The document provides an overview of standalone solar electric systems, which use solar energy as their primary power source and operate independently from the electrical grid. It details different types of standalone solar systems, including those with only DC loads and those that include storage batteries and inverters to support both AC and DC loads. Practical applications such as solar lanterns and solar street lights are highlighted, emphasizing their utility in remote areas without access to traditional electricity sources.

1. Presented by
Dr. R. RAJA, M.E., Ph.D.,
Assistant Professor, Department of EEE,
Muthayammal Engineering College, (Autonomous)
Namakkal (Dt), Rasipuram – 637408
MUTHAYAMMAL ENGINEERING COLLEGE
(An Autonomous Institution)
(Approved by AICTE, New Delhi, Accredited by NAAC, NBA & Affiliated to Anna University),
Rasipuram - 637 408, Namakkal Dist., Tamil Nadu, India.
What is Standalone Solar Electric System?

2. What is Standalone Solar Electric System?
 The system which utilizes only solar electric energy as main source of energy is
referred as standalone solar electrical system.
 There are many locations on this earth where no source of electricity is
available. At these locations standalone solar electrical system can be the ideal
source of electricity.
 The main advantage of this system is that it does not depend on grid or any
other source of electricity.
 As it does not have any connection with grid or other electric supply line, it is
also known as off-grid Photovoltaic system.
 As the sun is the only source of energy in this system it should have some
means to make it active even in night times.
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3.  A storage battery system does the job. Therefore, a storage battery system is an
essential component of standalone solar system.
 But, often this battery system can be omitted from the system if the system is
dedicated for the load which to be operated in day times only.
 Popular examples of standalone solar system are solar lanterns, solar home
lighting systems, solar water pumping systems, etc.
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4. Types of Standalone Solar Systems
 Depending upon the use and design there are different types of standalone solar
systems.
 Standalone Solar (PV) system with only DC load
 Standalone Solar (PV) system with DC load and Electronics control circuitry
 Standalone Solar (PV) system with DC load, Electronics control circuitry and
Battery
 Standalone Solar (PV) system with AC/DC load, Electronics control circuitry
and Battery.
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5. Standalone Solar (PV) System with only DC Load
 This system is simplest among all the standalone solar system. Standalone Solar
(PV) System with only DC Load requires only two main components one the
solar module array where the electricity is generated and one or more DC loads
where the electricity is consumed.
 This system serves only during sunny day times. The configuration of this
system is quite simple as we told earlier here the solar module array is directly
connected to the load no other arrangement is required in between.
 It is quite natural that the rate of production of electricity in this system varies
throughout the day depending upon the intensity and incidence angle of the
sunlight.
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6.  This makes the applications of Standalone Solar (PV) System with only DC
Load limited to some specific electrical appliances where the precise operation
is not essential.
 This standalone solar system can be successfully utilized for pumping drinking
and irrigation water as in these both cases fixed amount of water is not required
to lift every hour.
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7.  DC fan can be operated by this system when speed of the fan is not required to
be constant throughout the day.
 In this system the speed of the fan is maximum when the intensity of sunlight is
maximum.
 Hence, maximum pleasant air flow is achieved during maximum hot period of
the day times.
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8. Standalone Solar (PV) System with DC Load and
Electronic Control Circuit
 Standalone Solar (PV) System with only DC Load can be improved by adding
an electronic control circuit.
 This added electronic control circuit to the system, improves the utilization of
power generated by the solar module array.
 This electronic control circuit is normally an electronic solar charge controller
(SCC) (voltage or current regulator) or a maximum power point tracker
(MPPT).
 The main purpose of these circuits is to provide regulated current and voltage to
the load. The MPPT circuit is used to extract maximum power from the solar
modules under all conditions.
 Thus, it ensures the best utilization of solar PV modules.
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10. Standalone Solar (PV) System with DC Load, Electronic
Control Circuit and Battery
 A standalone system can be more practical and usable if it is able to serve even
in absence of sunlight that is in night times.
 This can be simply done by adding a storage battery in the system which stores
electricity produced during day times.
 This stored electricity can be utilized when there is no sunlight and in night
times. After adding a suitable rated battery, the system becomes a Standalone
Solar (PV) System with DC Load, Electronic Control Circuit and Battery.
 It is needless to say that this standalone system has four basic components.
1. Solar Module Array
2. Electronics Control Circuit
3. Storage Battery System and
4. DC Load
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12.  Here solar module charges the battery during daytimes and the battery supplies
the load both during day and night.
 The electronic control circuit plays a vital role here it actually controls the flow
of charges into the battery and out of the battery depending upon the system
conditions and demands.
 The control circuit also protects the battery from overcharging as well as over-
discharging.
 This system is most commonly used in solar street light system in remote
villages. LED based solar lanterns which nowadays widely available in the
local market are popular examples of Standalone Solar (PV) System with DC
Load, Electronic Control Circuit and Battery.
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13. Standalone Solar (PV) System with AC/DC Load,
Electronic Control Circuit and Battery
 So far we have discussed about the standalone solar energy systems which can
only be used for operating DC load but maximum numbers of equipments we
use in our daily life are AC operated so some means is required to attach with
the solar energy system so that we can run AC equipment as well with
standalone solar system.
 Inverter is a device which converts DC to AC of specified voltage and
frequency. Inverter is basically a DC to AC converter whose input is DC and
output is AC of desired voltage and frequency.
 So if we connect an inverter across the DC output terminals of electronic
control device along with the DC load then the system becomes able to run AC
equipments as well.
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14.  As this system can operate both DC and AC load, the system becomes most
popular version of standalone solar energy system.
 Nearly all kinds of DC and AC load can be operated by this system such as
AC/DC fan, computer, TV, tube lights, CFL, LED lamps etc.
 This system is most suitable as alternative of grid electric supply where limited
grid electric supply is available.
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16. It is needless to say that this standalone system has six basic components
 Solar Module Array
 Electronics Control Circuit
 Storage Battery System and
 DC Load
 Inverter
 AC Load.
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17. Thank You
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