Most people want to know how many solar panels do I need for my home, how much capacity the battery is, **how long do solar panel battery las**, how much capacity the inverter is, and many more. In this case, calculation plays a crucial role. In this section, we will let you know how to calculate solar panel systems for your home. Suppose you have a 500-watt load in your home, now how will you **calculate the solar system for your home**? In this case, you have to consider three main things.

- Inverter capacity selection for your load
- Battery capacity selection for your load
- Number of solar panels for your 500 domestic load

**Inverter Selection**

If you have 500 loads, then you have to think of double-time capacity inverter.

However, we have to calculate DC power.

DC power P_{DC }= Voltage (V) * Current (I)

Load 500 watt = 12 volt * I

I = P/V = 500/12

I = 41.6 (A) Amperes (home load current)

**So, if you have a 500-watt load then your running load current is 42 A.**

**Battery Capacity Calculation**

If you would like to select battery capacity, then follow this formula.

Battery capacity = Load * backup time required/Battery voltage

Battery capacity = 500 watt * 12H/12V (if you run for 12 hours)

**Battery capacity = 500 AH**

**So, if you want 12 hours back up then you will require at least 500 AH battery.**

Now, let’s calculate your battery charging current

Battery charging current = battery capacity in AH/charging time (in a day)

Battery charging current = 500 AH/8 hours

Battery charging current = **62.5 Ampere or 63 Ampere**

**So, you should require 63 Ampere for charging your battery (if you require 12 hours’ backup)**

**How Much Current Requires for Solar Panel?**

Finding solar panel current is important to selecting solar panels.

Solar panel current requires = battery charging current + home load current

Solar panel current requires = 63 ampere + 42 ampere = 105 ampere

**Solar Panel Power Calculation Process and Number of Panels Required**

We know that solar panel power P = V * I

Solar panel power P = 14 volt * 105 ampere = 1470 watt

It is noted that when we measure solar panel voltage we measure open circuit voltage and close circuit voltage. The open circuit voltage range is (18 to 21 volts)

On the other hand, close circuit voltage range (14 to 16 volts). We have considered above 14 volts because of the solar panel’s close circuit voltage.

**So if you have 500-watt load demand then you require a 1470-watt solar panel for 12 hours back up**

**There are many ****wide ranges** of **solar panels** such as 145-watt, 190-watt, 390-watt, 440-watt**, etc.**

**Solar Panel Price in Bangladesh**

So, let’s figure out **how much solar panel cost for my house**. If the solar panel price is 50 BDT per watt then you require = (1470 * 50) = 73, 500 BDT (only solar panel cost for 12 hours back up)

If you need 6 hours back up, then you require = (735 * 50) = 36750 taka (only solar panel price). It is noted that the **average cost of solar panels** can be different in varying countries.

** Final Thought**

We all know that solar energy is the cleanest and most renewable energy in the world. If we can use them instead of natural energy, then it would be the best way for our future. But the cost is a major impact to install solar systems. It is true that to **install a solar system** at home you have to count a big amount. Suppose you want to install a solar system to meet a 500-watt load then you have to think about the high cost. But if you think about sustainability this cost is nothing. In this case, you can say **how long solar panels last**. Solar panels last 25 to 30 years. However, let’s try to install solar panels in our homes to get renewable and clean energy.