3 wire alternator wiring

Royse · Nov 12, 2015

I've wired quite a few of these alternator setups.
I normally wire them the same as JMOR's wiring diagrams show.

I have one here that is wired with the excite wire hooked
through the key switch to #1, normal, but then it is also
jumpered to #2 for the sense voltage.

There's no diode or light on this one (and it shuts off fine) so
I don't see a whole lot of difference electrically other than the
resistance of the key switch and wiring length, which are minor.
Still battery + to sense wire.

It charges fine and has for 5 or 6 years that I know of so I am
not planning on changing it unless you guys see a reason to do
so that I am missing.

old · Nov 12, 2015

Well all the sense wire has to do is know how much volts are in the battery to shut down or slow the charge so it should work just fine that way. I have seen many ways of hooking up a 3 wire and have one on an Oliver S88 that has a ballast resister in the wire for the #1 and it works just fine that way

Joe Mindy · Nov 13, 2015

Royse, you stated that it shuts off ok without a light or diode in the excite wire going to number 1 terminal. This could imply that there is quite a bit of resistance in the key switch and its inherent wiring. Usually they will "run on" when wired this way. You state the #2 sense terminal is jumped to the #1 terminal. If there is higher than normal resistance in the #1 circuit, then the alternator is sensing less than battery voltage and could overcharge the battery.

JMOR · Nov 13, 2015

(quoted from post at 22:12:59 11/12/15) I've wired quite a few of these alternator setups.
I normally wire them the same as JMOR's wiring diagrams show.

I have one here that is wired with the excite wire hooked
through the key switch to #1, normal, but then it is also
jumpered to #2 for the sense voltage.

There's no diode or light on this one (and it shuts off fine) so
I don't see a whole lot of difference electrically other than the
resistance of the key switch and wiring length, which are minor.
Still battery + to sense wire.

It charges fine and has for 5 or 6 years that I know of so I am
not planning on changing it unless you guys see a reason to do
so that I am missing.

oyce, you probably know by now that I came through the "If it ain't broke, don't fix it" school. But many insist on "fixing it until it is broke". Check your ign switch, as it may have an auxiliary contact/position, which separates coil from alternator excite connection.

3 wire alternator wiring

Royse

Well-known Member

old

Well-known Member

Joe Mindy

Member

JMOR

Well-known Member

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