"Douglas St. Clair" wrote in message
...

This all takes place in a
1970 Century Resorter, and the existing wiring was obviously "modified"
during the various projects of previous owners.

I am not famialiar with this boat, is it some sort of runabout?

Is the only source of charging from the alternator, or do you have battery
charger, solar panels, etc.?



Lead Up Question #1
I'm confused on how the Battery, Alternator, Amp Meter and Ignition are
wired. There are three terminals on the back of the amp meter: [Wire to
Battery Ground], [Wire to Battery Positive], [Two Wires: 1 from Alternator
and 1 to Ignition].

Are you saying that one terminal connects to ground, the second terminal to
battery positive, and the third terminal has two wires on it, connecting the
alternator and ignitions switch together?

The terminal connected to ground confuses me, unless it is somehow related
to a light. Perhaps a light bulb plugs into the back of the case some how
and makes its ground return through the case of the ammeter.


The wire to the ignition is the "hot feed" to the
ignition. It's always on even when the Alternator is not producing power.
It appears that the two positive terminals on the back of the amp meter
(one
from positive battery the other from alternator) are both always hot. Are
these simply common terminals?

Ignore the ground connection for now.

The standard connection for an ammeter is to connect the output of the
alternator directly to the "load". The ammeter then connects between this
common load connection and the battery. If the alternator is not producing
sufficient current to supply the load then current flows from the battery,
through the meter to the load, making the ammeter read negative (discharge).
When the engine starts and the alternator provides output the draw from the
battery decreases. If the alternator is providing the exact amount needed
by the load then no current will be flowing through the ammeter and it will
read zero. As the engine RPM picks up and the alternator provides more
current than is being used by the load the excess will flow through the
ammeter to the battery, making it read positive or "charge".

The two main connection to the ammeter will be made with large wires as they
have to be able to carry the maximum output of the alternator. It is also
possible that the ammeter is a "shunt" style, where the big wires connect to
a shunt that can be located somewhere else and then small wires connect
between the shunt and the ammeter.



Lead Up Question #2
The positive lead that goes from the battery to the amp meter is split by
a
small cylinder "thingy" mounted behind the dash board with a "40" on it.
Is
this likely a master 40 Amp Fuse?

Yes


The Main Question
How should the new Fuse Block be wired in? Where should it exist in
relation to the wires described above?

If the fuse panel is very close to the ammeter then you can add a third wire
to the "ignition" terminal of the ammeter and run directly to your fuse
panel. Since this wire will be unfused it creates a risk should it break or
be shorted out, therefore you wouldn't want to make a long run this way. If
the fuse panel is going to be more than a foot or two away then you should
either install another "master fuse" between the ammeter and your fuse panel
or connect your fuse panel to the other side of the existing master fuse.


Unrelated "What the heck?" Question
My stern light has a positive lead coming from it's switch. The negative
lead is terminated on the gas tank's sender unit (a perimeter screw, not
the
center screw which I assume is the "sender"). As far as I know, the gas
tank is not grounded to the engine or the battery. The only other wire
coming out of the sender unit goes directly to the Fuel Gauge. Is the
light
grounded to the fuel tank?

The gas tank should be grounded to the battery. For one thing, the gas
gauge wouldn't work unless the sending unit had a ground, and the sending
unit normally grounds to the tank.


Rod