PLEASE USE THIS VIDEO FOR INFORMATION PURPOSES AND TAKE ALL PRECAUTIONS WORKING ON POWER EQUIPMENT, FAILURE TO DO SO COULD KILL OR SERIOUSLY INJURE YOU. The battery on my lawn tractor started going dead and I’d notice the needle was staying on the negative charge side of the amp meter so I dug into the charging system and here is what I found. The charging system is pretty simple, the engine has an alternator under the flywheel that puts AC volts into the Voltage Regulator, the regulator changes it to DC volts and regulates the output, the output goes to the battery via a wire that may go through a relay and fuse. If you have plenty of AC volts coming out of the alternator and battery volts (less than 12.5 volts) on the wire going to the battery (at the connection to the regulator), the voltage regulator is the only thing left and is probably bad. What you see in this video should apply to any engine with a 3 wire voltage regulator. Unfortunately the regulator itself can’t be checked with a normal volt/ohm meter so this diagnosis is through process of elimination.