminal of the gauge a black
10AWG wire runs back out to the positive post/terminal of the battery.
 That's it.  Now this wire carrys full current from the alternator and must
be well protected.  All the connections must be tight.  If you can go larger
on the wire guage, do it.  It gets to be a pain working with large gauge wire
because it's so unflexible and hard to route.  Now on the terminal strip, I
have 10 AWG wires jumpered across to power the other terminals which I have
now attached all the accessories and more that were attached to the positive
post of the battery.

When the engine is off, the meter will show me current going out of the
battery by registering "-" (discharging) when something is turned on.  When
the engine is running, say after I just started the engine, the ammeter will
show "+"(charging) to replenish the power, back to the battery, that was
consumed to turn the starter.  When I switch on a major accessory, while the
engine is running, if the alternator can keep up with the demand you will see
no current draw from the battery because the alternator is supplying all the
power and there is no need for current to flow from the battery.

I've thought about putting a fuse inline to protect the circuit in case of a
short, but you would have to put a fuse in that is above the charging
capacity of your alternator or else you'd blow the fuse after you started the
engine from a long session of stereo blasting.  That would be a 70amp or
higher fuse for me(65amp alternator).  Needless to say I haven't done it yet.
 No problems yet..
   knock   <=  "knock on wood"
   wood.

Like many projects, disconnect the battery(or even better, take it out)
before starting any of this.

Sorry for the long message, I tend to be long winded.

Good Luck.
SailingFC@aol.com
'78 original owner.
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