• What is Solar Cell?

• Working Mechanism.

• Why we use Solar Cell?

• P-V System.

• Describe different types of Solar Cell & efficiency.

• What is Solar Lantern?

• How Solar Lantern Works?

• Description of various components of Solar Lantern with diagram.

• Problem

• A structure that converts solar

energy directly to DC electric

energy.

• It is like a battery as it supplies

DC power.

• It is different from a battery in

the sense that the voltage

supplied by the sell changes

with changes in the resistance

of the load.

• Low maintenance, long lusting sources of

energy.

• Non polluting and silent sources of electricity.

• Convenient and flexible source of small

amounts of power.

• Renewable and sustainable power.

• Reduces global warming.

.

• It is very stable with module efficiencies 10%

to 20%.

Mono Crystalline P-V cell

a) It is formed by single cylinder if Si.

b) Operating efficiency up to 15%

a) It is formed by caste ingot of melted and

recrystallised silicon.

b) Cell efficiency=12%

– Silicon deposited in a continuous on a base material such as glass polymer etc.

– It consists of layers about 10 micro meter .

• The most advanced of thin film technologies.

• Operating efficiency—6%.

• Mature manufacturing technologies are

available.

• Initial 20%-40% loss in efficiency.

• It is non-silicon based

technology.

• This cell consists of

Cadmium Telluride(CdTe).

• 6%-9% module efficiency.

• 16% laboratory efficiency.

• The amount of power available from a P-V device is determined by

a) Type & area of the material

b) The intensity of the sunlight.

c) The wavelength of the sunlight.

• Single crystalline cell—25% efficiency.

• Polycrystalline silicon solar cell—less than 20%.

• Amorphous silicon olar cell—less than 10%.

The Shockley-Queisser limit

for the theoretical maximum

efficiency of a solar cell.

Semiconductors with band

gap between 1 and 1.5eV, or

near-infrared light, have the

greatest potential to form an

efficient single-junction cell.

• A solar lantern is a well-known example of portable stand alone solar electric system.

• It consists of all necessary components required for a standalone solar electric system in a single casing except the.(SPV).

• Daily during day time the lantern should be put on charge.

• The 2 pin connector should be connected to the socket at the rear of the lantern.

• Ensure green LED glows.

• Keep the light switch in the off position during charge.

• If the light is switched on during charging, all the charging current from the spv module will be diverted to the lamp and the battery will remain uncharged.

• When the lantern is needed, the connector from spv module is to be unplugged

• The lantern can be carried to the place where it is needed.

• The lamp can be switched ON using the switch provided.

• When lamp switches off and red lamp glows, the light switch should be put off.

• Do not repeatedly switch on the lamp even after the Low Voltage disconnected as this will reduce the life of the lamp as well as the battery .

• Consists of mainly a lamp, a battery and an electronic control circuit in a single casing.

• S.P.Vis a separated part of the lantern.

• Battery, charging and control circuit are placed inside the casing with proper manner.

• The lamp is covered from all sides by transparent glass or fiberglass.

• Hanger of the lantern is filled with the top cover.

Description of Different components

• Solar Module or PV Module::--

a)Used for charging a single solar lantern has rating of 8, 10 or 12 Watts.

b)Normally kept on rooftop at most tilt angle for getting maximum intensity of sunlight.

c)The lanterns are connected to module through wire socket which is kept in room or other places.

• Normally maintenance free sealed dry type

lead acid battery of tabular shaped with 12 V 7

Ah capacity.

• The battery of the solar lantern stores the

energy that is supplied by the SPV Module

during day time.

• Releases it during night time when the light is

required.

• Controls the charging of the battery during

daytime.

• Protects the battery from overcharge or deep

discharge conditions.

• Inverts the D.C energy supplied by the battery

to AC suitable to light the CFL.

• The lamp used in the solar lantern is 7W

Compact Florescent Lamp.

• This lamp is a highly efficient component that

provides light equal to the light given by a

40W incandescent lamp.

• Normally cool white type lamps are supplied.

• WEB-SOL Solar Lanterns come in an elegant

looking plastic housing.

• This also reduces the weight of the system

making it light and portable.

• As the housing is of plastic , there is no

problem of corrosion in coastal and highly

humid areas.

Ans:--

A.C sine inverter taking 24 volt , total Wh will be=124 Wh

Ampere hour /day = 124/24 = 5 Ah

Requirement of initial charge = 3 day(At)

D.O.D = 0.8

DM=20%