Battery Charging Issue

[militiaman11]

Hello. I have a 1961 IH 340 Utility. Posted about it a few times on here now. I'm currently experiencing strange behavior with the battery not charging and i wonder if anyone can shed light on this. the battery is brand new, and i have recently had the alternator tested. it checked out fine by the auto parts store, but i don't know if that can fully be trusted. recently i had the alternator off to change the belt and do some other things, and when i put it all back together the battery was charging fine. measured over 14V on the battery while the tractor was running. now, mysteriously, without changes the battery sits just at 12V while the tractor is running. if i measure voltage directly on the alternator i am getting 15V while running, but at the battery i'm getting 12V. One question i have here is that the wiring diagram in the manual shows a positive ground. This tractor was converted to an alternator, and has had some wiring hacks done over the years by previous owners. but should the tractor still be positive ground? it is currently a negative ground, and has been since i purchased it. i have checked all connections and they all seem clean and tight, but the lack of charging suggests to me a loose or broken wire. or maybe the alternator is now failing. any help would be great. Thank you ahead of time.

 

[used red MN]

For one DO NOT change it to positive ground you will directly let those hard working smoke worms out of your alternator or the wiring. Does It have an ammeter? Could be possible that the wiring has a failed connection. Does it have a one wire alternator or a 3 wire? To temporarily check the wiring run one of the leads from a set of jumper cables from the alternator terminal to the positive battery cable terminal. Start it and then measure battery voltage if it is up to the 15 volts then your wiring has a problem.

 

[Janicholson]

When the tractor is off, there should be battery voltage at the big terminal of the alternator. if none, there is a disconnect from that terminal to the battery. it could be a failed amp gauge or if none, a wire broken inside. do some tracing with a test light. If it has only one wire on that big terminal on the alternator, it is likely a one wire alternator. it should work that way. If there are 3 wires (two on the edge, and one on the big terminal, it should have measured 12+ volts on the #1 spade terminal in that side connection, and the #2 terminal should be connected to the big post on the alternator a few inches away. Jim

 

[Russ from MN]

You need to troubleshoot, start at the alternator with your voltmeter, with the engine running. Follow the wires towards the battery, checking every connection. When you find a significant drop in voltage you have found the problem.

 

[BarnyardEngineering]

If you're getting 15V at the alternator's big bolt terminal, usually labeled BAT, then it is working.

That particular part of the wiring in an alternator conversion is very simple. There should be a 10ga wire running from that BAT terminal on the alternator to one post on the Ammeter (the same terminal with the wires that run to the ignition switch and lights). Then from the other post on the Ammeter to the battery terminal on the starter solenoid (should be the ONLY connection on that side of the ammeter).

 

[Red Dave]

Sometimes these slow turning tractor motors don't spin some alternators fast enough to get them started charging. You may be able to start the alternator by going to wide open throttle for a moment, or a better solution would be to put a smaller pulley on the alternator drive shaft.

This is especially a problem with one wire alternators.

 

[crsutton81]

My guess would be that there's an intermittent connection somewhere or assuming this is a 1 wire alternator, the regulator in the alternator is starting to fail. I have also had an instance where adding a ground wire to the rear of a 1 wire alternator case fixed the hit and miss problem of it charging. There was a poor ground through the mounting brackets.

 

[Brownie450]

If you are using a digital meter to read
Volts around the alternator, the readings
may be skewed somewhat by the internal
regulator providing hash. An analog
meter would be better in this position.
Jim

 

[560Dennis]

Had poor ground or cables give me issues. On the C was the control box to the frame was ( bolts)oxidized.