How to Convert a John Deere 4020 From Two Batteries to One

The John Deere 4020 is a classic, but it can benefit from a 12-volt conversion.
••• Thinkstock Images/Comstock/Getty Images

Things You'll Need

  • Socket and wrench set
  • 12-volt alternator
  • 4 threaded rods and nuts, 3/8 inch
  • Alternator tensioning bracket
  • #10 wire
  • #16 wire
  • 12-volt starter
  • 2 tension bands, 1 inch
  • 4 bolts and nuts, 3/4 inch

The John Deere 4020 tractor was manufactured with a pair of 12-volt batteries wired in series. Both batteries are wired to the 24-volt starter, with all other electrical systems being divided down the middle. One battery runs all the electrical systems on the left side of the tractor, while the other battery runs all the systems on the right. However, it can be difficult to keep both batteries evenly charged. Therefore, it may be preferable to convert the tractor to run from a single 12-volt battery using a modern 12-volt starter.

    Disconnect and remove the batteries. Remove the generator by disconnecting the generator belt from the fan and unbolting the generator from its mount. Remove the fan along with its mount and the voltage regulator.

    Install a 12-volt alternator on the generator mount. Use an alternator tensioning bracket to hold the alternator in place and secure it using four three-eighths threaded rods. Connect the alternator to the water pump using the generator belt.

    Run a length of No. 10 wire from the battery terminal on the alternator to the ammeter. Connect the battery terminal to the "2" terminal on the alternator using a short length of No. 16 wire.

    Remove the 24-volt starter. Place the 12-volt starter on its bracket and secure it using a pair of 1-inch tension bands with three-quarter-inch bolts. Connect the positive and negative leads from the starter to the corresponding terminals on the alternator.

    Connect the ground lead to the negative terminal of one of the 12-volt batteries. Connect the starter cable to the positive terminal of the battery.

    Tips

    • If your tractor was outfitted with 6-volt bulbs, replace them with 12-volt bulbs before connecting the battery. The alternator will provide a full 12 volts to the sockets, and will burn out 6-volt bulbs in short order.

Related Articles

How to Build a Battery Isolator
How to Charge a 12V Battery With a DC Motor
How to Make an Electric Motor Using a 9V Battery
How to Test Lithium Ion Batteries
How to Convert a Generator to a Alternator
How to Build a Space Station Science Project
How to Build a Model Electricity Generator
What Is the Difference Between a Windmill & a Wind...
How to Build DC to AC Power Inverters
How to Rewire an Electrical Motor to Generate AC Current
How to Make an Electrical 'Jacob's Ladder'
How to Convert Horsepower to Foot Pounds
How to Build a 120V AC to 12V DC Power Converter
How to Wire a Battery in Series
How to Convert Tenths to Hundredths
How to Convert HP to BTU/hr
How to Use a Voltmeter on a 12 Volt
How to Make Your Own Cooler as a Science Project
DC Generator Vs. Alternator
How to Make a 12 Volt Heater