Choosing a right Inverter and Battery for Home

DIFFERENCE BETWEEN UPS AND INVERTER
Inverter is an electronic circuit for converting Direct Current DC to Alternating Current AC. They are used in a wide range of applications from small switched power supplies to large electric utility applications to transport bulk power (like Computers,TV's,  A/c's,Fridge, Mixier and Grinders etc.)

A UPS typically includes the battery and battery charger in one stand alone unit, especially used for computer backups. UPS will effectively switch from utility power to its own power source almost instantaneously.

WAVES - SQUARE WAVE, SINE WAVE AND QUASI SINE WAVE
Square Wave Inverters
Simplest and least expensive in the market. Computers, televisions, induction motors, transformer loads and even light bulbs are not recommended to run on this waveform, because square wave has a high harmonic content.
Sine Wave Inverters
This is the correct waveform on which all electronic equipment, televisions, and computers are designed to run. They filter the output voltage well and recommended.
Quasi-Sine Wave Inverters
Indeed correct selection for running some types of motors and incandescent lighting and not fit for all types of equipments, hence it is not recommended.

CALCULATE YOUR POWER CONSUMPTION
This can be done by adding up the watts on the equipment specifications normally printed below or behind the equipments.

I selected 800 VA which delivers approximately 640 watts. Don’t select very high inverter than the requirement as it will consume more electricity and loss of power is also higher.
CHOOSING THE INVERTER
After calculating the consumption the next step is to select the Inverter VA.

The formula is
Watts / Power Factor = VA
For me it was
542 Watts / 0.8 Power Factor = 677 VA
(Power Factor: 0.8 for most of the UPS, incase of APC Inverters the power factor is 0.6, you can refer product manual or ask dealer for this info)

So the available VA’s in market are 500 VA, 800 VA, 1000 VA, 1400 VA and above. I selected 800 VA.

CHOOSING INVERTER BRAND
This was quite difficult. I selected few known brands in market like Luminous (widely advertised in 2004), Genus (OEM supplier for LG and Samsung), Su-Kam (From few years they are in the market, but most advertised), Hyundai (New, manufactured by Luminous under license from Hyundai Korea), Microtek (Addidas group) and APC (New to Home Inverter).

CHOOSING BATTERY SIZE
Batteries are available in various Amperes. You need to decide how much backup you require and decide on the amperes.
Here is the formula to calculate the backup
Load/Voltage x Backup hours = Amperes
In my case it was
542 Watts / 12 V x 3 hrs = 135 Ah
I selected 130 Ah Standard Furokawa battery for my home.

CHOOSING BATTERY
Battery is a backbone for any inverter. There are different types of battery available in the market.

Maintenance battery
These batteries requires maintenance every month. The distilled water needs to be filled every month.

Maintenance free battery
This comes with flat plate collectors and maintenance free. These batteries will have a life of 4 years.

Tubular batteries
Here the active material (lead oxide) is encapsulated in polyester tubes to prevent ‘Shedding’. The electrode geometry facilitates ‘cyclic’ deep discharges. They are recommended for back up power for UPS and Inverters where environmental conditions are tough and high ambient temperatures are common. These are capable of long hours of backup.

CHOOSING THE DEALER
I was looking for a branded inverter which is in the market from a long time and providing good service. Price was the second priority, however I and my friend did a good analysis to get best deal. We validated almost 5 Inverter vendors and battery vendors.  This dealer is dealing in the market from a long time and have many clients who are satisfied with their service. They also gave price assurance. They assured they will return back the difference if we bring a quote lower than what they offered. What else we need, we went ahead.

The prices were as below (as on Apr 2007)
Inverters
Genus / Hyundai / Sukam / Mikrotek / Luminous - 800 VA: Rs.6000.00
Genus / Hyundai / Sukam / Mikrotek / Luminous - 1400 VA: Rs.7000.00
APC 800 VA with AMCO maintenance free battery – Rs.12,925.00
Batteries
Standard Furokawa 130 AH Tubular Battery: Rs.9500.00
Exide EL 120 AH Tubular Battery: Rs.9500.00

USEFUL WEBSITES
Luminous - http://www.myluminous.com/
Genus - http://www.genusoverseas.com/
Sukam - http://www.su-kam.com/
APC - http://www.apc.com/

Exide Battery - http://www.exideindustries.com/
Online Exide Battery shopping (Expensive, you can know the current market price) - http://www.bizrate.com/
Amaron Battery - http://www.amaron.in/