220 Ah Battery Backup Time Battery Backup Time Calculation

220 Ah Battery Backup Time – Friends, in this post, we have told you the method / formula to convert the capacity of the battery from Ah to watt. After this, we have shown the backup time of 150Ah battery and similarly calculated the backup time of 200Ah and 220Ah battery.

Different capacity batteries are available for inverters in the market. Its capacity is written on the battery in ampere-hour (Ah). Let us understand in this post that how many Ah battery can give backup for how long on any load. This calculation helps to know the ‘approx’ time. We cannot extract 100% accurate Battery Backup time. First we also learn how to convert battery capacity from Ah to watt, then we will take out the backup time according to the load of our house.

220 Ah Battery Backup Time

Converting Battery Capacity from Ah to Watt

How much energy an inverter battery has the capacity to store, it is written on that battery in the form of ampere-hour (Ah). While the energy needed to run our home appliances is written on them in the form of watts. So first of all let us see how to convert Ampere-hour written on the battery to Watt-hour.

Its capacity is written above the battery, such as 150Ah, 165Ah, 200Ah or 220Ah. Along with this, there is also the voltage of the battery. For home use we mostly run 12 volt batteries on our inverters.

Multiplying the capacity written on the battery in Ah by the voltage of the battery gives us the capacity of the battery in watts (watt-hours).

For example, if we want to find out the capacity of 120Ah, 12volt battery in watts, then-

120Ah x 12v = 1440wh

This means a 120Ah, 12V battery can store a total of 1440 watts of power. While reusing this energy with the help of inverters, we are able to utilize it only up to 80% due to various energy losses. Thus from a fully charged battery of 120 AH we can use about 1150 watts of power.

how long will a battery last on your inverter

The backup time of a battery depends on many factors-

  • on the amount of energy that battery can store
  • on the energy consumption of your home appliances
  • on the efficiency of your inverter battery


That’s why to calculate the battery backup time you need to know the battery capacity, load of your home appliances and efficiency of your inverter battery.

  • The capacity of the battery is written on it in Ah, we can convert it into watt as mentioned above.
  • Talking about the energy consumption of home appliances, generally a fan is 75 watts, an LED bulb is 15 watts. It is also written on other household appliances that how many watts they are.
  • We can generally consider the efficiency of inverter battery as 80% (0.8).

battery backup time

We can calculate the backup time of any battery using the formula given below.

Battery backup = (Ah x volt x efficiency) / load

Ah = This is the battery capacity, which is written on the battery or in the manual that came with it. Such as 100Ah, 120Ah, 150Ah, 180Ah etc.

Volt = This is the voltage of the battery. We usually use 12 V batteries on home inverters.

Efficiency = Efficiency of inverter battery is around 80% (0.8).

Load = Total energy requirement (watt) of those appliances which we have to run on inverter battery.

To calculate the battery backup time, we first calculate the load (consumption) of the equipment we want to run.

If 2 fans and 4 LED bulbs burn continuously in our house, then

2 fans = 150 watt (75 x 2)

4 LED bulbs = 60 watt (15 x 4)

Total load = 150+60 = 210 watt

In this way, if our load is 210W, then now by the formula we can calculate the backup time of any battery on this load.

150 Ah Battery Backup Time

Battery backup = (Ah x volt x efficiency) / load

Battery backup = (150ah x 12v x 0.8)/210 = 6.85 hrs.

Load (watt)approx backup time
150 watt9 hours 30 minutes
200 watt7 hours
250 watt5 hours 45 minutes
300 watt4 hours 45 minutes
400 watt3 hours 30 minutes
150Ah battery backup on different loads
  • The 150Ah, 12 volt battery can provide a backup of about 7 hours at 210W load (2 fans and 4 LED bulbs).
  • Similarly, the backup time of 150Ah battery at different loads is given in the table.

200 Ah Battery Backup Time

  • The 200Ah, 12V battery can provide a backup of about 9 hours at 210W load (2 fans and 4 LED bulbs).
  • Similarly the backup time of 200Ah battery according to the load is given in the table.
Load (watt)approx backup time
150 watt12 hours 30 minutes
200 watt9 hours 30 minutes
250 watt7 hours 40 minutes
300 watt6 hours 20 minutes
400 watt4 hours 50 minutes
200Ah battery backup on different loads

220 Ah Battery Backup Time

  • The 12v, 220Ah battery can provide a backup of about 10 hours at 210W load.
  • The backup time of 220Ah battery at different loads is given in the table.
Load (watt)approx backup time
150 watt13 to14 hours
200 watt10 hours 30 minutes
250 watt8:00 to 8:30 hours
300 watt7 hours
400 watt5 hours 15 minutes
220 Ah battery backup time on different loads

This way you can get the backup time of any capacity battery at any load.

How did you like our post? If you want to know more about battery backup, then comment us on this post from the option given below.

FAQ : Frequently asked questions

How much backup does 135Ah battery give on inverter?

The 135Ah battery can run for approximately 8 – 8:30 hours at 150W load, approximately 6:30 hours at 200W load, approximately 4:20 hours at 300W load or approximately 3:30 – 3:45 hours at 350W load .

How much backup does the 165Ah battery provide?

165Ah, 12V Battery Backup on Inverter approx 10:30 hrs at 150W load, approx 7:45 hrs at 200W load, approx 5 – 5:30 hrs at 300W load or approx 4:30 hrs at 350W load Can give

How much backup does 180Ah battery give on inverter?

The 180Ah battery can run for about 11:30 hours at 150W load, about 8 hours 40 minutes at 200W load, about 5 hours 45 minutes at 300W load or about 4 hours 50 minutes at 350W load.

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