The inverter is a basic component on most systems which converts low voltage DC power from the batteries into high voltage (120 or 240) AC power as needed.

Most inverters we sell produce only 120 VAC as once the major electric appliances are replaced with gas appliances (range, oven, water heater, heating and air conditioning),there is little need for 240 VAC power. Exceptions include larger submersible pumps and shop tools which can be powered either by the generator or a step-up transformer (or by a larger or second inverter).

Two types of inverters are modified sine and sinewave. Least expensive are modified sinewave units which will operate all but the most sophisticated electronic devices. Sinewave inverters produce power nearly identical to the utility grid, will operate those delicate laser printers, etc. but cost m ore per watt of output.

Inverter Components
While an inverter is a substantial portion of the cost of a system, it is really a subsystem that includes a number of additional components. To make a safe, reliable installation one should provide the following

• Inverter to battery cabling
  Because of the high current required on low voltage circuits, this cable is large, commonly #2/0 to #4/0 in size. Smaller conductors than required are unsafe and will not allow the inverter to perform to its full rating.
• DC input disconnect and overcurrent protection
  It is important to have a safe installation with a properly sized DC rated, UL listed disconnect. Typically the disconnect works in conjunction with an overcurrent protection device such as a fuse or breaker. These components are installed in an electrical enclosure which can also house shunts.
  
• Shunts
  Are used to read the amperage flowing between the battery and inverter. This device is installed in the negative conductor. It can easily be housed in the disconnect or its own enclosure.
• AC output disconnect and overcurrent protection
  I If the breaker panel which is fed from the inverter is adjacent to the inverter, then the main breaker will serve as the inverter output disconnect and overcurrent protection. If, however, this panel is not grouped with the inverter, then a separate unit should be installed. This also holds true with AC circuits coming to the inverter from a generator or utility source. A second breaker may be needed if these breakers are not grouped.

Inverters with built-in battery chargers
Many of today's inverters incorporate battery charging circuitry. This is easily and economically accomplished because of the design of most inverters. Inverters step up low voltage and change DC power to AC power. Battery chargers do the reverse of this. Additional circuitry is all that is required to add a second function and economically create an Inverter/Charger.

Transfer switches are also incorporated into these Inverter/Chargers so that the AC loads can be powered directly from the generator when the battery charger is operating.

Comparing Inverters

• Continuous wattage rating
  Hour after hour, what amount of power in watts can the inverter deliver.
• Surge Power
  How much power and for how long can an inverter deliver the power needed to start motors and other loads.
• Efficiency
  How efficient is the inverter at low, medium and high power draws. How much power is used at idle.