Choose the best solar battery system for your home
Considerations in choosing a battery
If a home solar battery system is right for your household, these are items to keep in mind when selecting which system to buy.
Battery capacity
The battery capacity is the amount of energy the battery can store. This will determine how long the battery can power your home at night or during a power outage. If you are interested in backup power, you may require a larger capacity.
Peak power output
A battery’s power rating is important for determining how many appliances you can run at the same time. The peak power output is the maximum amount of power that a battery can provide to the household over a very short period.
The maximum continuous power output is the amount of power the battery can output for a sustained period.
It is important to understand whether you need to power large appliances or rely on the battery during a power outage. Talk to your retailer to see what suits your circumstances best.
Warranty
Battery energy storage system warranties can range from 5 to 15 years or more. Consider the warranty together with the expected lifespan of the battery.
Making a claim under warranty may be easier and faster with a local battery manufacturer. Talk to your retailer to find out more.
Charge and discharge cycles
The charge/discharge cycle is about how many times a battery can be charged and discharged before it loses capacity. Battery energy storage systems typically have a lifespan between 4,000 to 6,000 cycles (about 1 cycle per day for 10 to 16 years).
Depth of discharge
The depth of discharge refers to the amount of a battery’s capacity that can be used before recharging. Discharging a battery until it is completely empty is possible, but it can damage the battery and reduce its lifespan.
Efficiency
Battery efficiency determines how much energy is lost during charging and discharging. Higher efficiency batteries waste less energy and perform better over time. For lithium-ion batteries, it is advisable to look for options with efficiency ratings of 90% or above.
Smart features and remote monitoring
Some battery systems have smart features like remote monitoring, home energy management systems, and smartphone apps. These features provide real-time insights into your energy usage and battery performance.
Choosing the right battery size
The right battery size for your home will depend on:
- the size of your solar photovoltaic (PV) system
- your average daily electricity consumption
- energy usage patterns
- whether you’d like backup during a power outage
- budget and other financial considerations
- any changes you might want to make to your energy system in the future, for example, switching from a gas water heater to an electric heat pump.
If you do not already have a rooftop solar PV system for your home, it’s best to discuss options with an accredited solar retailer to help understand what size of solar PV system would suit your household's needs. This will help you decide what you will need to consider when buying a battery.
How you will use your battery
Will you need overnight power from your battery? What about having battery power during a power outage? Answering these questions will help you work out what size and other system features best suit your household's needs.
Power through the night
Size your solar system and battery so that the battery can be fully charged by solar power during the day, and discharged to cover your electricity needs overnight.
To calculate your excess solar energy and your overnight energy use, a starting formula is:
Total average daily energy use – average daily solar energy use = excess solar energy
Backup power for outages
Not all home battery energy storage systems can provide backup during power outages. If you experience power outages often, or your household contains critical electrical equipment, discuss with your system designer what you might need.
If having backup during a power outage is important to you, you may want to consider a battery that is big enough to cover several days of energy use. You may also want to consider an on-site diesel generator for additional backup.
For more information about electrical safety during storms, visit the Electrical Safety web page.