Since you are not planning on using the ammeter, I would connect the
output from the alternator directly to the battery, rather than using
the alternator wire in the harness that would run from the alternator to
the ammeter. It is mainly that piece of wire that burns up when
overloaded by the alternator current. (as well as the wire from the
ammeter to the starter).
As Andy mentioned, the alternator will put out only as much current as
is needed by the car. By "the car" I mean the accessory load, ignition,
lights, and the battery. Yes, the battery is a load when it is being
charged. If the battery is very low, such as when you leave your
headlights on and it is totally dead, then you jump the car to get it
started, there can be a 50A or more charging current for the battery
alone.
I'd just run about a number 6 or 8 directly to the battery terminal.
Relays to control loads is a very good way to go. I see it as a win-win
situation. It takes the load of f of the switch, and, with larger and
shorter wire from the relay to the battery or starter, will give you
more available power for the device that is controlled. Just don't
forget to add an extra fuse in the power wire to each of the relays.
When I get around to rewiring my car this winter (I hope), I plan on
running this kind of wiring, along with installing a volt meter in place
of my ammeter. I plan on using one of the Nissan battery positive
battery cables that has the 2 locations for fusible links to be
installed at the battery post (in addition to the starter cable). I will
then add a fusible link between this connector and the alternator. It is
clean and protected in case there is a short. Also, fusible links will
be stock dealer items.
Peace,
Pat
slowboy@cox.net wrote:
>I have a brand new NISSAN wiring harness setup for a 1970.
>
>I am also planning on a 50 to 80 amp alternator mod.
>
>I am not putting the ampmeter back in, instead a voltmeter will go in the hole.
>
>I'm going to things like brighter lights, fan, fogs, etc and will be putting
>in relays to operate said items and any stock items I can think of in the
>process.
>
>I have read that the stock harness won't handle the bigger alternators.
>
>My question for you electrical engineers and others in the know is:
>
>Factually, what is it about the stock wiring harness that causes its failure
>when using a larger alternator? Is it the wire size? I'd rather not build a
>new one and I don't want to do a work around.
>
>Thanks!
>
>SlowBoy (Emphassis on the "SLOW")
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