How to Calculate Battery Capacity for Inverter?

Size of battery can be estimated based on actual connected load and required backup hours. Battery rating defined with Ampere Hours (AH). Please visit loom solar for detail battery size calculation.

Battery Capacity Calculation Formula:

Battery Capacity = Inverter Capacity & Voltage

The charging current is set in the battery. It is very important to know how many Amp's charger to charge. Each inverter has a given rating of charge. If we charge the small battery with the charger of maximum rating, then the layer of lead which remains on the battery cell will heat up and fall in the battery and the battery will get damaged. When the battery is bad, the backup will stop giving and the battery will not start charging. Therefore, the capacity of the battery is selected according to the capacity of the inverter.

Case 1: Commercial Establishment

In January to March month, power consumption of any commercial places, such as office, shop, school, clinic & hospital, etc. the maximum power consumption is 40% - 50% compare than summer season (April to September). When we plan to install inverter battery, we must know annual power consumption.

Step 1: Calculate Continous Load

For example, we are taking an example of one office whereas 50 laptops, 2 desktop, 50 ceiling bldc fans, 60 lights, internet, router, mobile charging, 1 refrigerator, 1 water cooler, 1 printer, and 1.5 ton split inverter ac, and some other lights. During the summer season month of April, the maximum power consumption is 4500 watt whereas during the winter season month of January, the maximum power consumption is 1500 to 2000 watt.

Step 2: Decide Inverter Capacity

Based above power consumption, we have selected 5kVA inverter and this inverter comes in 48V. According to battery capacity calculation formular, we need here 48V battery.

How many hours backup required? In case of commercial establishments, the maximum power cut duration is up to 2 hrs. but it is frequent power cut. The power cut duration might be 5 minutes, 10 minutes, like this. The purpose of installing power backup solution in commercial areas to give uninterpreted power supply to run commercial activities.

Step 3: Think about Power Cut in your area

According to continuous load and backup time, we need 9000 watt hour battery bank. If you select 150Ah lead acid battery, then you need 6-7 batteries and if you select CAML 100Ah lithium battery, then you need 2 batteries.

Case 2: Residential Places

The same scenario in residential homes but home appliances are different. The basic appliances of any homes, such as lights, fans, tv, washing machine, refrigerator, water sump (surface pump / submersible pump), internet, laptop, power socket, iron press, air conditioner (normal ac or inverter ac), and more. The regular power consumption of any home is 300 - 400 watt, but maximum power consumption 1500 – 2200 watt of any 3 BHK homes.

If any home owner wants to run only basic appliances such as fans, tv, light, internet, refrigerator, and power socket, then he needs 1kW inverter and this inverter comes in 24V. Based on this inverter voltage calculation, he need 2 no. of 150Ah lead acid battery. If he run 400 watt loads on home, then it can give 6-7 hrs. backup time.

If any home owner wants to run basic appliances as well as heavy appliances such as water pump, air conditioner, washing machine, dish washer, induction, and more, the he need 3kW inverter and this inverter comes in 48V. Based on this inverter voltage calculation, he need 4 no. of 150Ah lead acid battery. If he wants to install the latest technology battery, then he need 1 no. of CAML100 lithium battery. If he runs 2000 watt load, then it can give 2 hrs. backup time.

Note: The backup time can vary depending on power consumption, so above guide is only for your idea.

हिंदी में पढ़ें: कैसे लगाएं Inverter के लिए Battery Capacity का अंदाजा?

1 comment

Rajnikant Hirji Pabari

Rajnikant Hirji Pabari

We have 1750 sq feet 4 bed 1 hall 3 bath and kitchen
We once a week have 6 hrs power cut
We need to run 1 ac 1.5 ton 1 freez freezer 405 lit 4 fans and 6 lights
Please advise what size inverter and how many dry cell (no water) battries We need

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