4020 Charging Voltage Problem

I own a 4020 (gas) with a 12V, positive ground system charged with a DC generator.

I am putting in a convenience outlet to power a baler monitor so I checked to make sure I was getting a good voltage across the battery during operation. The voltage accross the battery (or voltage regulator) bounces around between 0 and 18V and is very difficult to read. I don't know much about DC systems but this does not seem right and I doubt the monitor will work properly with this voltage. The tech manual says the voltage should be closer to 14-15V while charging.

Any thoughts. It looks to me like a regulator problem but I'm no expert so I'm looking for a second opinion before a start changing parts.

I would appreciate any help.

There is no way you are seeing 0-18 volts at the battery, I would expect it is your digital meter and a mechanical regulator If the lights look about right, would leave it at that.

Its possible its the meter. I checked another tractor (1020) with the same meter and it's steady at 14V with the engine running.

Since most if not ALL baler monitors are designed for NEGATIVE ground, be very careful of your polarity when hooking things up. Make certain EVERYTHING and I mean EVERYTHING about the baler monitor is ISOLATED from ground. Might be a good time to think about changing the 4020 to negative ground with an alternator. If the monitor happens to be a New Holland Bale Command system, I'm not sure the generator would produce enough current to run it.

When you say "The voltage across the battery (or voltage regulator) bounces around between 0 and 18V and is very difficult to read"

So which is it, the Voltage across the battery terminals orrrrrrrrrrr the Voltage Regulator, and if so, which terminals????

The voltage on the VR's BAT terminal with respect to frame ground should theoretically be about the same as across the battery subject to wiring and grounds and resistances and connections etc.

Since a battery is like a big electron bank and acts as a buffer and capacitor, ITS HARD TO MAINTAIN A FULL 18 VOLTS AT THE BATTERY. It takes a darn good charging system to get it to 14/15 ya know. Id expect more like 13.5 to 14.5 volts across a battery if coupled to a good working DC Generator system, certainly NOT 18 (Don't have a calf Billy Bob, all subject to RPM and battery state and genny and VR of course)

Also the quality and design and damping and response time of a meter makes a difference, Id be more apt to trust what my old Analog Simpson 260 Voltmeter says across the battery then a fancy schmancy digital meter

Also your tractor is most likely POS Ground so whats the polarity of the device youre adding???

John T

A solid state regulator will give you a pretty steady voltage, a mechanical regulator is basically on/off, the battery averages the voltage.

Your correct in that the monitor is a negative ground. I planned to go right to the battery with a 30 amp breaker. There is only a positive and a negative to the monitor so I didn"t really think the ground made much difference. However, you may have a point. I would assume the tractor and baler will be electrically connect thru the drawbar/pto. Seems like this could be a problem. Thoughts?