Appliances in a home operate on AC current. Solar and other renewable sources generate DC current. An inverter is required to convert DC current from the renewable source to usable AC current for appliance and other home powering needs. But where does the “charger” part come in? In an off grid application, batteries are used to store energy for later consumption when the sun is not out, or the wind is not blowing. Because there is variability in the renewable source, a generator is often incorporated into the system to charge batteries when needed. Because the output of most generators is AC, a charger is needed to convert AC to DC for the purpose of charging the batteries. Essentially, an off-grid inverter/charger will convert power from DC to AC for consumption and AC to DC for charging.

It might seem redundant to have an inverter/charger and a charge controller, but each serves its own purpose in an off-grid system. The charger in an inverter/charger is an AC charger for an AC source such as a generator. A charge controller allows power from a DC source like a solar array to charge the batteries. OutBack’s family of FLEXmax charge controllers have become the industry standard for efficiency and reliability in off grid and grid hybrid applictions.

A truly off grid solar system must incorporate batteries to achieve true energy independence. Batteries function as the “bank” where excess renewable is deposited and then later withdrawn when needed. Required battery capacity, measured in kWh (kilowatt-hours), depends on the size of the loads that will be powered, meaning that there is no “one size fits all” answer. Other battery considerations include battery chemistry, battery size, storage and recyclability of battery materials. OutBack offers a full line of EnergyCell renewable energy batteries and storage racks to meet virtually any energy storage scenario from simple battery back-up to high capacity and high cycle nanocarbon technology batteries for partial state of charge applications.