How to Calculate Power Ratings and Capacity of an Inverter

In this chapter you would find out how to calculate power ratings and capacity of an inverter. Knowing the power ratings and capacity of an inverter will help you decide the type of inverter you need for your home or office. Inverters have become very vital in our everyday life as constant power cannot be guaranteed.

There are some information you need to have before deciding to buy an inverter. The capacity of the inverter you need can be determined by the usage. For example if you need the inverter for your home, the load in your house will determine the capacity of inverter to get.

If the inverter is needed as a backup for your office you should first look at the things you want to backup, their capacity. That would determine the size of inverter you will be going for. There are ways to calculate and known the capacity of inverters you need without having to depend on the seller for the information.

This can be achieved by simply adding the total power of the load which you want to run off the inverter. Below is an example of power ratings of different everyday use equipment that would guide you when making your own calculation.

Fan25 – 80 0.1 – 0.4
washing machine800 – 10004 – 4.5
energy bulb200.01
Music system20 – 400.09 – 0.17
1HP AC1000 – 15004.3 – 6.5

When you have taken down every detail like the table above, you then sum them up. To find your inverter capacity, you would need to divide the total power rating by the power factor. What you get should be the range of your inverter capacity.

The next line of action would be to calculate the capacity of your battery. You can achieve that by applying the following formular:

If you know the watts instead of the amps, follow the following procedure:

Convert watts to amps. Actually, watt is the fundamental unit of power and watt-hour is the energy stored. The key is to use the watts you know to calculate the battery voltage.

For example, say you want to run 250watt 110VAC television from an inverter for 5 hours.

watt-hours = watts x hours = 250w x 5hours = 1250watts-hours

where efficiency of the inverter is 85%

Therefore, watts-hours = watts x hours / efficiency = 1250 / 0.85 = 1470 watt-hours.

Since watt = amps x volts, divide the watt hour by the voltage of the battery to get the battery to get amp-hours of the battery storage.

So amp-hours (at 12volts) = watt-hours / 12volts = 1470 / 12 = 122.5AH

Since you have learnt how to calculate power ratings and capacity of an Inverter. You are free to go and choose the inverter, whose values and ratings are the nearest to your required values.

I hope this little tutorial has shown you how to how to calculate the power ratings and capacity of an inverter. keep visiting us for some more information and guidance

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