Motorhome Mains Power

Remote 240 volt power sources

There are 3 ways you can get 240 volt mains power into your motorhome. Electric Generators, RV Power Inverters, and Mains Power cord.

1 - Voltage Inverters

A voltage inverter converts a low DC voltage battery supply to a mains voltage AC line supply. Inverters either produce an AC voltage waveform as a square-wave or preferably as a sine-wave.

These are the 2 types of voltage inverter that we shall be concerned with here. A square wave or what is now more commonly called a "modified sine-wave" or "quasi" is the cheaper of the 2, and is best suited to appliances without electronic controls or induction motors.

The pure sine-wave inverter produces a waveform the same as your home mains supply and will run all electronic appliances without adverse effects. A pure sinewave inverter is a lot more expensive and often costs several times more than a comparable square-wave inverter.

Square-wave Inverters

These are best suited to resistive loads such as hotplates, heaters, drills, grinders, mixers, blow dryers etc. Even basic microwave ovens will groan and be extremely noisy when trying to run from a square-wave inverter! Large square-wave inverters can be purchased for around $100 on eBay.

Pure Sine-wave Inverters

These are the best and will run a microwave, stereo, television, gaming console, or computer the same as at home. Decent sized sine wave inverters vary in cost from $700 to several thousand dollars depending on the wattage of the unit.

Inverter power ratings

Be warned - an inverter advertised as "1200 watts" may really only be capable of producing 500 watts constantly. Inverters have 2 power ratings. The first is the constant power the inverter is capable of producing all day, this is the real power output of the inverter. Inverters are also capable of producing a much higher "Peak" wattage for a short period of time. ie: 1200 watts for 5 seconds. This is the peak or startup wattage often drawn by motors etc when they first start. Your inverter cannot power an appliance that has a greater wattage than the constant or continuous rating of the inverter.

2 - Generating Sets

Generating Electricity

A generator is an engine driven means of producing mains voltage AC power. Fuelled by petrol, diesel, or LPG generators are noisy, fuel guzzling, and inefficient. However, a generator is a good backup for remote area power systems.

Portable generators, like inverters, vary in power capacity, and are available with wattages ranging from 500 watts to over 20,000 watts for motorhome applications.

An 800 watt generator will not produce enough power to run a 1200 watt hotplate or a welder, so it is important to purchase a generator that is larger than your expected maximum power consumption.

3 - Mains Power

Plugging in at van parks

Well this is the most reliable form of electric supply. An extension cord from your motorhomes power box to the power supply outlet in the caravan park that you are staying at.

One important factor to remember here, is that caravan parks charge for power at the industrial rate tariff, which is a lot dearer than what we pay for electricity at home.

Again, it is important to remember that the maximum power that you should be drawing through the cable will be around the 10 to 15 amp mark, depending on the size of the circuit breaker or fuse that the caravan park has in the power box, and the rating of your extension cord.