How Does Solar Battery Storage Work?
The popularity of solar power has led to the rise of another renewable technology: solar batteries that can store extra solar power for later use. Companies like Tesla are developing batteries that can be installed with solar panels to create “solar-plus-storage” systems for your home.
A solar battery is a battery that stores energy from a solar PV system. The system’s panels absorb energy from the sun and convert it to electricity which then passes through the inverter for your home to use. A battery is an additional component that can allow you to store energy produced from your solar panels and use the energy at a later time, such as in the evening when your panels are no longer producing energy.
Solar batteries for home explained
To appreciate why you might choose to install a solar-plus-storage system for your home, you first need to understand how a standard home solar PV system functions.
The typical solar energy system includes solar panels, an inverter, equipment to mount the panels on your roof, and a performance monitoring system that tracks electricity production. The solar panels collect energy from the sun and turn it into electricity, which is passed through the inverter and converted into a form that you can use to power your home.
The vast majority of residential solar energy systems are connected to the electricity grid (or “grid-tied”). When your panels are producing more electricity than your home needs, the excess is fed back into the power grid. Conversely, when your home needs more electricity than your solar panels are producing, you can draw power from the electric grid.
In most cases, you receive a credit on your utility bill for the electricity you send back to the grid. Later, when you are using more electricity than your solar panels have generated, you can use those credits instead of having to pay more to your utility. This process is known as net metering.
How Does Solar Battery Storage Work?
As mentioned previously, excess energy from your solar PV system is deposited into the battery. This means that the energy surplus can be stored in it and is readily onsite for you to draw from when your solar panels aren’t generating enough electricity.
When choosing the type of battery to use for energy storage, consider the following:
- Battery life and warranty
- Power capacity
- Depth of discharge (DoD)
A battery’s lifespan is generally somewhere from five to 15 years, although it is expected to increase significantly to keep up with the growth of solar panels through the years. Warranties for batteries are generally stated in years or cycles, for example, Victron energy has a warranty of 2 years.
The power capacity refers to the total amount of electricity that the battery can keep. Solar batteries are usually stackable, meaning you can have multiple battery storages at home to increase capacity.
The DoD measures the degree to which a battery can be used relative to its total capacity. If a battery has a 100% DoD it means you can use the full battery storage amount (e.g. 2.5kWh) to power your home. If a battery has a 94% DoD, it means you can use up to 94% of the battery capacity (e.g. for a 2.5kWh battery, you can use down to 2.35kWh before the battery needs to charge again).
Common Solar Battery Types
- Lithium Ion
For the most reliable lifespan and DoD, your best choice for your home battery would be Lithium-ion. The majority of new home battery storage uses this technology, as they have a longer lifespan and higher DoD. Lithium-ion batteries are also more compact, although they’re more expensive compared to lead-acid batteries. Examples of lithium-ion batteries include the sonnenBatterie, LG Chem Resu, and Tesla Powerwall.
- Lead-acid
Lead acid batteries have been used for decades and are one of the cheapest varieties in home energy storage for off-grid power systems. The downfall to buying this type of technology is that it is becoming outdated and has a lower DoD compared to other battery types.
Conclusion
It’s that simple! Solar batteries capture excess solar power and allow for that power to be used when it’s most beneficial for the homeowner, like during an outage or to take advantage of additional electric bill savings. Speak with one of our Energy Advisors to see your customized solar and battery system!
