How to calculate Solar Panel, Battery and Inverter?

When you plan to install solar panel, battery and inverter, then you must be wondering about how to decide the capacity of these components. On the basis of our practical experience, below guide will help you.

Step 1: Load Calculation

The best way to calculate load calculation is to use best quality clamp meter. Let’s assume for this calculation we will use a clamp meter that will support 600A . Using this clamp meter, we can calculate power consumption of home, office, shop, school, medical clinic, & petrol pump, etc. Follow the below steps to Calculate the power consumption:

1. Turn on all the appliances
2. Use clamp meter in phase wire of electric meter

While you use clamp meter, it shows power consumption in Amp. Such as 5Amp, 10Amp, & 20Amp, etc. Indian grid voltage range starts from 220V-240V. But you must check voltage as well using this clamp meter.

Load Calculation = 220V * 5 A

                             = 1100W

Step 2: Backup Time

In above steps, I have calculated the power consumption. On the basis of this calculated power consumption, we should know how many hours you may want to run appliances after power cut. If your answer will be 4 to 5 hrs. That means:

Battery Storage = Total Load * Backup Time

                          = 1100W * 4 hrs.

                          = 4400W

Also read: How to Calculate Inverter Battery Backup Time?

Step 3: Battery Capacity

In above steps, You will know about your required battery storage. There are two types of battery technology in India – lead acid battery & lithium battery. In lead acid battery, 150Ah lead acid battery is the most popular battery for homes and businesses. One 150Ah battery stores 1300 Watt. That means, you need

Battery Capacity = Required Battery Storage / Battery Storage

                            = 4400W / 1300W

                           = 4 Batteries

Generally, 4 batteries of 150Ah comes in 48V.

In case of lithium battery, you need only one battery that comes with 5kWh, 48V.

Also read: How to Calculate Battery Capacity for Inverter?

Step 4: Inverter Capacity

In above steps, you will know both the battery capacity and voltage. According to battery voltage, capacity, and power consumption. In simple language, I need here a 48V & 5kW inverter.

Inverter Capacity = Load  + Load * 20%

                             = 1100W + 1100W * 20%

                             = 1100W + 220W

                             = 1320W

That means, you need around 1.3kW inverter capacity.

Step 5: Solar Panel Capacity

Finally, you need to calculate the solar panel capacity. We always know that solar panels generates DC voltage (22V to 50V). In simple terms,

Solar Panel Capacity = 3 * Battery Capacity

                                  = 3 * 600Ah

                                 = 1800Watt

That means, you need 1.8kW capacity of solar panels and the highest wattages of solar panels in India is around 540W. If you choose these solar panels, then you will need around 4 solar panels for charging your battery as well as run your home loads.