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Solar Panel Installation: Step by Step Procedure with calculation and examples

Before we start , its recommended to read the article about proper selection & different types of solar panels and photovoltaic panel for home & commercial use as well.

Now lets begin,

Suppose, we are going to install a solar power system in our home for a total load of 800W where the required backup time of battery is 3 hours (You may use it your own as it is just for sample calculation)

Load = 800 Watts

Required Backup time for batteries = 3 Hours

What we need to know?

1. Inverter / UPS Rating =?

2. No of batteries for backup power =?

3. Backup Hours of batteries =?

4. Series or Parallel Connection of Batteries = ?

5. Charging Current for Batteries = ?

6. Charging Time for batteries = ?

7. Required No of Solar Panel =?

8. Rating of Charge Controller = ?

Solution:

Inverter / UPS Rating:

Inverter / UPS rating should be greater than 25% of the total load (for the future load as well as taking losses in consideration)

800 x (25/100) = 200W

Our Load + 25% Extra Power = 800+200 = 1000 Watts

This is the rating of the UPS (Inverter) i.e. We need 1000W UPS / Inverter for solar panel installation according to our need (based on calculations)

Required No of Batteries

Now the required Back up Time of batteries in Hours = 3 Hours

Suppose we are going to install 100Ah, 12 V batteries,

12V x 100Ah = 1200 Wh

Now for One Battery (i.e. the Backup time of one battery)

1200 Wh / 800 W = 1.5 Hours

But our required Backup time is 3 Hours.

Therefore, 3/1.5 = 2 → i.e. we will have to connect two (2) batteries each of 100Ah, 12V.

Backup Hours of Batteries

If the number of batteries are given, and you want to know the Backup Time for these given batteries, then use this formula to calculate the backup hours of batteries.

1200 Wh x 2 Batteries = 2400 Wh

2400 Wh / 800 W = 3 hours.