Page 307 - Electrician - TT (Volume 2)

ELECTRICIAN - CITS

Basic idea of a solar module, array and balance of system (BOS)
Module
Solar cells are made in various shapes and sizes. The smallest of the cells can be seen in devices like an ordinary
calculator, these type of devices are very little amount of power used in home lighting system needs more power
to run on. The number of cells are put together to produce more power. The group of cells is packaged together
in an enclosed space is called as a module.
It helps to give higher voltage, high power and protects the panel from rain, snow and wind etc. voltage and power
output of module depend on the size and number of cells used. So, more number of modules are to be connected
in a simple assembly of modules is known as array. (Fig 2)

Fig 2

Balance of system (BOS)
The cells modules and arrays are the power producing part, a small devices like radio, needs a small amount of
power, can be directly connected to a small module. But most of the devices appliances need more power at
night. The assembly of module, battery and an appliance is simple form a P.V system.
A module cannot be connected directly to a battery, so, a charge controller on charge regulator is used in between
module and battery and inverter are required to operate AC appliances. So, the whole system excepts the
module is known as balance of system (BOS). (Fig 3)

Fig 3

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CITS : Power - Electrician & Wireman - Lesson 106-116