# How Many Solar Panels are Needed for your Power Requirement - Formula, Example

## How Many Solar Panels are Needed for your Power Requirement - Formula, Example

##### Definition:

Solar panels are used to provide electricity on a small scale.

##### Formula:
Number of Solar Panel = ( ( Total Energy * natural system losses ) / Solar Hours ) / Solar Panel Watts
###### Where,

natural system losses = 1.2 (this factor allows for natural system losses, assuming 85% efficiency) Total Energy = Appliances watts * Appliances usage hours/day

##### Example

If I have 110W tv and it's usage is 5hrs/day, 45W laptop and it's usage is 2hrs/day,and i have 10W solar panel receive 7 hours of sunlight per day. Then how many solar panels are needed?

##### Given:

tv and laptop usage watts and hours Solar Time = 7 Hours/day Solar panel capacity = 10 watts

##### To Find:

Number of Solar panels need

##### Solution:
###### Step 1:

First, let us calculate the Total energy. Total Energy = (tv watts * usage hours/day) + (laptop watts * usage hours/day) Total Energy = (110*5) + (45*2) Total Energy = 550 + 90 = 640W.

###### Step 2:

Substitute the values in the formula,

 Number of Solar Panel = ( ( Total Energy * natural system losses ) / Solar Hours ) / Solar Panel Watts = ( ( 640 * 1.2 ) / 7 ) / 10 ) = ( ( 768 ) / 7 ) / 10 ) = ( 109.714 / 10 ) = 10.9714