Watts are the unit of measurement for a generator's wattage. Calculate the watts needs of your vehicle and electrical items before comparing those numbers to an emitter watt energy capacity. By increasing the amperage and voltage of each device, you may add the total watts number if you intend to power all of your electrical devices simultaneously. Heating systems and washing dryers operate on 240 volts, but the majority of campervan and electronic devices operates on 120 volts. Inverter converters have a regulated wattage of 0.9-5.5kVA and an actual power of 1-6.3kVA, based on the types and brands. Normal generators may produce a total of 5.2–5.5kVA and a recommended output of 4.5–5kVA.