Alternators are responsible for turning mechanical motion into electrical energy, which is typically directed and stored in a battery. You may find yourself in a situation where the high voltage output of an alternator overcharges a deep-cycle battery, which could lead to expensive replacement batteries. On the other hand, your alternator may not produce enough voltage, which could mean your battery is not being charged properly, if at all.
Open the alternator housing by using a socket wrench. Remove the wired coils and unwind the wires from the inside parts of the alternator. Rewind the coils with thicker wire, which will produce greater voltage as the alternator turns.
Wire a DC to DC converter to the output terminals of the alternator if you do not want to open up the alternator and rewind the coils. A DC to DC converter will increase the voltage output from your alternator system. There are different types of DC to DC converters, depending on how much voltage is entering the system as well as the voltage output of the converter. Along with the various types of converters, each may have a different way of attaching wires. Some may require soldering while others have screw-in input ports.
Install a 10-amp diode to the output wires from the alternator's stator, which will result in a 0.6-volt gain in net voltage for the system. According to SmartGauge Electronics, soldering the diode into the wiring of the alternator's output tricks the regulator into thinking the alternator is not producing as much voltage. The diode also must be equipped with electrical isolation and a metal heat sink. It also is important that the diode is able to accommodate the full rotor field current from the alternator.
Replace the alternator regulator, which serves as a computer for how much voltage the alternator produces and sends to the battery. The regulator is replaced by using a socket wrench to remove the regulator from the alternator assembly. In most cases, the regulator is placed directly adjacent to the alternator and is wired to the alternator's input ports.
Open the alternator, as in the previous section, and change the wired coils. Unwind the coils and rewind them using a lighter gauge wire, which will result in less voltage. Many wind turbine systems that use vehicle alternators require this modification due to the typical alternator setup that requires high revolutions per minute. Renewable energy systems that use car alternators have a lower rpm range, in most cases.
Install a resistor or a diode to the alternator's output wiring. Use a wire stripper to cut the cable leading to the battery from the alternator. Strip 4 inches from the exposed wiring and solder the wires to the resistor or diode. A resistor with a 0.1 Ohm rating will drop the voltage by one volt, according to Excel Auto. Wrap the solder with heat shrink wrap and seal the wrap with a lighter.
