Last year I bought a 1978 John Deere 4640. Tractor runs good and electronics work fine (ie radio, lights, gauges EXCEPT Voltage Gauge which has never worked). The issue is the batteries are losing charge, disclaimer: I do not know my electronics.
Now, this is where I get confused. There are 2, John Deere Strongbox 5D 6-Volt Batteries in the tractor. They are linked in a series, thus I would think putting 12 volts to the starter. But when I check the voltage going to the starter, it is 24 volts. Does this make any sense? How does (2) 6-volt batteries in series produce 24 volts on a voltage meter?
When the tractor is running, we checked the voltage coming off the alternator which shows voltage of 24+. I have read some articles about John Deere's having 24 volts systems but have not found anything regarding JD4640 having a 24 volt, and in fact the tractor specs I have found shows that JD4640 should have a 12 volt system (2, 6-volt batteries).
AM I missing something or does this make sense that 24 volts are coming off (2) 6-volt batteries.
Now, this is where I get confused. There are 2, John Deere Strongbox 5D 6-Volt Batteries in the tractor. They are linked in a series, thus I would think putting 12 volts to the starter. But when I check the voltage going to the starter, it is 24 volts. Does this make any sense? How does (2) 6-volt batteries in series produce 24 volts on a voltage meter?
When the tractor is running, we checked the voltage coming off the alternator which shows voltage of 24+. I have read some articles about John Deere's having 24 volts systems but have not found anything regarding JD4640 having a 24 volt, and in fact the tractor specs I have found shows that JD4640 should have a 12 volt system (2, 6-volt batteries).
AM I missing something or does this make sense that 24 volts are coming off (2) 6-volt batteries.
