# Undercharging GT5000 battery, why?



## speeed001 (May 10, 2017)

Hello, all. I'm having a charging issue on my 2003ish GT5000 and I was hoping someone here could help. When running, the dash-mounted ammeter shows a slight discharge when running at full throttle, and an even greater discharge under PTO. After an hour or so of mowing, I don't have enough juice left in the battery to restart the mower, and I'm also having an issue with the PTO clutch disengaging, which I believe is also related to lack of voltage. 

I tested the alternator and regulator, and found that the regulator was only putting out a little over 12 volts, so I replaced the regulator. Turns out, the brand new regulator is only registering a little over 12 volts also. So I'm guessing the problem must be somewhere else.

Here's what I've checked so far:


Voltage at battery (off): 12.5v
Voltage at battery (running): 12.4v
Voltage at battery (running, PTO engaged): 12.3v
Voltage at *new* regulator - between red lead coming out of regulator and frame ground (running): 12.4v
Voltage out of alternator between two yellow leads, with regulator disconnected (running): 28-29 volts. Within spec.
Added a ground jumper wire from regulator mounting bolt to nearby frame.

I've checked for continuity between the jumper ground and the negative battery terminal, as well as between the red regulator lead and the positive battery terminal, both show continuity. 

I'm still not getting the 14-ish volts to the battery that I should be getting from this regulator. Anyone got any suggestions? Thanks!


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## RM-MN (Sep 11, 2015)

I'd be guessing that you got a bad new regulator. It happens fairly often. The other choices are a bad contact on the battery (not likely if it starts the engine when charged), or a bad alternator. Can you check the output of the alternator to make sure it is putting out charge. If it is, you have a bad regulator or have it wired incorrectly.


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## speeed001 (May 10, 2017)

Alternator is putting out the factory-specified voltage, I think it was 28-29 volts. I'll be bummed if I got a bad regulator right out of the box. Is there a way to test a regulator off the tractor? What would happen if I connected it to 120v AC at home... could I test it that way?


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## sixbales (May 18, 2011)

Howdy speed001, welcome to the forum.

I would not put 120VAC on it. Check all connectors in the charging circuit for burned or corroded contacts. If you find any burned connector terminals put a short jumper wire around the connector for the faulty connector terminal. I have done this on my Kubota G1900 riding mower on several occasions. I use small wire nuts for the jumper connections so they can be disassembled in future.


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## Bill Kapaun (May 8, 2007)

Is the VR grounded to the engine block?


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## wjjones (May 28, 2010)

The underside of your flywheel will accumulate dirt/ debris over time which can affect the stator, and magnets under there. I just cleaned one yesterday it was so bad the magnets where barely visible. Have you also checked all of your connections, grounds, etc?


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