Battery or generator?

1010 Blues · Nov 17, 2013

Generator indicator light will not go off. A new battery is $90 and it will take a charge, just want hold a charge. Here is the thing that I need help with, if the tractor is running and I pull the positive cable off the battery and the tractor shuts down, what does that tell me? I have polarized the gen and I am getting voltage reading from both terminals on the gen. I am out of my area of expertise on this guys, help anyone?

JMOR · Nov 17, 2013

As with all things, there is more than one possibility, but a good first shot is that the cut out in the VR is not closing. With it running at moderate speed, jumper between the VR's BATT and ARM terminals & see if light goes out & charging begins.

1010 Blues · Nov 17, 2013

Ok I will do that. I had the VR and Gen in a local shop and
they said everything checked out with both but that may have
been off the radar. Thanks.

Anonymous-0 · Nov 17, 2013

By the way, if the volt meter gives me variable readings
depending on the tractors RPM's does that indicate the gen is
working? One lead on the ARM term and one grounded. Any
thoughts?

John T · Nov 17, 2013

If its a DC Generator and Voltage Regulator System instead of an Alternator, my Troubleshooting Procedure linked below will help troubleshoot it and determine if non charging is the fault of the Genny or the VR. In Para 5 it tells how to full field the genny (ground the genny FLD post) and effectively by pass any VR problems to see if the genny is okay.

After it was returned from the shop did you POLARIZE the Genny?? Try that first (see my procedure) cuz if the genny is polarized opposite from the tractor, you can trash the VR

The shop may have polarized it opposite from your tractor???

John T
John Ts Troubleshooting

1010 Blues · Nov 17, 2013

Yes I did polarize the Ginny. I think it is just the weak battery. But I will be sick if I spend $90 on a new battery and the generator light is still on.

John B. · Nov 17, 2013

Ok for starters. Disconnecting the battery when the engine is running is a very bad way to check and see if a generator or alternator is charging. This causes the charging system to build voltage. If anything is turned on it can blow all the lite bulbs or gauges. Easiest way to check a generator is putting out is to take a test light and connect it to the power side of the battery (not ground) and touch the light to the "A" terminal on the generator with it running at 3/4 to full speed. If the light stays off the generator is working. If it lights up the generator is not working. All the ground connections on the generator to mounting bracket, bracket to frame, Voltage regulator to frame all need to be clean with a good connection. Any of these that are not making a good connection will cause it not to charge. You can use the test light in the same manner at the VR "BAT" terminal. These are just some minor tests for beginners but it will isolate your problem. IF you have had both the regulator and generator checked out and tested good proceed up to your amp meter for good connections until it connects to the battery cable.

old · Nov 17, 2013

Pulling a battery cable to check for a system charging is a good way to smoke test parts and on some system they can even kill you. NEVER do that!!!!
Only way to check the charging system is to use a volt meter. Check voltage with engine not running then check with it running. Not running you should get around 12.3 volts and running you should get around 13-14 volts. If when running you get say 10-11 volts your charging system is not working

LarrySTN · Nov 17, 2013

If your gen light stays on, changing the battery will not correct the problem. Read John T generator test, and you shouldn"t have trouble finding the trouble with your charging system.

John T · Nov 17, 2013

Hey I would be also, that's why I suggest you troubleshoot the charging system first before purchasing a new battery. Also if in doubt have a shop load test the battery for free......

Good luck

John T

1010 Blues · Nov 18, 2013

Yes today I had the NAPA guy suggest we do that.

36 Coupe · Nov 19, 2013

If that works the cut out has an open shunt coil.I always took the cover off the regulator to see if the cut out point were open.If closing them by hand starts changing the shunt coil is open.The generator will charge until the engine stops but wont charge when the engine is restarted.I find that new regulators have to be adjusted to get the proper charge rate.Thats why there are so many complaints about new regulators being junk.I had a 6v regulator that had a knob on the cover for adjusting the charge rate.I use an induction ammeter to check the charge rate on red light cars and tractors.Ive had these meters since the mid 50s.Told one poster where he could buy an induction ammeter for 8 bucks.He didnt like the 25.00 minimum order and didnt want to pay shipping.

JMOR · Nov 19, 2013

Perfectly good plan, 36coupe........at least for you & me, but.........how many of those readers would touch the can to internals & make arcs & sparks? As I have heard, screwdrivers should require a license, or at least remove a battery cable!

Battery or generator?

1010 Blues

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