Page 89 - GRIHA Manual Volume III - Introduction to National Rating System
P. 89
82 GRIHA Manual: Volume 3
Figure 3 Classiication of various types of solar cells
# Shading: Shading has a detrimental impact on the performance of SPV systems. Even partial
shading can drastically reduce the solar panel output, and if it persists, may even damage the
whole system.
# Other effects: Dirt and dust accumulating on the surface of the panels results in reduction in the
amount of incident solar radiation. This can lead to reduction in power generation. Mismatching
of modules in a string, resistance of wires and cables, and so on also have a significant impact
on the performance of SPV systems.
2. Battery: The most important parameter of a battery is its capacity that is measured in ampere-
hour (Ah). Battery capacity is a measure of the energy that can be extracted from the battery.
For SPV applications, mostly lead-acid batteries are used, especially for applications where
deep discharge is required. Deep cycle batteries are designed to be repeatedly discharged by
as much as 80% of their capacity. For example, a 100 Ah battery can repeatedly be discharged
upto 20Ah. There are different types of lead-acid batteries available like lead-acid batteries
with seals or without seals, VRLA-Gel (valve regulated lead acid-gel) batteries, and others.
The capacity of a battery is related to the following.
• Discharging current: The higher the discharging current, lower the capacity and vice
• versa. o
Temperature: For temperature below 25 C, battery capacity reduces by about 0.6 %
o
• per C.
Life of the battery: Higher the frequency of charging/discharging for a battery, shorter is
its life. Similarly, the deeper the battery is discharged, shorter is its life.
3. Charge controller: A PV system generates electricity during the day when there is abundant
sunshine. Thus, the battery can get over charged. However, during night, the battery can
get discharged as the PV system is not generating electricity. The states of overcharged and
discharged both have a huge negative impact on battery life. A PV charge controller protects
the battery from these situations. A PV system charge controller works by automatically
disconnecting the PV module(s) once the battery is fully charged, thus, preventing it from
getting overcharged. Also, when the battery’s charge is very low, the charge controller
Figure 3 Classiication of various types of solar cells
# Shading: Shading has a detrimental impact on the performance of SPV systems. Even partial
shading can drastically reduce the solar panel output, and if it persists, may even damage the
whole system.
# Other effects: Dirt and dust accumulating on the surface of the panels results in reduction in the
amount of incident solar radiation. This can lead to reduction in power generation. Mismatching
of modules in a string, resistance of wires and cables, and so on also have a significant impact
on the performance of SPV systems.
2. Battery: The most important parameter of a battery is its capacity that is measured in ampere-
hour (Ah). Battery capacity is a measure of the energy that can be extracted from the battery.
For SPV applications, mostly lead-acid batteries are used, especially for applications where
deep discharge is required. Deep cycle batteries are designed to be repeatedly discharged by
as much as 80% of their capacity. For example, a 100 Ah battery can repeatedly be discharged
upto 20Ah. There are different types of lead-acid batteries available like lead-acid batteries
with seals or without seals, VRLA-Gel (valve regulated lead acid-gel) batteries, and others.
The capacity of a battery is related to the following.
• Discharging current: The higher the discharging current, lower the capacity and vice
• versa. o
Temperature: For temperature below 25 C, battery capacity reduces by about 0.6 %
o
• per C.
Life of the battery: Higher the frequency of charging/discharging for a battery, shorter is
its life. Similarly, the deeper the battery is discharged, shorter is its life.
3. Charge controller: A PV system generates electricity during the day when there is abundant
sunshine. Thus, the battery can get over charged. However, during night, the battery can
get discharged as the PV system is not generating electricity. The states of overcharged and
discharged both have a huge negative impact on battery life. A PV charge controller protects
the battery from these situations. A PV system charge controller works by automatically
disconnecting the PV module(s) once the battery is fully charged, thus, preventing it from
getting overcharged. Also, when the battery’s charge is very low, the charge controller
