RV FEATURE
ADD IT UP
If you added up the amount of current draw of all your 12V appliances over 24 hours , the final figure might look scary . Fortunately , we don ’ t run our appliances continuously .
If you have a compressor or 12V fridge , it is necessary to have it switched on all the time and most compressor fridges are rated at around 6A . Fortunately , the compressor doesn ’ t run all the time , even though it is switched on .
The compressor turns on and off to maintain an average temperature controlled by a thermostat . So while the compressor draws 6A , it may only actually operate for 30 minutes during each hour . This is called a duty cycle and most compressor fridges will be rated in the average amp hours they can be expected to operate in average conditions .
Don ’ t be fooled into thinking this is a constant that can be relied upon . In hot weather , the fridge will have to work harder to keep the same internal temperature , so the actual duty cycle may increase to higher levels than specified . Further , as a fridge gets older , the compressor components wear out , meaning it has to work harder to maintain the set temperature , increasing the duty cycle and power consumption .
This inverter shows how many amps it ' s drawing while powering 240V appliances .
Does the inside of your van look like this ?
It all starts with good quality batteries .
WHAT ABOUT INVERTERS ?
Not every device runs off 12V . Mobile phone and laptop chargers , microwaves , coffee machines , food processors , CPAP machines and so on , usually run from 240V mains power .
Many owners fit an inverter to their RV , which effectively turns 12V into 240V , but doing so takes a lot of 12V current . A device that is rated at 300W at 240 volts running from an inverter will end up drawing 30A from a 12V battery .
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