Selecting the right inverter for your home has become a tough task these days. There are so many terms we need to understand – 800VA/ 1000VA, Tubular Batteries/ Flat Batteries, Half Load/ Full Load and the list goes on. And on top of all these, availability of multiple power back up solutions and misleading information provided by sellers have further added to buyers woes. So I did some research and study before buying an inverter for my home and I’m sharing the details of same so that you don’t have to go through the same problems while buying an inverter.
So What do You Need – UPS or Inverter?
This is one of the basic confusion people face, so let me start with answering this first. UPS and Inverter are words used interchangeably though there are not exactly same. UPS (Uninterrupted Power Supply) is just a system which allows INSTANT switchover to the power back-up source in case of a power failure. The power back-up source can be a battery or something else. Whereas an Inverter is a system which converts direct current to alternate current hence enables using a battery for backing up equipments running on AC power supply. Inverter uses a battery to provide power back-up. Computer UPS comes with in-built battery which works as back-up power source and can provide back-up for 15min. to 30 min. So if that much of back-up is sufficient for you, you should be fine with buying just a UPS for your need. But Inverter comes with more powerful battery and can provide support for electrical equipments, computers, home appliances etc. and also gives more hours of back-up. Most of the inverters come with in-built UPS which ensures that power failure doesn’t cause fluctuation and your system switches instantly to Inverter’s Power Back up battery.
What Capacity of Inverter is Good for Your Home?
Once you are sure that you are looking for an Inverter, it’s important to calculate the capacity of Inverter that will suit your requirement. Following table will give you brief idea about the power consumed by various equipments.
Tubelight – 60W
Fan – 70W
Television – 120W
Laptop – 100W
CFL – 25W
Modem – 50W
Now you are in a position to understand as what capacity inverter do you need and I’ll let you do that in 3 simple steps –
1. CALCULATING YOUR POWER NEED
Now I’ll explain you how to use above table to calculate the right capacity Inverter for your need. Let’s say you need Inverter to run 2 Tube lights, 3 Fans, 1TV and 1 Laptop. As per the table above, you’ll need a total power of 550W(=2X60 + 3X70 + 1X120 + 1X100) to support all of your equipments at the same time.
♣ Your Total Power Need = 550W
2. CALCULATING REQUIRED INVERTER’S CAPACITY
Now that you know how much power is required, it’s easy to get the VA rating of inverter. In ideal condition, the VA rating would have been same as the power need i.e. 550VA. But in practical conditions, the power factor of Inverter is less than 1 hence power supplied by 550VA Inverter won’t be 550W but lesser than that. Assuming power factor of Inverter to be 0.7, following are the details of calculation –
Required VA of Inverter X 0.7 = 550W
♣ Required VA of Inverter = 550/0.7 = 786 VA
Now luckily we have inverters available in the market with 800VA capacity, so such inverters will fit into my requirement.
3. CALCULATING BATTERY CAPACITY
Till now, you will have clear understanding of the Inverter capacity required for your need. But the next question is that how much back up will the inverter provide and for how many hours you can run all of your equipments. And that’s where battery capacity comes into picture. It’s the battery which determines the back-up hours. The higher capacity battery you have, the more back-up hours you’ll get. So lets get into the calculation fast.
Required power(in Wattage) X Required back-up hours(in Hours) = Inverter Voltage(in Voltage) X Battery Capacity (in Ampere Hours)
Let’s look for an Inverter which can give back-up of up to 3 hours, so for our case –
550W X 3Hours = 12V X Battery Capacity
♣ Battery Capacity = (550 X 3)/12 = 137 Ampere Hours
So we need a battery of 137AH capacity but if you check the market you’ll find batteries of 130AH capacity. So that should be more or less sufficient for your need.
Finally, we have come to the conclusion that if we go for 800VA Inverter with 130AH battery, I can run 2 Tube lights, 3 Fans, 1 TV and 1 Laptop for up to 3 hours. And by the end of this article you don’t need to rely on sellers for understanding your need as you can do the calculations yourself in just 3 simple steps. Hope this article helps you in some way in making the right decisions. Let me know if you need any other inputs.