Determining inverter capacity for off-grid solar systems

Determining inverter capacity for off-grid solar systems is simplified by looking at what utilities have already established for grid-connected homes. Most homes are connected to the grid with a 40A breaker, which equates to around 10kW. In some cases, a 40A breaker can handle up to 60A for short periods, reaching nearly 16kW. However, data from Powercor shows that most houses never exceed a 6kW maximum demand. Therefore, our approach is to always install a minimum of two 6kW inverters in any standard home, which consistently covers the demand without any issues.

Of course, some houses may have higher demand and may require a 3-phase system and higher surge capacity. These requirements can easily be addressed by making some calculations and either using a larger inverter or employing soft-start technology for motors. Nowadays, modern houses are equipped with technologies like soft start or variable speed drives for motors, which greatly reduce the need for high surge capacity. We are living in the 21st century, where such technological advancements are readily available to accommodate various electrical needs.