I think what you are asking, is how to wire up your bale monitor to get 12 volts. 


( with two 6 volts batteries) You need to hook your ground wire to the right hand side battery(looking at tractor from the rear) BUT you need to hook you 12 volt POSITIVE wire to the left hand battery (by the starter)


Now, you could just run the baler monitor wires, over to the starter, itself; then hook positive to starter solenoid post; then hook negative to one of the mounting bolts of the starter(clean that surface up a little first, wire brush it) = 12 volts    

(6volt-series.jpg)

(6-Volt-Batteries-in-Series.jpg)

batterywiringdiagram.htm (2KB - 766 downloads)

6volt-series.jpg (7KB - 685 downloads)

6-Volt-Batteries-in-Series.jpg (20KB - 667 downloads)

This is two 12 volt batteries, in PARALLEL look like (just so you know)

(2-12 volt-parallel.jpg)

2-12 volt-parallel.jpg (5KB - 666 downloads)