Solar pv battery storage – understanding the basics

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Solar power generation and energy storage go hand-in-hand. Both commercial and residential solar panels fluctuate their electricity output, depending on the intensity of prevailing solar radiation. Normally, solar PV energy peaks between noon and late afternoon when the sun shines brightest, and drops during cloud cover and dusk. A solar battery system stores the surplus electricity produced during the daylight hours for later use.


Solar generators mostly use deep-cycle batteries. Unlike regular batteries, these are designed to discharge slowly over a long period and can be recharged thousands of times. Solar batteries are rated in Ampere Hour (Ah), indicating the battery’s capacity and discharge rate. For instance, a “100Ah at a 100hr rate” means the battery can supply a steady 100 Amperes current for 100 hours.

Solar PV batteries come in various sizes, capacities and discharge rates. They’re also built using different technologies to achieve the desired performance goals and price points.

Lead-acid batteries

These are the most common and widely available solar batteries. Lead-acid batteries are the same type used in vehicles and other machinery applications. They are relatively inexpensive but also bulky, maintenance-intensive and have a low tolerance to deep-cycles. They can last anywhere between 3-10 years, depending on the build quality and usage.

Lithium-ion batteries

Lithium-ion batteries were first used in portable devices — smartphones, laptops, tablets, cameras, etc. They’ve only recently made it to the solar PV market, thanks to advancements in battery technology and manufacturing processes. Unlike lead-acid batteries, Li-Ion batteries are dry, lightweight and compact, low-maintenance, highly tolerable to deep-cycles and have a high energy density. However, they are more expensive, and their manufacture and disposal pose real threats to the environment.

Saltwater batteries

The saltwater battery is a newcomer in the energy storage business. Although the technology is unproven in the mainstream solar market, it shows great promise as a greener, cheaper energy storage solution. Unlike the other two battery types, these rely on saltwater electrolytes to store power instead of heavy metals such as lead, cobalt and lithium.

Why do you need a solar PV battery system?

Solar PV batteries work by chemically storing the DC electricity generated by solar panels. The battery acts as a buffer for low-voltage DC loads and the AC inverter. More importantly, a battery pack is a power backup. A robust battery system can supply an average household with enough power for up to three days without a recharge. In short, a solar PV battery is crucial in maintaining a stable and dependable power supply from a solar array.

Costline specializes in servicing and installing solar panels in New South Wales, Queensland, Gold Coast and South Australia. Reach us through our website to learn more about solar PV systems and our high-performance solar solutions.