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What Size of Inverter Do I Need?-How to calculate the power of inverter needed?

A power inverter is a device that converts DC power to AC power, often running AC appliances in emergencies or power outages. When choosing an inverter, how to grasp the power of the inverter, I believe that many people have no idea. However, don’t worry, below we will use a simple calculation method to introduce the relevant knowledge of choosing inverters.
Since DC supply is available from different sources, such as batteries, solar panels, portable generators, etc., we can convert DC power to AC power using an inverter running 120 volts or 230/240 volts (generally 120V/240V in the US, 230V in the UK and EU) appliances. In this case, we have to find the right size inverter and battery based on the required load (wattage).
The rated power of the power inverter is always in VA(volts × amps), and we assume its rated power is in watts according to the rated power of the appliance. Don't worry, the basic math in the example below will distinguish the two ratings of the inverter based on the wattage we need.

How to calculate and choose the right size inverter?

Calculate the correct rating of the inverter for the following appliances.
3 Number of fans :3 x 80W = 240W
4 LED lights :4 x 15W = 60W
1 LCD TV :120 watts
1 laptop :110 watts
1 laser printer := 60W
2 phone chargers :2 25W = 50W
Step 1:
First, calculate the total watts required as follows.
240W + 60W + 120W + 110W + 60W + 50W =650 watts
Step 2:
Ideally, a 650W load point would require a 650W inverter, but this is not possible in real life because there are multiple factors that can affect the overall efficiency of the inverter. Because there is no such 100% efficient inverter, this is due to some of the losses and the power factor. This is what we should know about the VA rating of the inverter.
In general, the efficiency of the inverter is 85%-90%(actually according to the manufacturer's label or user manual). To find the VA(volts x amps) rating of the inverter, we divide the calculated power rating by the inverter efficiency or power factor,following below two basic formulas:
Watt power = volts x amps
Power unit VA = Volts x amps x Power factor (efficiency)
Power in VA = Watts ÷ Power factor (efficiency)
By using the third formula (if applicable), we get the inverter's apparent power as follows
Power in VA = Watts ÷ Power factor (efficiency)
Power unit VA = 650W ÷ 0.85 = 765 watts.
Step 3:
Finally, we add the future extension (safety factor) as 1.25 to the calculated wattage. This way, we can add some additional load to the inverter in the future (if needed). In addition, it protects the inverter from voltage spikes and power surges. To do this, simply multiply the calculated number of watts by 1.25 to calculate the appropriate size of the inverter power rating in watts.
According to the calculation, the 1000 watt inverter can safely and smoothly handle the load of 650 watts.
Considering the cost, this is the most suitable inverter size. If you still have any question, you can contact us through forms, emails and other ways, we will be happy for you at any time!
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