How does an inverter work?
The voltage of a leisure battery found in a campervan electrical system is typically 12V, and it produces a direct current (DC). Mains electricity found in a house is typically 230V in most European countries (120V in the US) and produces an alternating current (AC). An inverter works by converting the power in your leisure batteries from DC to AC. You will need to use a 12V inverter to use any products that require an AC current (typically those which have a 3 pin plug attached to them).
Pure sine wave vs modified sine wave inverters
There are two main types of inverter available: pure sine wave and quasi (modified) sine wave. The quasi sine wave inverters create an approximation of the AC waveform found in household wall sockets, whereas a pure sine wave inverter exactly reproduces the AC waveform. Quasi sine wave inverters are able to run basic electrical items such as kettles, hairdryers, laptops and blenders, but they’ll struggle to run certain appliances such as sensitive electrical devices. All Victron inverters are pure sine wave inverters.
Inverter/chargers (the Victron MultiPlus)
If you plan on using shore hook up to power your campervan and charge your leisure batteries, you should consider using an inverter/charger. The Victron MultiPlus is an inverter and a battery charger in one. It features a ‘smart’ high-speed AC transfer switch which automatically switches your system from using shore power to your batteries when you’re not connected to a hook up.
This means that whenever you’re plugged into a mains hook up, your batteries will charge and your system will use shore power for any 230V appliances. As soon as you are no longer plugged in, your system will switch to using power from your leisure batteries via your inverter.
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What size inverter do I need?
Campervan inverters need to be sized correctly according to the total wattage of any appliances you will use. Victron inverters have two numbers. One refers to the voltage of the inverter (so in the case of a 12V inverter this will be 12). The second number refers to the maximum operating wattage of the inverter. To calculate the size of inverter you need for your campervan, you should add together the wattage of each appliance you plan on using with your inverter at any one time. We’d also recommend adding at least a 50% factor of safety to future proof your system. Inverters are rated to a maximum wattage, so it’s important that you don’t exceed this or you could damage your inverter.
Inverter size calculator
Our inverter size calculator adds together the wattage of all of the products you might use at one time, and applies a 50% margin of safety to recommend the correct inverter size for your campervan.
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Need help with the rest of your electrical system?
If you’re looking for an overview of campervan electrical systems, have a read of our campervan electrical system guidebook page. Alternatively, if you need to size the rest of your electrical system, try out one of our other calculators.