Charging sometimes.

[Strodad]

I have a 1990 L2850 with charging issues that are inconsistent. I have opened up the regulator and found nothing wrong, so I cleaned the contacts and everything seemed right again. A week later I am back to jump starting the battery. The alternator had been replace a month or so before I bought it and it appears to be new. I replaced the belt since it was the wrong size with the idea that a loose belt was the issue, but that is not the case. At an idle with the regulator wires disconnected from the alternator I read an average of 4 volts coming off of the hot post on the alternator with no real increase at the battery.
I am looking for a place to take the alternator too to get it checked since my local Kubota will not check it off of the machine.
I was looking at someone's post with links for amp gages that where digital combo gages and I wonder how environmental those gages are?

 

[Russell King]

You should be able to get the alternator tested at an auto parts store or a local alternator repair shop.

On the concerns about the gauges, the may be rated with an IP(environment protection) number. I recall that IP55 is good for exterior use but look that system up if the state that number style to be sure what you want.

 

[BruceP]

I am not convinced your problem is 'not charging'.

Disconnecting the wires while engine running is a good way to fry a perfectly good alternator. Without a load, the diodes and regulator may overvolt.

A battery is only a storage-device. It will go bad quickly if it is not kept FULLY charged.

A battery behaves very much like a bucket of water with these characteristics:

1. If you keep the bucket full and always top it up after using some water (starting the engine)...it will last for many years.
2. If you keep the bucket nearly empty, a hole will appear and keep getting larger (over months) until it will not even hold water any longer. (even if you fill it up... it will self-drain)

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FIRST: You need to COMPLETELY CHARGE the battery using quality battery charger at least 6 hours. Even a good alternator is not designed to charge a weak battery.

NEXT: A quick test is check voltage at battery terminals with engine at operating RPM. (expect around 13.8v)

Have you considered DISCONNECTING the battery whilst parked to eliminate the possibility of parasitic drain?

Let us know the status after you have done these things.

 

[Dave_eng]

Perhaps I am wrong but it seems to me that your testing is not following the WSM test procedures.

In case you do not have access to the proper charging system test procedures, I have attached the 9 pages from the WSM.

Electrical system troubleshooting needs a structured, disciplined approach to avoid endless parts replacement which bis what happens if the diagnosis is not being done properly..

Dealers are not equipped to test alternators and regulators off the tractor. In fact it is far easier to do the testing on the tractor as issues like poor connections or poor grounds show up where on the bench they are invisible.

If there are tests you do not understand just ask.

DENSO, a world wide manufacturer of charging system components, publishes a generic test procedure which many who have the discipline to follow each step have found useful. I have attached it for your reading.

Dave