Green Tractor Talk banner

455 GT Overcharges Battery

7239 Views 9 Replies 5 Participants Last post by  Manomet
I have two 455's and they both overcharge the battery. When I start either tractor, the voltage is around 14 volts and then gradually increases to around 15.5 or higher. I tried a voltage regulator off a 425 and it had the same result. Both tractors are in the -040000 serial number range and have the 20 Amp Denso alternator.

So...... I checked JD Parts and they show the AM126304 Voltage Regulator is a substitute for M97348. See DTAC Solution 46546. Does anyone have access to this DTAC Solution?

My SWAG is that the AM126304 is the solution to the problem. but I don't want to spend $70 if I am not sure.

1 - 5 of 10 Posts
Thanks Kevin,

I bought my first 455 for $671. It had sat outside for a couple years. I had to clean EVERY electrical connection on the tractor. SO, yes I cleaned the battery cables at both ends. The tractor had a new battery and was load tested. I checked my second 455 after I bought it and discovered the same problem.

I own a 322 and 332 GT with Yanmar engines and the same alternator as the 455's. These models had a problem with the batteries being overcharged. I isolated the problem to be that there was a voltage drop on the sensing lead (Green Wire) to the VR. I added a relay to connect the VR sensing lead directly to the battery and the problem was eliminated. Later I discovered that this was also John Deeres's solution.

I originally thought that the 455's problem was the sensing lead. After testing the charging circuit, I discovered that was not the problem. The 322 and 332 would boil the battery, but the 455's do not seem to be as bad. I have just ran them and they seem to be O.K. Looks like a winter project to attempt to resolve the issue.

See less See more

The strange thing is the voltage is lower when the tractor is started and gradually INCREASES. Normally the voltage is higher when the tractor starts to recharge the battery and then reduces as the battery is charged. :confused:

I have a Tektronix TEKDMM155 which is a very good meter, but I also tried my Fluke. Never assume anything when trouble shooting. It is strange that two tractors and three voltage regulators have the same result?? I will figure this out!! :dunno: It is just a matter of time and money. Since I am retired, I have plenty time, but little money.

I was checking my air filter and noticed that the battery was wet on top. Overcharging was my verdict.
Well I did more troubleshooting and found that the problem was a voltage drop on the VR sensing lead. This is the same as my 332 so it will be a simple fix.

I added the relay kit to my 455's and it reduced the charging voltage about 1.2 volts. I have ordered two voltmeter gauges which I will be adding to both tractors. In the future, I will be able to continually monitor the charging voltage. Yes, I will document this installation with pictures in the near future.

1 - 5 of 10 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.