5000 regulator acting weird

[karl f]

I have to do some more diagnostics when I have time, but I find the issue interesting. I dug into it because the tractor didn't start in the field the other day due to a dead battery.
The battery had been charged after the no start. After filing and adjusting the regulator contacts, the warning lamp is working normally and the voltage at the battery is only 12.4 with the engine at 2000rpm. The cutout is closing and opening properly, I kept the cover off to inspect and observe.
The battery is over 5 years old, and had tested below rated output 2 years ago with a $500 midtronics tester--can a poor battery reduce the output of the B-circuit systems?
I plan on replacing the battery and diagnosing the low charging voltage soon. I've got the shop manual and the tools, so I'm ready although any insight into the low voltage would be appreciated.
thank you
karl f

 

[souNdguy]

if the battery has a bad cell, it may make it wher ethe reg/gen is UNABLE to make the voltage go any higher than the battery with the reduced cell count. this can overwork the genny.

what happens if you start the tractor, then put a car battery in it.. and rev up. what's votlage do?

will genny motor, etc?

 

[karl f]

Soundguy,
sounds like you're in my head. I have the same tests in mind.
I wonder if an A circuit generator would goto full charge in the same situation or not?

My dad's been busy making hay with it and my schedule isn't matching up with the tractor's lately so I hope we both get a day together soon. Our last date for electrical was interrupted by the baler needing a bearing. Mechanical failure is typically more urgent. As long as the tractor starts, it's gonna be gone.

thanks for your thoughts
-karl f

 

[sotxbill]

If you jumper 12 volts to the field terminal for just a moment, the generator will go to full charge. do not do this for more than a 20 seconds.. and you should see the voltage rise on the battery, or at least on the output lead of the generator. If the voltage rises, then the voltage regulator is probably still bad and need more work or replacing. if it rises at the rear of the generator output and not on the battery, check the wiring throught the regulator and down to the starter selonoid and then to the battery.

 

[souNdguy]

when output is low, reg shoulkd call for high charge. more or less leaving field points closed, jumping out field resistor. if the load of the battery is enough amps to dray the voltage still lower, charge amps will max out unless a current limiter is present in the regulator.

ont he other hand.. some bad bats charge up fast but have no capacity.. charge voltage is normal.. current is low.. reg doens't have much to do.. yet batter has no capacity.

i'd test static battery.. then specific gravity test it. if a cell is bad.. toss.. then get battery..full field her.. and motor test genny if you suspect no charge

soundguy

 

[JMOR]

(quoted from post at 11:01:09 07/17/12) Soundguy,
sounds like you're in my head. I have the same tests in mind.
I wonder if an A circuit generator would goto full charge in the same situation or not?

My dad's been busy making hay with it and my schedule isn't matching up with the tractor's lately so I hope we both get a day together soon. Our last date for electrical was interrupted by the baler needing a bearing. Mechanical failure is typically more urgent. As long as the tractor starts, it's gonna be gone.

thanks for your thoughts
-karl f

"I wonder if an A circuit generator would goto full charge in the same situation or not? " Just curious........why would you think A/B might make any difference?

 

[karl f]

(quoted from post at 06:43:56 07/18/12)........why would you think A/B might make any difference?

JMOR, I'm not sure what was going through my head when I asked.
-karl f

 

[karl f]

I did some tests this evening. All charging system wires and battery cables have near zero ohms resistance individually, so no broken or corroded wires. The generator will jump to 20+volts if full fielded. I need to get some alligator clips for my multi-meter or grow a couple more arms. I think I should have an analog meter in the future, but it is looking like the regulator is the culprit

thanks for the advice.
karl f