RV FEATURE long periods . When sizing an inverter , always look at the nominal or continuous power output .
The other consideration : you may want to power more than one device from your inverter at the same time . For example , you may want to run a 700W microwave and a 1000W electric kettle at the same time . To do that you will need an inverter with a nominal output of at least 1700W .
The table on page 16 shows the typical power ratings for some common electronic devices .
Top tip : If you add up the power requirements of all the devices you think you will need to run at the same time , you may come up with a very high figure . The cost of that size inverter will be huge . You need to be sensible about what devices you run at the same time . Do you really need to run the toaster and the microwave together ? By managing your power requirements , you can get by with a smaller inverter .
This cTek 15-amp battery charger will consume around 638-watts
HOW MUCH BATTERY CAPACITY DO I NEED ?
Determining how much battery capacity you will need to power your inverter is where things get a bit tricky . As you know , 240V appliances are generally rated in watts , whereas 12V appliances are rated in amps and batteries are rated in amp-hours . Using Watt ’ s law , we know that a 1000W 240V kettle draws 4.2A , but that is at 240-volts . Remember : to get 240V from a 12V source , we need to pump in more amps . As it turns out , it is quite a bit more .
To calculate the amps draw at the battery , we use the same formula , but at 12V instead of 240V . So our equation becomes 1000 ÷ 12 = 83.3 . Yes , that ’ s correct : 83.3A . And wait , there ’ s more .
This Ryobi battery charger is clearly marked as 55-watt input on the serial number lable
A slightly different Ryobi battery charger . This one required 60-watts input
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