High current draw with key on

[Lcarter]

Need help
I have a 12 year old ZD21, it's been great. Today the battery was dead. Cleaned the battery post made sure the cables were clean and tight. Jumped it off with cables. Once it was running I checked the voltage at the battery to make sure it was being charged. The voltage was 30 volts. I moved it back to the shead and it cut off by itself. I attempted to start it it would not turn over. The battery shows 13.2 volts with the key off. When the key is on, the battery discharges rapidly ie 30 sec and the voltage is down to 10 volts. Turn the key off and the voltage comes back up on the battery.any sugestions

 

[kuboman]

Sounds like maybe your glow plugs are stuck on. Turn the key on and check the voltage to the glow plugs. Im betting you will show voltage.
Also you should not show 30 volts. It should not be more than 15 so maybe your voltage regulator is pooched.

 

[Stubbyie]

How old is the battery? Battery voltage sounds goofy. Disconnect completely from machine and try charging to known full charge, maybe overnight. Disconnect from charger and check voltage. Just from grins get an old headlight and using jumpers from the battery energize the light while measuring voltage. If you see much of a dip, try a different battery. In so doing confirm the chassis ground connection is clean and tight.

When known good battery back on machine---note sparks when hooking up if you have a high-amp draw with key 'off'---leave key off and feel glow plugs (another poster here recently suggested using an infrared handheld pistol-type thermometer). If GPs hot you may have found the problem. If cold then cycle the key and feel or measure the GPs for function.

Here's a thought: I had a GP relay hung 'on' with key 'on'--the relay with built-in timer never would cycle 'off'. Result was that the machine could never charge the battery enough to keep up with the electrical demand of the GPs. Result: battery constantly 'low' but no suspicious current demands with key 'off'. I finally traced the problem back to the only component it could reasonably be, then started bypassing and changing components. If you have separate relay and timer components (or something else similar) try changing only one 'thing' at the time to see if problem resolves without buying everything new.

Could easily have a high-resistance short somewhere else. You just have too keep looking for bad wiring and / or switches.

If GPs hot with key 'off' start looking for a bad relay and / or timer. You need a parts book and perhaps a wiring diagram.

Please post back and advise how you proceed so we all learn.

 

[Lcarter]

First thanks for all of the suggestions. I unpluged and repluged all of the components that had quick connections. I removed the ignition switch, cleaned the switch and reinstalled. Then I fixed the real problem. I replaced the battery. After all of the above the charging system is working, the mower starts and there is no longer any high amps. Thanks again

 

[kuboman]

Battery's are the dangest things when they fail. I swear they engineer them to fail in a new way every year.