How Do Solar Batteries Work?

A solar battery stores energy from a solar PV system. A battery is an extra added component that allows you to store the energy produced from your solar panels and use it later when you need it. The panels are responsible for absorbing the energy from the sun and converting it into electricity that passes through the inverter for your use.

Generally, the solar PV system is connected to an electricity grid. This provides your home with electricity even if your panels are not producing enough energy to meet your demands. In cases when the electricity generation is higher than your consumption, the excess energy is sent back to the grid.

If you have an off-grid system or would choose to store the excess energy yourself instead of sending it back to the electricity grid, solar batteries are a great addition to your solar PV system.

How does Solar Battery Storage Work?

The popularity of solar power has given rise to another technology i.e, solar batteries. These batteries can store extra power for later use. The excess energy from your solar PV system is directly deposited into the battery. This means the energy surplus can be stored onsite for you to use when your solar panels are not generating enough electricity.

Any typical solar energy system is made up of solar panels, certain equipment that allows you to mount the panels on your roof, an inverter, and a performance monitoring system that can track electricity production. The panels absorb energy from the sunlight and turn it into electricity which is later passed through the inverter for you to power your house.

How do you Charge Solar Batteries?

Solar panels alone do not charge your batteries, but the overall process isn’t complicated all at. All you need is a charge controller, an inverter, and a battery. The total charging time depends on the battery capacity. For example, a 12-volt battery can take anywhere between 5 to 8 hours to charge fully.

Charge Controller

This component entirely depends on the total size of your solar system. Any unit that contains a maximum power point tracking (MPPT) circuit can maximize the transferred energy. Along with that, it can automatically disconnect the solar panel from the battery once it is fully charged.


The size and type of battery you choose depend on your energy requirement. A 12-volt, deep cycle battery can handle repeated charge/recharge cycles without damaging the internal plates or electrolytes. The average automotive battery is designed such that it is not repeatedly drained and also replenishes without failing quickly.


An inverter is a vital component that can transform the electricity stored in the battery to power your home. It is inexpensive but you must make sure to check the total number of electrical sockets it can power.

Things to Consider While Buying Solar Batteries

If you are looking forward to buying solar batteries, you must consider the following criteria:

Battery Life and Warranty

The total lifespan of a battery is somewhere between 5 to 15 years. With the massive growth of solar panels, even the battery life is expected to increase significantly through the years. Warranty for any battery is generally stated in years or cycles.

Round-trip Efficiency

The round-trip efficiency of a battery represents the amount of energy that is suitable to be used as a percentage of the total energy the battery has in store. A higher round-trip efficiency ensures more economic value of your battery.

Power Capacity

The power capacity of a battery is the total amount of electricity it can store. Usually, solar batteries are stackable and thus allows you to store multiple batteries at home to increase capacity.

Depth of discharge (DoD)

The DoD can measure the percentage of energy that can be used compared to its total capacity. A battery with a 100% DoD lets you use the full battery storage amount to power your home. However, a battery with a 94% DoD, lets you use up to 94% of the total battery capacity.

Solar Battery Types

1. Lead-acid

Lead-acid batteries have been around for decades. These are one of the cheapest alternatives for home energy storage with off-grid power systems. The downfall of this technology is that it is outdated and gives a lower DoD compared to other batteries

2. Lithium-ion

For a reliable lifespan and DoD, you can choose Lithium-ion batteries for your home. Nowadays, the majority of home battery storage uses this technology as it ensures a longer lifespan and higher DoD. Lithium-ion batteries are expensive and very compact compared to lead-acid batteries.

3. Saltwater

The saltwater battery is a newcomer in the home energy storage industry. Unlike other storage options, these batteries do not contain any heavy metals. These types of batteries rely on saltwater electrolytes and can be recycled easily. But this new technology is relatively untested.

Benefits of Solar Batteries

  • Energy Independent

Batteries can help to maximize your solar self-consumption by reducing the amount of electricity you consume and purchase from the grid. These batteries also power your home in the evening by storing the excess energy produced during the day. It is always available for use whenever you need it.

  • Balanced Short-term Power Fluctuations

These solar batteries can help in managing high demands and acts as a backup for power outages. Installing renewable energy storage solutions can directly impact the supply and demand for renewable energy.  It can give you more flexibility in producing and using electricity.

In practical terms, solar batteries offer a short-term backup power in case there is a power outage in your area. It allows you to have high control over your electricity use.