Battery not charging

[Denna]

Regarding a 1976 Massey Ferguson 245 Diesel.

The following has been replaced:

... Battery (car battery from Walmart, not a deep cycle tractor battery)
... Battery to starter cable (from YT)
... Starter (from YT)
... Alternator (from NAPA)

When the battery is fully charged, the tractor will start and run correctly.

Over the course of 3 hours of running the tractor, the tractor can be shut off and restarted twice.

On the third start, the battery will not have enough charge to start the tractor though the gauges will move.

Multiple battery replacements have not solved this issue.

A short or parasitic drain is probably not the cause because if the alternator was charging the battery over 3 hours, the battery should end up with the same charge it started with.

Short of removing the alternator and having it tested, how can you verify if the alternator is charging the battery ?

The only things that haven't been replaced are the ground battery cable and wiring from the alternator to the starter. I haven't found any store that sells the wire harness that connects the alternator to the starter. Is there a place to find them or are you expected to make your own from bulk cable ? One of the wires looks like it has a Molex connector and I don't know where to get that part if it had to be homemade.

Any ideas or should the alternator be removed and tested ?

 

[Jim.ME]

(quoted from post at 13:59:55 02/05/23) Regarding a 1976 Massey Ferguson 245 Diesel.

The following has been replaced:

... Battery (car battery from Walmart, not a deep cycle tractor battery)
... Battery to starter cable (from YT)
... Starter (from YT)
... Alternator (from NAPA)

When the battery is fully charged, the tractor will start and run correctly.

Over the course of 3 hours of running the tractor, the tractor can be shut off and restarted twice.

On the third start, the battery will not have enough charge to start the tractor though the gauges will move.

Multiple battery replacements have not solved this issue.

A short or parasitic drain is probably not the cause because if the alternator was charging the battery over 3 hours, the battery should end up with the same charge it started with.

Short of removing the alternator and having it tested, how can you verify if the alternator is charging the battery ?

The only things that haven't been replaced are the ground battery cable and wiring from the alternator to the starter. I haven't found any store that sells the wire harness that connects the alternator to the starter. Is there a place to find them or are you expected to make your own from bulk cable ? One of the wires looks like it has a Molex connector and I don't know where to get that part if it had to be homemade.

Any ideas or should the alternator be removed and tested ?

What alternator do you have? Internal or external regulator? Do you have an ammeter or a charge indicator light? do you have a voltmeter/multimeter you can test with? How about a picture of the wiring on your alternator?

A tractor battery is the same type as a car battery, it is not deep cycle. A high cold cranking amps (CCA) rating for the size that will fit in is always best.

 

[used red MN]

A voltage reading across the battery terminals is what you need to do. If you do not have a multimeter you can get one for $20 - 25 at an auto parts store, hardware or home improvement store. You are looking for a 13 to 14 volt reading while the tractor is running. This includes with any lights on, although with the lights on the engine may need to be sped up to a 1000rpm to maintain the voltage. Although it would be wise to have a heavier duty battery for better starting and less stress on the starter I do not believe the battery is causing your problem. Unless of course you are trying to start the machine after it set outside in a temp of 15F or below.

 

[MF#1]

I searched your history on this tractor from 2017 onward and I have to say something is amiss in your wiring. You've had several issues before: running out of fuel, no starts, alternator issues, neutral safety switch problems, starter problems, etc. One time you jiggled some wires and it started. That is what leads me to believe that the wiring is somehow not up to par. If you have the alternator tested I would guess that it will be good, assuming there were no sparks or other things happened when you installed it. If you lose the battery in 3 hours then you have a serious short/bad connection somewhere or a bad battery. The Operators Manual that you have has a good wiring diagram that shows the color of the wires and sometimes the size/gauge. THAT would be my starting point, focusing on the charging circuit. There is ALSO an oil pressure SWITCH behind the dash that allows the alternator to start charging AFTER the engine is running. ANY wiring shortfalls in that circuit WILL prevent charging, period. In an earlier post a few years ago Dieseltech mentioned the diode built into the charging circuit, another possible charging problem. I want you to know that I'm NOT trying to bring you down or get upset, I would REALLY like to hear that you got the bugs out of it. Good Luck and keep at it!

 

[Denna]

Jim.ME,

 

[2tractors]

Usually when there's a power drain you can disconnect a battery cable then touch it to the same post and if it sparks it indicates a short.

 

[Jim.ME]

That appears to be a Delco type 3 wire alternator.

Do you have battery voltage all the time on the BAT terminal of the alternator? That wire should run to the load terminal of your ammeter. (You didn't answer as to whether you have an ammeter, but I think your tractor does.)

Do you have voltage on the #1 wire in the plug-in connector when the engine is running? #1 wire provides power to excite the alternator and start it charging. I think your tractor originally had an oil pressure switch to control this power. If it is still working #1 should have power whenever there is engine oil pressure.

Do you have voltage on the #2 wire in the plug-in terminal? This can be all the time or just when the engine is running depending on where the other end of that wire is attached. #2 wire senses system voltage and gives feed back to the regulator.

Do you have voltage on both terminals of your ammeter at all times?

The battery you show should work fine.