Nickel-cadmium (Ni-Cad) batteries are secondary, or rechargeable batteries, and have several advantages over lead-acid batteries that make them attractive for use in stand-alone PV systems.
Why do solar PV systems need batteries?
Batteries: Fundamentals, Applications and Maintenance in Solar PV (Photovoltaic) Systems In a standalone photovoltaic system battery as an electrical energy storage medium plays a very significant and crucial part. It is because in the absence of sunlight the solar PV system won't be able to store and deliver energy to the load.
It is desired that batteries used in the solar PV system should have low self-discharge, high storage capacity, rechargeable, deep discharge capacity, and convenience for service. For such a requirement the lead-acid batteries are widely used for the PV application.
The charge storage capacity of the battery is reflected by its physical size. Small size batteries have small storage of charge while large size batteries have high storage of charge. One of the most commonly used batteries in the solar PV system is the lead-acid battery.
Such rechargeable batteries with many cycles are widely applicable in solar PV applications as they ensure the continuity of the power to the load in the presence of low or even no sunlight, without which the implementation of a standalone solar PV system would be very unreliable and difficult.
How to choose a battery for a PV system?
Batteries with a large charge-discharge cycle are the most suitable for the application of a standalone PV system. Other factors that add up to the selection of the battery are the cost and availability of the batteries. Before choosing a battery, we need to make sure its availability in the market.
Do solar panels need a battery?
Energy requirements for producing PV modules have been studied and debated since the early 1970s, while batteries have gained less attention. In a study of solar home systems, Alsema concluded that lead–acid batteries contribute significantly to the energy requirements.