Difference between watts, VA and Ah
Understand the three ratings used when planning appliance load, inverter capacity and battery energy.
Watts describe the appliance load
Add the running watts of the appliances that must operate together. Starting motors or compressors may need a separate peak allowance.
VA describes inverter capacity
Inverter capacity is often rated in VA. Power factor and a visible planning margin connect the real-watt load to the VA requirement.
Ah needs a voltage and runtime
Battery Ah is not energy by itself. Combine it with bank voltage, usable depth of discharge, inverter efficiency and load to estimate runtime.