Key considerations when spec’ing an inverter

Power supply condition continues to be poor in India with power failures ranging from 2 to 4 hours in cities and 8 hours or more in small towns & villages. This makes it difficult to manage daily life & thus switching to power backup solutions has become the need of the hour.

When we think of a power backup solution the first thing that flashes in our mind is the inverter-battery pair, isn’t it? When somebody plans to purchase an inverter, there are some vital points to be taken into consideration. In this blog, we will try to throw light on all the answers that you desire.

First, understand your Power Requirement

Before purchasing the power backup solutions, the most important thing is to understand your requirement. To evaluate the power requirement, it is very important for you to know two things upfront:

  • The total load that you want to run on backup : This is essential to get the right size of the inverter of power backup solution. And from size, we mean the VA value. To get to the VA value, it is very important for you to know the wattage (or watts) of each appliance that you want to run on the backup. More details on this are explained in the section below.
  • The total number of hours for which backup is required : This is essential to size the batteries that you need.

Types of Inverter and How to Choose One

There are two types of inverters available in Market : Pure Sine Wave Inverter and Modified Sine Wave Inverter (or Square Wave Inverter). The choice will depend on the kind of appliances that you have. If you want to run electronic appliances (like TVs, Computers, etc) on inverter, then go for Pure Sinewave Inverter, else you can go for Modified Sine Wave Inverter.

Point to be noted : Modified Sine Wave Inverter can cause slight humming noise when used with induction motors like ceiling fans, etc.

Difference between UPS and Inverter

Although used interchangeably, there is a difference between UPS and Inverter. The basic function and architecture remain the same, but the difference is minor.

The difference between a UPS and Inverter lies in the time in which it can switch to battery power when a power cut happens. A UPS can switch to battery power in 3-5 milliseconds, whereas an inverter does it in 100 milliseconds. The choice between the two will depend on how critical is the switching to backup for the appliances that you want to support. For e.g. a desktop computer would need faster switching as you can lose data if it switches off even for a few milliseconds.

Key considerations when spec’ing an inverter

Even in UPS, there are Online and Offline UPS

Online UPS are those in which the power is drawn from the battery irrespective of the availability of power from mainline. This makes sure that there is no loss of work even for a few milliseconds when there is a power cut.

Offline UPS is one where the power is drawn from battery only when there is a power cut. All other times it is drawn from mains.

Key considerations when spec’ing an inverter
Key considerations when spec’ing an inverter

Types of Batteries and how to choose one

There are 3 types of batteries available in the market: Flat Plate, Tubular and SMF. Without getting too much into details, all we can say is that Tubular Batteries are the best choice for inverters. They may cost slightly more than Flat Plate, but they will last longer. SMF batteries may sound good, but they have lesser life (4-5 years as compared to 7-8 years of a tubular battery). But the most important thing to run batteries for a long time is to make sure that it is topped (filled) with distilled or RO water frequently & the fluid levels are maintained.

What is the “C rating” of batteries?

Although it is irrelevant to think about this while buying batteries, we would like to put limelight on this concept too. If you are not curious, you can choose to ignore this section.

But if you are curious then the C rating (or the coulomb rating) of the battery is the measure of the rate at which a battery is discharged relative to its maximum capacity. A 1C rate means that the discharge current will discharge the entire battery in 1 hour.

A C20 rating battery is considered ideal for the inverters and that is the C rating with which most inverter batteries are available in the market. So if you ask for inverter battery, you will mostly get one with C20 rating.

Other things to consider

Warranties : While purchasing batteries, one must look for maximum warranty. An inverter battery combo of the same brand is useful at times as manufacturers send their engineers for maintenance on a regular basis, which increases the life of the inverter/battery system.

The inverter is a maintenance-free product and shall not require any scheduled maintenance except failure attention. Maintenance is only needed for batteries.

All set to buy a power backup solution? Spot on!

Grab the best Inverters/UPS here,


By Team Indus Powers

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