Induction cooktops were unheard of not long ago . Now , they are standard equipment for many caravanners .
USING POWER OVER TIME
Any device ’ s watt rating is essentially how much power it will use at any one moment in time . However , we need to look at power consumption over time to know , for example , how long our batteries will last using a certain load .
To do that , we refer to a watt as a watt-hour ( Wh ). So a 10W LED light will consume 10Wh per hour . Going the other way , we know a 25A battery charger will output 300W . Expressed over time , that ’ s 300Wh per hour going back into our battery .
BUT BATTERIES ARE RATED IN AMP HOURS
To account for the fact batteries are rated in amp hours , we use Watt ’ s Law again . To calculate the watt-hour capacity of a 100Ah , 12V battery , we apply our formula : 100Ah x 12V = 1200Wh of battery capacity . Everything is rated in watts .
Hopefully , now you can see where this is all leading . Except for your batteries and battery chargers , every other appliance in your RV will likely be rated in watts . Solar panels , microwaves , generators and inverters . The one thing that changes is the voltage .
Solar panel voltages will vary depending on the type but most used in RV applications will range between 17 and 25V . Householdstyle appliances , such as microwaves , air-conditioners and induction cooktops use 240V . General fittings , such as LED lights , the water pump and perhaps your TV will use 12V . If you had to use amp hours as the basis for understanding your RV ’ s electrical system , you ’ d have to convert all these individual values . The beauty of using watts is that it remains constant across all voltages .
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