What are AC and DC off-grid solar systems
As the shift in the Australian solar industry moves from grid connected solar with a bias towards feed-in-tariffs and exporting for profit, we are seeing a measurable growth in consumers now wishing the either go off-grid or at the least, set themselves up with grid-connected hybrid + battery systems.
There is a lot of information online regarding hybrid or off-grid solar systems but the question we get asked time and time again is “what are AC and DC off-grid solar systems and which one is right for me”. We want to take the time to write a resource for our existing and newly acquired customers to help you better understand the differences between the two.
DC current
Direct current (or DC electricity) is what solar panels produce and what the battery systems store. This direct current is not directly compatible with your AC powered electrical circuits in your home or from the electricity grid out on the street. DC is defined as the “unidirectional” flow of current; current only flows in one direction. Voltage and current can vary over time so long as the direction of flow does not change. To simplify things, we will assume that voltage is a constant. What does this mean? It means that we can count on most DC sources to provide a constant voltage over time. In reality, a battery will slowly lose its charge, meaning that the voltage will drop as the battery is used. For most illustrative purposes, we can assume that the voltage is constant.
When we apply DC electricity to a DC-coupled solar system, we are referring to the fact that right up until we need to power your home circuits and appliances, we are keeping the solar system in DC. Traditional grid connect solar systems produce DC power out of the solar panels, which are then passed through the AC inverter and regulated for use in your home. A DC-coupled system. DC storage is connected to the output of the solar PV panels and stores DC power directly from the panels.
AC current
An AC-coupled storage system uses a traditional AC inverter (like what you see on nearly every solar installation in Australia), which turns the power into a AC source straight from the panels. It’s AC inverter is connected in between the panels. Depending on the specifics of the system, they can store energy from solar generation as well as the grid or shore power (generator connection).
Want to know more? Read more of our solar blogs to get informed
