Understanding Generators for Caravans

Whilst CaravansPlus does not claim to be a one stop generator shop with more generator brands, types and sizes than you can poke a stick at, what we have done is hand select a couple of dependable mid range generators at affordable prices to offer our customers.

We understand it is easy to become overwhelmed with choice, and choosing a generator to suit your requirements can become a daunting task. There is no simple formula. The options we offer include offerings from Briggs and Stratton, along with Aussie Traveller, who are also a well known and established brand within the caravan fraternity spanning multiple decades. Most of our customers would like to have the ability to run their caravan air conditioner as their largest appliance, so we will start there.

Air conditioners sold by CaravansPlus range between 2.4kW to 3.3kW cooling and 1.4kW to 3kW heating capacities. On the other hand generators are generally advertised as watts. A Kilowatt (kW) being 1,000 watts makes for a fairly easy conversion using kW divided by 1000 = watts. As such a generator in the vicinity of 2000W to 4000W may be required depending on the air conditioner you have. In addition, there are a few terms which need to be taken into consideration when selecting a generator.

Rated / Continuous Output

This is the continuous power required by an appliance to run for extended periods.

Maximum Output

Appliances start at a higher wattage than the rated or continuous output. This is the maximum wattage output the generator is able to produce in a short bust. This burst of wattage is required to be available when an appliance starts.

Start Load

A start load is the power an appliance pulls at start up, and depending on the type of appliance this can vary greatly. Essentially if the appliance has a motor, impeller, or shaft driven load it will be higher than an appliance without.

An example would be a fan. The blade is connected to a shaft which is connected to an electric motor. When the fan is switched on, there will be a greater pull of energy to allow the magnets in the electric motor energise, in turn spinning the shaft and then the initial resistance on the fan blades. Once the fan is up to speed, it will only require enough energy to keep the blade spinning, and that energy will be nowhere near as much as it required to get going. On the other hand, a toaster or sandwich press has no moving electric parts, and will operate at a rated or continuous output.

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Inverter vs Non-Inverter Style Caravan Air Conditioner Considerations

Whilst there has been a move towards inverter technology within caravan air conditioners in recent times, there are some older non inverter style units in great numbers out there. It is important to also consider that an older style non-inverter type will have a much larger pull at start up than the newer inverter type, of which will comfortably run on a quality true 2000W generator. If you have an older unit, you will also need to consider 2000W might not be sufficient for your requirements.

2000W, 2500W, or 3500W ... What's in a Name?

Many generators are advertised with a number relating to their wattage and some manufacturers will mislead the buying public in a number of ways. For example a cheap generator which we will call the Phoenix Spark2000 could be assumed as a 2000W continuous or rated output, however this can be far from the true. This could be its maximum output or just a model number, whilst rated output may only really be around 1600W. On the other hand a quality generator from a reputable manufacturer will number their generators with the number corresponding to the rated output. It is a matter of buyer beware.

Temperature Impact & Other Voltage Drop Factors

These factors are not commonly considered by most when purchasing, however they may play a small part when consideration is given to smaller generators, particularly where you plan to run other appliances at the same time, or already running to the edge of your requirements! Temperature. If the ambient temperature is over 25 degrees celsius, then a good rule of thumb is to factor in a 1.5% decrease each 5 degrees thereafter. Whilst this may not seem to be much, this can prove to be a factor especially in hotter weather.

25C	30 C (- 1.5%)	35 C (-3.0%)	40 C (-4.5%)
2000W Generator	1970W	1940W	1880W
3000W Generator	2955W	2910W	2865W

Other factors influencing voltage drop will include the height above sea level at which the generator is used, (may not be a huge issue in most parts of Australia), and the length of your extension lead which should be around 4m - 5m at most in length. Longer will certainly lead to voltage drop. The lead must be of good quality.

Final Thoughts

Always consider other applications for your generator. Will you be wanting to use it on the farm, or as an emergency back up, or how about simply running other appliances when caravan and camping alongside running your air conditioner?
It may pay to slightly over estimate your requirements should any of these considerations be plausible possibilities.