E 
Daily energy requirements 

Wh/day 
(Calculated above) 
i 
Isolation 

KWh/m2 per day 
(Solar Irradiance, the effective amount of full sunshine per day) 
epv 
Power point efficiency 

% 
(Efficiency of the solar panels  80% for normal regulator, 90% for MPPT) 
ebat 
Charge cycle efficiency 

% 
(Efficiency of the batteries  5% loss) 
S 
Array size in peak Watts 

Wp 
(The amount of solar power needed to generate the amount of electricity used in one day) 
Cost per Watt 

USD 

Estimated cost for solar panels 

USD 
(Total watts required multiplied by cost per watt) 