I will elaborately discuss the facts to choose a inverter in the following steps
1) calculate the load. example: ceiling fan - 60 w, tube light - 40 w, Old television - 80 w, computer - 90 w, CFL(printed on label or box)
2) don’t add all the load at once, add load only you use simultaneously .
example:
3 tube light(340=120)w+ 3 ceiling fan(360=180)w+CFL(18w)+ television(80w)= 398W
or
1 tube light(40w)+ 1 ceiling fan(60w)+CFL(18w)+ television(80w)= 198W
maximum load - 400 watts(approx)
minimum load - 200 watts(approx)
3) our max requirement is 450 watts
inverter load techniques - VA x Power Factor(80%)= Total Power(watts)
inverter VA rating -Max Power - Min Power
600 VA - 400 W -100 W
800 VA - 600 W -130 W
1000 VA - 800 W -150 W
These values are more than enough for home purpose. always remember
~high power ups+ low power consumption= inefficient batt discharge+ waste of money
~low power ups+ high power consumption= quick batt discharge(low batt life)+ overload inverter
~ correct Power ups+ proper batt= good batt life+ saving
choose any top brand inverter with any battery.
4) battery life: all batteries should be charged to full battery condition and discharged to somewhere below half power. these will increase battery life. make sure enough distilled water in each compartment of battery. now a days compartment caps have water level indicators which should not go below red mark.
If water in any compartment dries quickly contact a professional or service person immediately.
Never add too much water in battery as the acid percentage will go low which reduces batter back up time.
600 VA inverter - 100 AH to 150 AH
800 VA inverter - 100AH(for low power) -130AH(medium power) - 150AH(High power)
1000VA inverter - use 150 AH or above
5) Don’t waste your money to buy high power battery
800 VA inverter with
-100 AH battery will give back up 5 hours in low load(120 W) & 2 hours in high load(400 W)
-150 AH battery will give back up 6 hours in low load(120 W) & 2 hours 30 minutes in high load(400 W)
These are some steps to be followed before choosing your ups. Hope u guys like them.