Alternator not charging battery. Alternator, battery, and fuses all check out fine.

[94BULLITT]

Do you have a starter alternator shop nearby? They could check the alternator, voltage regulator and battery for very little or maybe no charge.

 

[David Devuono]

Did you take the battery and alternator to the mechanic, or the whole tractor? If you took the individual parts and they checked okay I would check the wire from the Alternator to the battery. Like when you checked the fuses in the Ohms setting (200ohms setting?) with the positive battery cable removed, check from the battery connector to the terminal (one with big wire) on the Alternator. If that wire looks okay, then there may be another smaller wire to the alternator to excite the unit to produce voltage. Often this exciter circuit goes through a lamp on the dash panel. If that lamp burns out, the alternator wont charge. It would be nice to see a picture of the alternator back side. It would be at the front of the engine connected by a belt. If you don't have airconditioning, its likely the only thing using the fan belt. The exciter wire would connect via a small plug to the alternator (doubt you would have an external regulator?)With the battery connected, the meter set to 20Volt DC Volts setting, with the key in the position just before engaging starter, you should have 12 volts showing.

If your tractor is 5-6 years old, it would not hurt to buy a new battery. A diesel tractor should run for several hours with a fully charged battery. Newer tractors use a 12V selenoid to operate the fuel cut off (big click when starting) but otherwise do not need much electricity. I use my old MF135 all day with no battery when I forget my keys and have to start it with a screw driver at the starter selenoid.

 

[k0ua]

When I referenced the alternator "stud" I mean a threaded bolt connection on the back of the alternator that the large diameter wire hooks up to than a nut threads on to this stud to hold that large wire on to the alternator. This is the high current output of the alternator. The wire is usually red, but of course could be any color. I guess at this point we need to determine if you really do have an external voltage regulator or not..I was thinking that most newer tractors have had an internal to the alternator voltage regulator, but if yours does not, then that sure would be a suspect if it is not exciting the alternator and therefore the alternator is not producing any output. The only way to fix any problem is to stay with it.. The guy who charged you $280 and ran away, ought to have his butt kicked, and If I was there I would do that for you. The good news, when you get done with this you are going to know a lot more about vehicular charging systems then he does.

James K0UA

 

[MomNottaMechanic]

The guy who tested the alternator for me is the owner of an Alternator & Starter Shop in Jefferson City, MO. I talked to him again this morning and he said the voltage regulator is inside of the alternator and works fine. He specifically looked at it when he was testing the alternator as he knows my husband and knew I was on my own on this. So my hope that it was simply the voltage regulator are most likely shot. He is going to show me how he checked the alternator later today, but basically he hooked it up and made sure it could charge a battery there and then went through it piece by piece to check for any oddball problems such as the voltage regulator, wiring, etc.

I'm going to go finish up livestock chores and then play with this some more by figuring out the alternator stud thing, etc. Thank you for the further descriptions, James, as that helps me figure out what exactly I'm looking for. If that is not my problem and it is not a grounding issue for the battery, it's going to get interesting.

 

[94BULLITT]

Check the tractor running at fast idle at the battery and see how much voltage you have. If you don't have around 14.v check the stud on the back of the alt as James described. I doubt your ground cable is dirty because you did not say it is hard to get started.

 

[3v0]

I have been teaching my wife to be more self reliant and it is a good thing. I expect we could start a long lived thread on bad experiences with mechanics and garages.

You have had the alternator, regulator, and battery checked out by what sounds like reputable people. In my mind the #1 suspect is the wiring.

Start by looking at the battery cables. I know you cleaned the connection going to the battery but that is only part of the story. They may not be bad it is the place to start.

Clean the connections at the other end too, after disconnecting the battery. If either of these cables looks 'swelled' or has an iffy connection to the terminal on either end replace it. Bad battery cables can look good and you can't test their ability to carry current with an ohm meter. You can fake replacing the ground side by running a single jumper cable from the battery ground to a good/bare ground on the frame or engine.

Check the voltage at the alternator stud next. The alternator needs to have its field coils energized by the battery so an alternator that does not work on the tractor can still be a good alternator.

 

[Coyote machine]

This thread is going around in circles. You're getting the same or different advice from various people. Everyone means well, BUT I'd like to try to keep you from getting confused. First, instead of speculating about what it is or isn't, you need to eliminate the battery, and alternator first and foremost.
After that you can fool around with the alternator hot wire, exciter wire, etc.
I'm beginning to think the battery is not able to hold a charge due to itself alone. Even though it's relatively 'new', batteries CAN and DO fail for a variety of reasons, and may take a charge up to nominal state of 12.++ BUT when they face a load like running the tractor with the headlights on then they can drop right off to next to nothing, even if the alternator is putting out the proper charge, though this is less likely in this situation. So get your friends battery and let's see what happens with it installed.
And as far as people telling you that cleaning the ground cable at the frame is only related to no start conditions, that is often the case, BUT not always. Sometimes a dead battery ground cable will not allow the charging system to function, and mask itself as the real problem. I've seen this before at times when I had my foreign auto shop. I've especially seen it with boats in salt water.
When you get the replacement battery and you get her running take the ground cable with a gloved hand and wiggle it around and see if it has any effect on the voltage coming back to the battery. If it fluctuates at all of jumps up and down than at least one issue- a bad ground cable has been found and it needs to be replaced for certain.
Don't worry for now about the alternator bolt or anything else for that matter.
You could ask the person who tested the battery if he did a 'load' test on it and how it performed. If they did NOT do a load test then they really can't say whether it is good or bad.
BTW, You're welcome for the caution on the acid- don't want you to compound your issues with unnecessary additional problems.
No one here is thinking your husband is a slacker- we're thinking you're a good wife to him!:thumbsup:
The idea about using a jumper cable to bypass the existing ground cable may come in handy, so let's keep it in mind for later.
Oh yeah, and the $280 guy deserves a turnaround of fortune...what a jerk.....
Post back.

 

[uglyboywith11fingers]

wow... a lot of advise from well-meaning folk, but it seems not everybody is reading what the OP has already done...
1. New battery last fall and just tested. When fully charged, it is good enough to start the tractor, so I wouldn't suspect a problem with battery cables at either end. It bothers me that the battery voltage goes down so rapidly after the tractor is started... should last for hours, the only load should be the fuel pump ?
2. Alternator has been tested off the tractor. Wiring to the alternator that must have been removed, likely consists of a plastic plug with 2 or 3 wires, and one larger wire fastened to a stud, probably under a rubber boot. That is the alternator stud referred to earlier, where approx. 14volts should be measured with the tractor running. I`d suspect the wiring from the alternator, but that could be a bugger to sort out without a detailed wiring diagram.
Hope I didn`t muddy the waters for the OP.

Pete

(does the TYM use a Kubota engine & alternator)

 

[Coyote machine]

Unless a LOAD test was run on the battery it's age and someone saying it is OK is NOT what it's showing in real life. If it was able to take a full charge and HOLD that charge, it would NOT drop for 12.6V down to 11.xx Volts in 3 minutes. I suspect the battery is a goner as a result of a loose or broken wire in the charging system that has caused the tractor to run on ONLY battery output. This has 'deep cycled' a 'charging' battery that is not designed for deep cycling, and though it is still able to take a charge up to nominal 12.6 Volts, when on an external charger, it can no longer sustain repeated charging and discharging, and consequently it ends up dropping the 12.6 to 11.xx and then it's dead.
For the record, I've read every post on this thread several times, and the ONLY way this tractor is going to get fixed is by using a systematic approach, and eliminating one item at a time ON the actual tractor. Starting with the battery and then going to the alternator is the way to go. By eliminating the battery and replacing it with another know to be good one we will see if the charging system output stays the same or puts voltage back to the new battery at higher than it's state of charge when installed. If it does- problem solved- battery junk. If it does not, then charging system and or it's wiring is suspect. One step at a time.

 

[HarryN]

wow... a lot of advise from well-meaning folk, but it seems not everybody is reading what the OP has already done...
1. New battery last fall and just tested. When fully charged, it is good enough to start the tractor, so I wouldn't suspect a problem with battery cables at either end. It bothers me that the battery voltage goes down so rapidly after the tractor is started... should last for hours, the only load should be the fuel pump ?

She never started the tractor with the battery she said "I am having to jump the battery on the tractor each time to get it to start"