The system is used in places where there is no access to electricity. Electric current is generated from solar panels when sun light falls on it. This current is stored in the battery for later use. DC appliances are generally used in SHS systems for better efficiency. However, inverter is included for powering AC appliances

Functions of different components

Solar panel:Converts sun light into electric current. Rated in terms of peak watts produced. Apex stocks panels from 10Wp to 185Wp (70WHr to 1,295WHr @ 7 Hr Irradiance). For higher requirement, multiple panels are used which are connected in combination of parallel and series connections.

Solar charge controller: Regulates charging and discharging of the batteries to optimize the ‘retained charge’ of the batteries and maximize the life of the batteries. Apex stocks controllers from 3Amps to 140 Amps (PV current or Load current). Parallel connections of controllers for higher capacities is possible by using current sensors in the loop of master-slave combinations. For SHS system with 1 panel, a controller of 12 Amps is sufficient.

Batteries: Reservoirs of charge current that is being produced by solar panels, batteries are connected in combination of series or parallel to match the system voltage. Apex stocks batteries from 7Amps to 415Amps in different voltages.

Inverters: DC (12V/24V) loads are connected straight to the controller. However, AC loads needs conversion of DC into AC which is done by an inverter. It is recommended nevertheless to connect inverter to the controller if load is not very high.

Reliability: All the components in the SHS are extremely reliable. Solar panel usually has a life of over 30 years (crystalline types). Inverter and charge controllers are also very reliable. Batteries being deep cycle type would typically last 4-6 years after which they need replacement.

Viability: A typical SHS producing 500WHr output costs about USD 700.00. You can typically power DC lamps*, DC Fans* and DC TV* with this system. You can run your house of with 4 lights and 2 fans for over 9 hours. DC TV*, if added to the load, can run for 2 hours but reducing the duration of lights and fans to about 7 hours.

*Components are of energy saver types. Apex has a ready stock of most of these components.