Alternator questions

Working with what's there... Wires on alternator were cut when I bought the Cub. Will the lower part of my drawing work? Top is how it's wired up.

NO,
The ammeter will only show charge, not discharge.

Well ... It's a gauge of some kind....

A battery wire runs from the battery to the solenoid.
A 10 gauge wire runs from the solenoid to the amp gauge.
Everything else coil; alternator excite wire; lights; what ever hooks to the other side of the amp gauge.

That excite wire will work if you can remember to turn the switch off every time you park tractor.

Here.
Don't say I never gave you anything.

When not running does the gauge needle stay centered or does it drop. If centered amp gauge of drops volt gauge

It will work as you wired but you need a diode between switch and alternator that allows current to go to alternator with switch on but will not alike current to flow from alternator to switch once tractor is running!! Without it your tractor will continue to run when you shut switch off!!!

Where are you powering the coil in the bottom drawing?

To do it without a diode or resistor, you will need a separate circuit for the coil, otherwise it won't shut off, it will feed back from the alternator.

Go by the drawing John sent.

Note the amp meter wiring, only the battery goes to one side, everything else including the alternator feed, ignition feed, lights, all go on the other side. If it reads backward, reverse everything.

You can substitute an instrument lamp for the diode if you can't find the right one. It doesn't have to be visible, can be hidden under the dash.
Optional Lamp Socket

Search back thru the archives and you can find dozens of wiring diagrams for what your needing, few things I have learned over the years doing this is always wire one side of the ammeter to the battery junction block i.e. starter solenoid or equivalent, all other circuits feed off the opposite side, easy test to make sure its wired right, with the battery connected correctly, engine off , turn on the lights or ign. and see if the needle moves toward discharge if so your wired right, if not switch sides with the wires . Be sure to use an ammeter with and amp capacity to match the alternator. If using a 2 prong on off switch install a small diode in the exciter wire for the alternator to stop feed back, if there is room use a 10SI Delco alternator for cost, reliability and ease of wiring, if not there are several different models with a smaller frames to accommodate hood and mounting restrictions, most of which are simple to wire up. I DON'T USE one wire alternators of any kind because of past issues, and try to not volt meters not that they don't work. You can also use your 6 coil by installing a resistor between the switch and the coil.

Gauge picture

Doesn't show zero not running!! Lol

John, after a friend had a mouse chew a wire and set a tractor on fire, I use quick disconnects on every tractor.

That is an amp gauge but not showing zero may mean it is bad or it just doesn't work as it once did. If you have a way to put a load on the gauge like hooking a head light etc. to it on the load side and if it moves to discharge it is working as it should

NAPA has the flat 2 wire plug that plugs into the alternator that has a diode on it!

That diagram that John posted is correct but adds a lot of unnecessary detail to follow with the added terminal block. I will link a much simpler one. The indicator lamp can be as Steve@adv. posted.
Poke here

Or a diode which is more reliable

If you want to keep it simple the bottom drawing will work OK. The amp gauge will only show charge from the alternator but in a simple system like that with a minimum of draw you don't need to worry if the alternator is keeping up or not. The alternator probably has way more capacity than you ever will need even if you had ten lights shining. Now if you want to wire it good and proper you will want to wire it like John's diagram. If the alternator gets weak it can be down to a 3 or 4 amp charge and still keep up with the ignition.

This post was edited by fixerupper on 12/26/2021 at 05:49 pm.

Old,
It has to be an ammeter. Can't run current through a voltmeter to charge the battery.
All loads need to be connected to the side of the ammeter that is connected to the alternator.