Are your user planning to buy a new inverter or upgrade your old one? Whatever maybe the reason, it is very important to understand what is the right inverter for user requirement. The power requirement can be differ from other user. So do not just blindly install the same inverter (in terms of power). Before buying an inverter do a little homework and understand the basics.
First understand your Power Requirement
One of the most important factor that you must know before buying an inverter is your “Power requirement”. In simple words- what all electrical appliances (like fan, tube lights, television, CFL etc.) you want to run at the time of power failure. The power requirement is addition of the power consumed by various electrical equipments.
Suppose you want 3 Fans, 3 Tube lights, 1 CFL & 1 television to operate at the time of power failure. Below is the power consumed by these items:
- 1 Fan – 70 Watts
- 1 tube light – 60 watts
- 1 CFL – 25 watts
- 1 Television – 120 watts
Therefore your total power requirement is ( 3*70 +3*60 + 25 + 120) = 535 watts
Find the VA rating of the inverter you need
It stands for the Volt ampere rating. It is the voltage and current supplied by the inverter to the equipments. If an inverter operates with 100% efficiency, then the power requirement of the electrical items and power supplied by inverter is same. But we all know that 100% or ideal conditions don’t exist in real. Most inverters have the efficiency range from 60 % to 80%. This efficiency is also called power factor of an inverter and is simply the ratio of power required by the appliances to power supplied by an inverter. Power factor of most inverters ranges from 0.6 to 0.8.
Hence Power supplied (or VA rating of inverter) = Power requirement ( power consumed by equipments in watts) / Power factor( efficiency).
Here average value of power factor or efficiency is considered i.e. 0.7
Power of inverter (VA) = 535/0.7 = 765 VA
In the market 800 VA inverters are available. So an inverter with 800 VA will be the right choice for your home.
Know the battery your inverter needs
Battery is the backbone of an inverter system. The performance and life of an inverter largely depend upon the battery quality. The next big question is “how much back up will an inverter provide?” or for “how many hours it can run all of your equipments?”. This is what is called the battery capacity. It is the battery capacity that decides the back up hours. It is expressed in Ah (Ampere Hours).
In the market batteries with capacity of 100 Ah,150 Ah, 180 Ah etc. are readily available. So how to decide which one do you need? To find this out lets do a reverse calculation. Consider that you need a battery that provides back up for 3 hours.
Battery capacity = Power requirement (in watts) * Back up hours ( in hrs) / Battery Voltage (in volts)
Battery Capacity = (535 * 3) / 12 = 133 Ah
** Value of Battery voltage is taken 12V
Therefore a battery with a capacity of 130 Ah will work for you.
So if you want to run 3 fans, 3 tube lights , 1 CFL and 1 TV for 3 hours during power failure you would need 800VA inverter and 130 Ah battery.
By understanding this simple calculation you not only save yourself from the misleading information shared by inverter dealers but also help yourself in taking correct decision.