3 wire alternator nightmare

[Coaldust]

So, since the rotor is magnetized, there isn’t much stopping the unit from charging. Maybe the diode trio accidentally got zapped? Maybe the B+ wire shorted out to something? Maybe the B+ wire has a bad connection?

 

[frickenbored]

Well...I am the lord of the idiots. So when I replaced the v belt I replaced it with one of those Accu-link belts so I wouldn't have to pull the radiator, drain the hydraulic system, and unbolt the hydraulic pump from the crankshaft. Well those accu-link belts stretch a lot so I've been taking links out every time I run the machine. This time I noticed I could turn the alternator pulley by hand with the belt tensioned. Turns out I was trying to use a 3/8" pully with a 1/2" belt. So I swapped on the old pulley and pulled a few more links out of the belt and got it tensioned nice and tight. I started the machine and could see that the alternator was spinning faster.

But it still wasn't charging and the idiot light was lit up bright red. I unhooked the light and jumped the terminals together and that was it. It's now charging at 13.8V

I even hooked up one of my new led headlights and the voltage didn't drop. I'm just gonna eliminate that dummy light since this machine is turned off with a manual fuel shut off so I really don't care about back feeding on that circuit. Now I get to clean up all this wiring and install everything for good.

 

[Truck Shop]

Something was learned today.

 

[kshansen]

I was just checking the way I have the 10SI Delco Alternator on my 1947 Farmall BN.

On mine the "Batt" terminal goes right to the "AMP" gauge then the other side of the "AMP" gauge goes to the "POS" terminal of the battery. Both spade terminals (#1 and #2) go to one side of a pressure switch and the other side of this pressure switch is connected to the "POS" terminal on the starter switch. Think I used a simple 10#(or maybe even lower) pressure switch. No idiot light in the circuit.

It's been hooked up like that for something like 30 year, maybe more and is only on the second battery since I converted to 12 volts. And it was a used alternator, think it came off a old Chevy we scrapped at the quarry, when I did the conversion!

This is a newer version of the switch I used:

 

[Coaldust]

Those Hobbs switches were used back in the day to open the circuit. It’s a feature of the creature, in the SI family, to have a 10-15 milliamp parasitic drain.

 

[frickenbored]

Got all of my permanent wiring in, installed my new headlights and used the ol girl today to pull some stumps out of ground and everything seems to be working just fine. My amp meter reads right around 10 amps or lower most of the time and those $20 Chinesium led lights draw almost nothing.

I hooked up my voltmeter to the battery to watch the voltage...its not like a car where you get 14v instantly, I get a slow ramp up from 12.5V to 13.8V (im sure my junk batteries arent doing me any favors) but hey it's charging so I'm happy.

I have an empty gauge hole so I think I'm also gonna add a volt meter just because that's what I'm more used to reading.

 

[Camshawn]

I bought a current shunt and remote meter from Amazon for about $50 can. for our camper battery. Gives both voltage and current and I only ran small wire to the meter. Cam