Additional Components in a Small Wind System

Depending on your application, you will need additional equipment and materials to provide electricity at the required voltage and current. The following ‘balance-of-system’ (BOS) components are often sold separately (or available as a larger package) and are usually required to complete a small wind energy system:

• Batteries – Used to store the generated electricity if the turbine is not connected to the electrical grid.  The best batteries for a renewable energy system are deep discharge batteries that can be safely discharged a significant amount (50-80% of the battery storage) daily and charged back up the next day.  Properly-sized batteries for your system tend to last 3 to 5 years.
• Inverter – Required if the turbine outputs DC power and you wish to use AC on site or connect the turbine to the electrical grid.  Light duty inverters (100–1,000 W) are typically 12 V DC and suitable for lights and small appliances such as televisions, radios and small hand tools. Heavy duty inverters (400–10,000 W) can be 12, 24 or 48 V DC, and can be used to run just about anything found in a home or small business.  Inverters consume approximately 10% of the generated electricity (treated as a ‘loss’) when converting from DC to AC.  The quality of the output AC electricity is also important.  High quality AC is considered “true sine wave” or “modified sine wave” and is sufficient to safely power sensitive electronic equipment such as computers.
• Rectifier –The opposite of an inverter, this device converts AC power to DC and is used when the AC power from an AC-generating turbine is needed for DC appliances or battery charging.
• Battery Charger – If the generator does not have a battery charging output, a special battery charger is required. Some inverters can act as battery chargers.
• Alternative source(s) of electricity – Required if you do not have the turbine connected to the electrical grid and you need to supplement the wind generated electricity with electricity from a fossil fuel generator or photovoltaic panels (PV).
• Disconnect switches, circuit breakers, fuses and other protective equipment (as recommended by the manufacturer and required by the electrical code) are important for the safe operation of the system. They electrically isolate the wind turbine from the batteries and the batteries from the inverter and load. 
• Monitoring System – Standard monitoring equipment usually includes a voltmeter for measuring battery voltage and depth of discharge, and an ammeter to monitor energy production or use. More sophisticated monitoring equipment includes alarms for system problems such as low or high voltage conditions.

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