JD Z520a - electrical system issues

[fxvinyl]

I have a Z520A, and what i thought was a dying battery has actually turned out to be a more difficult problem to solve. The symptoms are that if I put a fully charged, new battery in the mower, it starts and runs fine. But within a few hours, the hydraulic deck control starts not working, and eventually the mower deck shuts off and will restart and rub only for a second or two. Finally, if I shut the engine down, I have to jump it to restart it.

So this must be either the charging system or maybe the voltage regulator? But I have no idea really where to start in terms of narrowing the source of the problem and any help would be appreciated.

Oh, by the way when I run the diagnostic i get 3-2, "low voltage condition".

Any guidance on how to definitively diagnose & repair this would be great, esp as my nearest dealer just closed up shop.

Thanks,

billy

 

[beenthere]

Do you have the service tech manual for your Z ?

John Deere Technical Service Manual on CD - TM11219CD

 

[fxvinyl]

No, unfortunately. I guess I could order that (thanks for the link), but wonder if the info is available online somewhere?

Do you have the service tech manual for your Z ?

 

[Richard001]

Billy,

First thing you need to do is find out if your charging system is working. If you don’t have a voltmeter, get one. Don’t buy the cheapest thing you can find. It should be able to measure volts, both AC and DC, resistance and would also be good to be able to measure current up to say 10Amps.

Check the battery after you have charged it up.

There is always some residual charge on a battery after being charged. Wait an hour after charging it to measure the voltage.

A fully charged cell at 80 degrees F would show a specific gravity of 1.265. If all six cells are fully charged, an accurate digital voltmeter reading of battery voltage would show 12.68 volts.

After you have determined that the battery is fully charged, hook up it up to the machine. Start the motor, then measure the voltage at the battery terminals. With the engine at idle, you should see just the battery voltage. Then speed up the engine to about mid-speed. The battery voltage should raise to about 14V DC. This would indicate that the charging system is working. If you do not see a raise in battery voltage with increased engine RPM, then your charging system is not working.

From you description, it sounds like this is the problem you have. If this is the case, then report back.

The next thing would be to check the AC output voltage from the charging coil.

Richard

 

[fxvinyl]

Thanks Richard. Yup, seems there's a charging system fault. I measured the voltage as indicated with a good quality digital voltmeter, and nada change at all when the RPM went up. I took the liberty of doing some digging on available service info for the Kohler engine I have in this machine, and decided to take a chance on swapping out the regulator since it is relatively easy to get to and a cheap part that could be the culprit. If not, it seems the other possible culprits may be more involved/expensive to replace?

I can report back when I replace that part with any findings.

Thanks again.

Billy,

First thing you need to do is find out if your charging system is working. If you don稚 have a voltmeter, get one. Don稚 buy the cheapest thing you can find. It should be able to measure volts, both AC and DC, resistance and would also be good to be able to measure current up to say 10Amps.

Check the battery after you have charged it up.

There is always some residual charge on a battery after being charged. Wait an hour after charging it to measure the voltage.

A fully charged cell at 80 degrees F would show a specific gravity of 1.265. If all six cells are fully charged, an accurate digital voltmeter reading of battery voltage would show 12.68 volts.

After you have determined that the battery is fully charged, hook up it up to the machine. Start the motor, then measure the voltage at the battery terminals. With the engine at idle, you should see just the battery voltage. Then speed up the engine to about mid-speed. The battery voltage should raise to about 14V DC. This would indicate that the charging system is working. If you do not see a raise in battery voltage with increased engine RPM, then your charging system is not working.

From you description, it sounds like this is the problem you have. If this is the case, then report back.

The next thing would be to check the AC output voltage from the charging coil.

Richard