Upgrading to high output alternator

[RSB333]

Upgrading from old automotive type alternator to new, 90 amp with external regulator. The old wiring harness ran the output from the alternator up to the instrument panel's ammeter and back to the battery switch. It seems current best practices run directly from the alternator to the battery with proper fuses. Can I keep the old wiring to the ammeter while running new (larger) wire directly from the alternator output terminal to the battery bank?
RSB333

[Stu Jackson]

Yes, you could, but: The ammeter has to be in series with the load.


Ammeters & Shunts 101: http://c34.org/bbs/index.php/topic,6032.0.html


Ammeter location depends on what kind it is and where you run the wiring.

[smac999]

asuming it's a old current gauge (with no shunt) no. just remove it and the wiring. if you try to wire both it will just show random numbers as a small portion will take the path though the gauge and most will bypass it through the new direct wire

if it does have a shunt it will work as long as the gauge goes high enough. but lots of older boats have the non shunt gauge. which is a super horrible design. with 50' of 10awg wire trying to pass the charging current. just rewiring your existing alt direct to battery will probably double or triple your charging.

if you don't have a battery monitor get one. you'll get net amps into the bank instead of alt amps.

[RSB333]

Thanks! I do have a Link Lite monitor, and will now take out the old ammeter loop and wire the alternator output directly to the starter with heavy gauge wire.
RSB333

[mitiempo]

Originally Posted by RSB333

Upgrading from old automotive type alternator to new, 90 amp with external regulator. The old wiring harness ran the output from the alternator up to the instrument panel's ammeter and back to the battery switch. It seems current best practices run directly from the alternator to the battery with proper fuses. Can I keep the old wiring to the ammeter while running new (larger) wire directly from the alternator output terminal to the battery bank?
RSB333

Remove the old ammeter and replace it with a voltmeter. It will tell you whether you are charging or not.