RV FEATURE
However you travel , it ’ s important to understand your van ’ s 12V system in order to avoid flat batteries and the associated angry kids ( or spouse ), and fridge full of warm beer .
The problem starts with our technology-centric lifestyle and dependence on modern conveniences . Television , lighting , DVD players , mobile phones , tablets , modems , heaters … they all use power and a surprisingly large amount of it .
FIRST PRINCIPALS
Think about your 12V system like an irrigation system for your garden . Your batteries are like water tanks , with your solar panels working like your roof and gutters to collect rain water and pipe it into the tanks .
Your electrical appliances are like sprinklers . The bigger the sprinkler , the more water it takes from the tank . Small sprinklers use a small amount of water but a lot of small sprinklers running at the same time can use as much water , if not more , than a single large sprinkler .
It is the same with the 12V appliances in your RV . Some , like LED lights , use small amounts of power . Some , like water pumps and stereo systems , use a lot of power . Run a few lights and a TV for a few hours a day and they will use a surprisingly large amount of your battery ’ s reserves .
A typical power system in a modern caravan .
SO HOW DO WE MEASURE THIS ?
Think back to the irrigation system . The water tank ’ s capacity is measured in litres . Let ’ s say it holds 100L . If we water our garden from a single sprinkler , with a flow rate of 1L per hour , our water tank will be empty after 100 hours of watering the garden .
In much the same way , the flow of electricity through the wires of our electrical circuits , called the current , is measured in amps . A battery ’ s capacity is measured in amp hours . If we have a single LED light that draws 1A , it will consume one amp every hour ( referred to as 1Ah per hour ). Left to shine continuously , that light will run the battery completely flat in 100 hours .
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