jremington:

Batteries are not measured in Watts, they are measured in Volts and Ampere hours.

7740 Watts is enough power to **heat a small building**, so check your calculations.

Yes the example I found the person was referring to watt. I’m not sure why as I also found it odd.

I revisited my earlier calculations and tried again and shown below are my new values:

Variables:

- System power usage = 835.1mA
- Solar energy for my location = 1100kwH/m^2
- Hours in 1 Month = 730h / 31 Days = 744h
- Hours in 1 Year = 8760h
- Solar Panel efficiency = 15.5%

1st Calculation:

1100kwH/m^2 / 8760h = 0.126mW/m^2 * 1000 = 126w/m^2 ← Total solar radiation for 1 year

2nd Calculation:

126w/m^2 / 12 = 10.5w/m^2 ← Total Solar radiation for 1 month

3rd Calculation:

10.5w/m^2 * 0.155 (15.5%) = 1.63 W/m^2 ← produced by the solar cell

4th Calculation:

1.63w/m^2 / 10 = 0.163mW/cm^2 ← converted into milliwatts per cm^2

5th Calculation:

835.1mA / 1000 = 0.8351 Amps

6th Calculation:

5.00v * 0.8351 = 4.18w

7th Calculation:

4.18w / 1.63w/m^2 = 2.56cm^2 ← Size of solar panel needed

8th Calculation:

744h * 0.8351 = 634.71

9th Calculation:

634.71 * 2 (some rule of thumb apparently) = 1269.42 ← Battery capacity ?

10th Calculation:

1269.42 / 835.1 = 1.52 ← hours run time ?

Sorry for the long post, I imagine this probably makes little sense and unfortunately I miss placed the source when I got the calculations method from.