The task of air conditioner in the car or caravan isn’t only to lower the temperature, but also to reduce humidity, which provides bigger comfort on hot, damp days. But what is the most important when we intend to mount air conditioning?
In the previous article we’ve mentioned that it's best to consider compressor air conditioners, and such can be found in the offer of one of the most popular manufacturers of camping accessories - Dometic.
What 'air con' should we choose?
Among the devices that provide thermal comfort, we can distinguish rooftop air conditioning units (with or without window) and false floor air cons (placed in compartments at the bottom of the caravan). Particular models may differ from each other, mainly with performance and power consumption. Unfortunately, the more efficient air conditioning the more power will be needed in comparison with those of weaker performance.
When choosing air con version appropriate for our vehicle, we should take into account its length (the more surface area for cooling, the higher should be its capacity), the number and size of windows (vehicles with smaller amount of windows are easier to cool) and even an alcove over the driver's cab (if it covers the windshield it acts as a shading).
Very important is also the fact what destinations we choose the most often. If a motorhome or caravan will be used mostly during hot days, and we mainly go down to the south of Europe, we will need more efficient air conditioning than in a situation where we choose much cooler parts of the world, or if we travel outside the summer season.
We can also use the recommendations of manufacturers. Eg. Dometic recommends that the basic model of roof air-conditioning - FreshJet 1100 should be installed in the vehicles with the length of up to 5 meters. The most powerful model - FreshJet 3200 is recommended for the longest motorhomes and caravans (over 8 meters).
Air conditioning vs. electricity
However, customers may have doubts whether the purchased device doesn’t consume too much power. Of course manufacturers are trying to reduce the energy consumption. In practice - in case of Dometic products - depending on the model, we can expect that the consumption (in cooling mode) will oscillate around 430 W and 1300 W.
Regardless of what parameters the device will have, the air conditioner requires a lot of power during the start-up phase. This may be particularly problematic if on the campsite we would like to connect the air conditioner to an external power source. Therefore, Dometic in FreshJet 2200 model (and in higher ones) has applied the SoftStart function. It allows you to run the air conditioning without problems also on campsites with limited current access. As provided by the manufacturer, the start-up phase in these devices significantly reduces the power consumption during this phase, distributing it proportionally in time. Air conditioners are also resistant to voltage fluctuations.
In the case of poorly secured campsites it can happen that the air conditioner will not start. To prevent this situation, you can use a device called Waeco CombiPower. It’s a combination of a sinusoidal wave inverter and an automatic charger. When using external energy sources, the device detects a limited power capacity and will power it with a battery. If an external source is cut off, it automatically turns on the inverter with UPS function, which will power the connected receivers with sinusoidal voltage.
So the air conditioning could also work while driving and at a standstill without access to the 230V power supply we must install a special DC set that will collect current from a 12-volt additional battery. This device is equipped with charging current distributor, which automatically turns off the air conditioner when the risk of discharging battery appears. An additional advantage of this system is the possibility to control the charging process of the main and additional battery while driving.
Quite an expensive though really nice addition related to the air conditioner would be a power generator run by petrol, diesel or LPG. Thanks to it, the power supply of onboard devices can take place even when we don’t have an access to the external power source.