Are you planning to purchase a new AC to DC power inverter or upgrade your old one? Whatever may be the case, it is very vital to KNOW what the right inverter for your home is before purchasing. The total power requirement at your home can be very different from your neighbor’s home. So do not buy the same inverter (in terms of power) and blindly install it in your home. Before purchasing an inverter for your home do a little homework and understand the basics.
At the end of this article, you will know how to determine the right inverter and battery for your home when purchasing one.
What you need to know before purchasing any of the inverter or battery
First understand your Power Requirement
One of the most crucial factors that you must know before purchasing an inverter is your “Power requirement” at home. That is all the electrical appliances (like a fan, CFLs, television, LEDs bulb etc.) you want to use at the time of power failure. The total power requirement is the addition of the individual power consumed by various electrical equipment.
For example, you want 3 Fans, 4 CFL, 3 LEDs bulb & 1 television to function at the time of power failure. Below is the power consumed by each of these items:
1 Fan – 75 Watts
1 CFL – 40 watts
1 LEDs bulb – 13 watts
1 Television – 120 watts 225 120 26
Therefore the total power requirement is ((3×75) + (4×40) + (3×13) + (1×120)) = 524 watts
Find the volt-ampere(VA) rating of the inverter you need
what is volt-ampere(VA) of a power inverter?
The volt-ampere is the voltage and current supplied by the inverter to the electrical equipment. If an inverter works with 100% efficiency, then the total power requirement of the electrical items and power supplied by the inverter will be the same. However, it remains a fact that 100% or ideal conditions do not exist in real life.
The efficiency range of most inverter is from 60% to 80%. This efficiency is also known as the power factor of an inverter and is simply the ratio of the total power required by all the appliances to power supplied by an inverter. The power factor of most inverters ranges from 0.6 to 0.8 as already stated above.
Therefore, Power supplied (or VA rating of the inverter) = the total Power requirement ( power consumed by equipment in watts) / Power factor( efficiency).
Here the average value of power factor or efficiency is considered to be 0.7
Power of inverter (VA) = 524/0.7 = 749 VA
In the market, you can purchase 800 VA inverters. Therefore, an inverter with 800 VA will be the appropriate choice for your home.
Know the battery your inverter needs
Battery is the main component of the solar electric system. The functionality and life of an inverter largely depend upon the battery quality. The next thing to know is “how much back up time will an inverter provide?” or for “how many hours can the inverter power your entire power requirement that is electrical equipment?” This is what is known as the battery capacity. It is the battery capacity that determines the backup hours. It is expressed in Ampere Hours (Ah).
In the market, there are batteries with a capacity of 100 Ah, 150 Ah, and 180 Ah 200 Ah, etc. readily available. So how to decide which one you need? To know this, let’s do a reverse calculation. Assuming that you need a battery that provides back up for 3 hours.
Battery capacity = Power requirement (in watts) x Back up hours (in hrs.) / Battery Voltage (in volts)
Battery Capacity = (549 x 3) / 12 = 137.25 Ah
Note the 12V is the Value of Battery voltage
Therefore, a 150Ah battery capacity will work for you.
Therefore, if you want to use 3 fans, 4 CFL, 3 LEDs bulbs, and 1 TV for 3 hours during a power failure you would need 800VA inverter and 150 Ah battery.
By understanding this simple calculation, you save yourself from the misleading information shared by dealers of inverter and battery and it will help you in taking correct decisions.
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