Off grid inverters all have overload capacity. For example, a 3kW off grid inverter can support the start of a 1kW motor, with a maximum instantaneous power of 6kW. Some people believe that the energy of this instantaneous power needs to be provided externally by the inverter, but in fact, millisecond level energy cannot be provided by the photovoltaic or battery, but the inverter can provide it. There are energy storage components inside the inverter - capacitors and inductors, Both can provide instantaneous power. The charging and discharging of batteries all use the same cable, so when designing, it is necessary to calculate the actual charging and discharging current. Choose which one is the largest, such as a 5kW inverter with a 4kW component and a 3kW load. The battery is 48V600AH, and the maximum charging current of the inverter itself is 120A. The maximum charging current of the photovoltaic system is 80A. When the load is maximum, the maximum discharging current of the battery is 65A. If the inverter does not support simultaneous charging of photovoltaic and municipal power, The cable is selected based on 80A, using 16 square meters. If the photovoltaic and mains can be charged simultaneously, the current can reach 120A, and at this time, the cable needs to use 25 square meters.