1948 8N 12V front coil-Electric circuit question

Never was good at electricity...In this diagram, (I left the lights out and also, I have no junction block) how does the alternator current get back to the battery, if, current flows [u:7317f45f3f]from [/u:7317f45f3f]the battery to the same post (+) on the ammeter.

in your wiring diagram, the current produced in the alternator simply flows from the wire marked batt on the alternator back to the battery. however your ampmeter wont show the current being produced, or discharged from the battery since its wired wrong. since the alternator puts out typicaly 14.5 or so volts current simply runs backwards so to speak..NOTE: add a ground wire to the negative side of your guage and this wiring diagram is basically for a VOLTMETER instead of a ampmeter, and it will work as intended. a voltmeter shows battery voltage,or voltage being produced. a ampmeter shows amps being produced and either directed back to or away from the battery. they are wired differently.

if he changes that ammeter to a voltmeter and adds a ground.. the voltmeter will be ALWAYS on... I'd want mine rn thru the ignition switch.. not always powered...

You guys...on one hand, these meters don't help much...but, I do want it wired to be like how it was stock...

So should I move the alternator wire to directly hook to the battery(I sense a huge shower of sparks)...I'm so bad at this stuff...

(quoted from post at 10:20:02 01/08/13) You guys...on one hand, these meters don't help much...but, I do want it wired to be like how it was stock...

So should I move the alternator wire to directly hook to the battery(I sense a huge shower of sparks)...I'm so bad at this stuff...

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rash your sketch & do it like this:

follow jmor's pictogram.

YOU DO want some kind of metering..

thats true, but some folks like them wired this way, i'm like you though ,i would prefer mine to shut down also. just trying to explain how they worked.

Wiring it your way will result in a short to ground.

actually ,a amp meter or voltmeter is very good diagnostic tool to have aboard.oftentimes you can diagnose everything in your electrical system with one. one comment on jmors diagram, you need to figure out what alternator your using also. this diagram is for a one wire alternator which is what you show basically in your sketch.

I have a 1 wire alt...

So back to what baffles me-given a single alt wire going to a junction block out of which comes a wire that runs to the ammeter + side, and then the - side goes to the solenoid, and from there, to the battery + side, if current flows from the alternator, and from the battery, how does that work? How does the battery charge if current flows out of the + battery post?

(quoted from post at 08:59:31 01/09/13) So back to what baffles me-given a single alt wire going to a junction block out of which comes a wire that runs to the ammeter + side, and then the - side goes to the solenoid, and from there, to the battery + side, if current flows from the alternator, and from the battery, how does that work? How does the battery charge if current flows out of the + battery post?

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ope you are not still looking at your first posted diagram. Don't. At least 3 conditions can exist here. 1)The alternator is doing nothing (belt broke), so the battery has to power all loads (ignition, lights....), so current (conventional) leaves + batt post, to ammeter (-), through ammeter (-) to (+) {running current through it in this direction makes it indicate a neg or discharge}, and on to & through the load & out opposite load terminal through chassis & back to battery neg(_) termimal, this completing the loop. 2) New belt on alternator, but battery is dead as a door-nail, so you use a jump box to start tractor. Alternator outputting current, flows to junction block, where the alternator current value splits, with some part supplying loads (ign, lights...) AND some part finding a path through the ammeter and on to the battery{current is passing through ammeter from (+) to (-)and on into battery(+) post {running current through it in this direction makes it indicate a positive or charge}. Thus the ammeter indicates the amount of battery charge current. On a dead or near dead battery, this will be large, but as battery nears full charge, the reading will trickle off to nearly zero. 3) As battery reaches full charge, the alternator will be providing current for the loads and the in/out battery current is virtually zero. So we have three cases, 1) battery supplying all loads, 2)alternator both charging battery & supplying all loads, and 3) battery loafing & alternator supplying all loads.

Good post. New battery. Alt belt definitely not broke. And I believe I had the alt tested last summer and it was fine...So is option 3 - battery loafs (it's a reserve power supply duh) and alt provides enough power to run everything...?


Very interesting, and a good learning exper. for me...thing is, new battery almost dead when I tried to start...hadn't run it in months, but the 'old' 'bad' battery almost always at least would give me a few good rumpas...so, makes me wonder if the last time I drove it, late summer, the alt was going and thus, I drained my new battery...will check on that. Thanks for the input.

Update-got er wired up - Yellow Alt, yellow IGN, red Ammeter(+) and wire to lights, all in one wire nut. Hit starter with key off and ammeter goes down. Pull light switch (I forget if I had key on or off) and ammeter goes up. Sound normal? (All those with motor not running).

Can I safely test my alternator, or do I have to take it to the parts store for a test?

Eric.........you ask......."Can I safely test my alternator, or do I have to take it to the parts store for a test?" taker to the store, tests are usually "free". ........Dell, 12V advocate for the right reasons

Typical for me. Go out to start the tractor, dead. Battery (new in summer) is dead. Hilarious.

Someone wanna offer why based on the fact that I wired it like the diagram?

Did you have that alternator tested? Bad alternator could drain your battery.
As to your question about the lights, no, that doesn't sound normal.
If you turn them on with the engine off the amp gauge should show discharge.

Haven't...I dont' use the tractor much, with the tiny snows lately in MI...Alt can drain a battery with key off?

This happened with key off...

(quoted from post at 17:16:09 01/12/13) Typical for me. Go out to start the tractor, dead. Battery (new in summer) is dead. Hilarious.

Someone wanna offer why based on the fact that I wired it like the diagram?

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)maybe you didn't wire it the way you think you did, 2)alternator bad, 3)left key or lights on when last used, 4) maybe battery not really dead....hydrometer?. Bad, dirty, loose connection can appear to be dead battery to some folks.

Take a look at the drawings again, alternator is hooked to the battery all the time. Key off.
I know what you're saying about the mild winters lately.
I'm only about 30 miles from you, just off M66 and M57 corner.
Shoot me an email if you want and maybe we can get together and figure it out.
Email is open on modern view.

I appreciate the offer. But this wiring scheme is embarrasingly simple. I simply took a wire nut (I have no resistor block) and wired the ign, lights, ammeter + side all together. The battery is a few months old. I had tightened the cables down good. I did notice tonight that I did wire the ammeter backward-looking at the meter + isn't the same as + in the back...duh. So that explains why my ammeter goes UP when I turnd on the lights.

What I'll do is take a meter to it with key off and see if I'm getting power to the coil. I have a sneaky that my new key circuit from farm store (not TSC) is letting current fly thru it all the time. It did seem to turn awful easy, despite it being new...should be a simple test.

You have "no resistor" on a front mount?

I have 2 inline because my coil had low resistance.