If there is one constant trend about Indian summers then it is the increasing heat and longer power cuts year after year. 10 years back having an inverter at home was considered a luxury, but now any house that is being built is already wired for an inverter. There are several good brands such as APC, Microtek, Luminous, Sukam in the market. You would not go wrong with either of these brands, but the first question that comes to mind is what configuration should one go for. This article is for general consumers to help them quickly choose the right configuration of inverter rather than present a technical paper.

There are two parts to choosing the right "configuration" of an inverter -

1. What is the capacity of the Inverter

2. What is the battery back up

Choosing the capacity of the inverter is a bit like choosing how big a car you want. You would go for a bigger car or an SUV if your family is bigger and vice versa. Similarly you choose a bigger inverter if you have a big house (essentially more number of tubes and fans). Additionally, choosing the battery back up is similar to the size of the fuel tank - if you are frequently going on long trips in the car, then you want a bigger tank in the car.

Then there are a whole bunch of other things that are important (but relatively less important) to know. For example: Tubular Batteries vs. Flat Batteries, Half Load vs. Full Load, Sine wave vs. Square wave and the list goes on.

What capacity of Inverter should I go for

How big a car do I need? How big a washing machine do I need? Simply put, this is dependant on the what "load" you will put in the machine. For an inverter, this is simply the total load requirement of all the appliances that you will be using with the inverter (Note: This is the maximum number of appliances that you will be using simultaneously with the inverter). Here is a simple list that gives the load requirements (loads are mentioned in VA instead of watts as inverters are marked in VA as well!) of most commonly used appliances.

Tubelight - 90 VA

Fan - 100 VA

Television - 140 VA

Laptop - 140 VA

CFL - 35 VA

Normal bulbs - 85 VA

Set top box - 70 VA

DVD Player - 70 VA

So, if you think you will be using 2 Tubes, 2 Fans, 1 TV, 1 Laptop and 1 Set top box during a typical power cut. Your capacity requirement will look like this:

Tubelight - 90 VA x 2 = 180 VA

Fan - 100 VA x 2 = 200 VA

Television - 140 VA x 1 = 140 VA

Laptop - 140 VA x 1 = 140 VA

CFL - 35 VA x 0 = 0 VA

Normal bulbs - 85 VA x 0 = 0 VA

Set top box - 70 VA x 1 = 70 VA

DVD Player - 70 VA x 0 = 0 VA

So, the total load is 730 VA. In this case, choosing a common configuration of 800 VA is good enough.

Tip 1: 1 KVA refers to 1000 VA and 2 KVA refers 2000 VA etc.,

Tip 2 : In the context of a home inverter, anything that has moving parts should not be connected to an inverter. Examples: Printer, Microwave, Mixer, Blender, Washing machine. In addition, some power guzzlers which do not have any moving parts also cannot be connected to the inverter either. Example include Iron, Induction cooker, Geyser, Immersion rod.

What battery backup is good enough

Once you know what capacity of inverter you should go for, then the other question is for what duration do you need back up power. During summer, do you have power cuts occasionally, or do you live in an area or a state that has long power cuts? In India, 3 hour back up is most common and 4 hour back up will take care of even the longest power cuts.

Battery capacity = (Inverter Capacity x Required hours of backup)/10

So, if your inverter capacity is 800 VA and you want a 3 hour backup, then your battery capacity should be:

= (800x3)/10 or 240 AH.

Batteries are generally available in 110 AH. So two of these battery are good enough.

Still confused?

This article is aimed at simplifying the purchase decision of an inverter in a quick and dirty manner. We tried our best to keep this article simple and easy to understand. However, if you are still confused or have specific question, please do not hesitate to call our product specialist on +91 88614 33501 (9 AM to 10 PM on all days including Sundays and Holidays).

Choosing the right Inverter configuration