What you need to know when deciding on a Solar Battery explained

No-one doubts it: electricity is the lifeblood of our daily existence. However, even a brief power outage can feel like an eternity as you try desperately to get your major appliances and systems back up-and-running.

With the ever-increasing cost of electricity and a climate change catastrophe edging closer to us all, investing in a quality solar system complete with solar battery backup is a smart move.

While government incentives like Solar Victoria’s recently announced Solar Battery Loans program tend to make quality batteries more accessible now, there’s no guarantee for the future.

So – let’s help you determine which solar battery size could be right for you and your household, as well as offer some more information about how long your battery will last you under the right conditions.

First things first – the amount of time your solar battery will last will depend on two things:

The size of your solar battery
Your energy usage patterns

Let’s look at battery size first:

How to choose the right-sized solar battery

Whether you already have a solar panel system or plan to install one, adding a solar battery to your current solar system will help you get the most from the solar power your generate.

With various solar battery brands available – including Enphase, Tesla Powerwall, and Sonnen (sonnenBatterie), determining the right-sized solar battery for your system is crucial.

Factors to consider when selecting a solar battery size

Of course, selecting the appropriate solar battery size isn’t a one-size-fits-all decision. Here are the factors we suggest considering:

Your budget: Solar batteries offer long-term savings but involve upfront costs, most of which can be mitigated by the available government solar rebates and incentives available. Consider your budget, including available rebates and incentives, and if in doubt, speak with a solar expert like G Store.
Your energy usage patterns: Analyse your household’s energy consumption patterns. Are there times during the day when you use more/less electricity? What is your average energy consumption each day/week/month? If you have high energy demands, a larger battery may be necessary to help mitigate these.
Your motive for adding a battery: Determine your reason for installing a solar battery. Whether it’s maximising energy consumption, reducing grid reliance, going off-grid, exporting/selling via a Virtual Power Plant program the excess power you generate, or ensuring backup power during blackouts, your motive impacts the battery size.
The size of your current solar system: The size of your solar system (in kW) affects both the energy available for storage, as well as the amount of energy your solar battery can actually store. Put simply, a bigger solar system can support a larger battery – and visa versa.
Your location and environment: Environmental factors, like weather, shading and climate, can influence the efficiency of your solar system and battery storage facility.

Combined, your answers to these questions will help you refine the array of solar battery sizes that are a good fit for you and the needs of your household or business.

How many solar batteries do I need?

Note that most solar batteries are also scalable and modular – meaning they can be linked in order to build additional solar energy storage capacity for you and your solar system.

Most homes of average size typically require 2 to 3 solar batteries, depending on factors like energy usage, motive, and solar system size – plus those listed above.

Additionally, the type of battery you choose matters – for example, lead-acid batteries require more units due to their lower Depth of Discharge (DoD) compared to lithium-ion batteries.

Your solar battery size guide

Here’s a rough size guide for common solar PV systems in Australia:

For a 3kW solar system:

5-10 kWh daily energy consumption: 4 kWh battery for returns, 22 kWh for energy independence
11-15 kWh daily energy consumption: 4 kWh battery
16-20 kWh daily energy consumption: 3 kWh battery

For a 5kW solar system:

5-10 kWh daily energy consumption: 4 kWh battery for returns, 35 kWh for energy independence
11-15 kWh daily energy consumption: 7 kWh battery
16-20 kWh daily energy consumption: 6 kWh battery

For a 10kW solar system:

5-10 kWh daily energy consumption: 4 kWh battery for returns, 35 kWh for energy independence
11-15 kWh daily energy consumption: 8 kWh battery for returns, 65 kWh for energy independence
16-20 kWh daily energy consumption: 11 kWh battery for returns, 90 kWh for energy independence.

Now we understand that the capabilities of your solar battery will largely depend on a) your energy consumption patterns, and b) what size your battery is, let’s talk about the next important topic: how long it will last.

How long will my solar battery last?

During a power outage, an average household in Australia typically consumes 750W to 1000W of electricity – and that’s using only essential appliances.

In such scenarios, a 10kW (10,000W) solar battery can provide approximately 10 to 12 hours of backup power. If your power usage is more sporadic, you might even squeeze an extra hour or two out of it – this will depend, again, on your usage.

However, there is another crucial point to understand. Investing in a 10kW battery is obviously a significant investment, and you’d expect it to last for its maximum guaranteed lifespan in order to get the most from that investment too.

To achieve this, it’s strongly recommended that you adhere to the manufacturer’s guidelines for battery installation and maintenance – something that only a trusted, licensed professional such as G Store can do.

And what about Depth of Discharge (DoD)?

All batteries in the market come with a Depth of Discharge (DoD) percentage recommended by the battery’s manufacturer.

But what is DoD?

DoD indicates the percentage of a solar battery you can use before recharging it. The higher the DoD, the more of the battery’s capacity you can utilise before it will require a recharge. For example, a 10kW solar battery with a 95% DoD allows you to use approximately 9.5kW of power before the battery itself requires recharging.

While it would technically be possible for you to use the entire battery’s capacity in one go, following the manufacturer’s recommendations is essential to ensure the longevity of your battery over its intended lifespan. Note that frequently charging and full discharging can significantly shorten a solar battery’s lifespan – not great if you’re looking for reliable backup!

Brands matter: Enphase, Tesla Powerwall, and Sonnen solar batteries

Now, let’s delve into the overall, high-level benefits of some quality solar batteries available in Melbourne and Victoria, sold and installed by G Store:

The benefits of Tesla Powerwall:

High energy capacity (up to 13.5 kWh)
Scalability to meet increasing energy demands
Durability in extreme weather conditions
Advanced lithium-ion battery technology
Intelligent software for energy optimisation
Aesthetic design
Proven track record
Participation in Virtual Power Plant (VPP) programs

Enphase solar battery benefits:

Higher efficiency
Modularity and scalability
Advanced monitoring and control
Longer lifespan
Enhanced safety features
The Enphase IQ Battery 5 offers a 15-year warranty and exceptional power delivery

Benefits of the Sonnen solar battery (sonnenBatterie):

Exceptional energy efficiency
Robust and weather-resistant design
Intelligent energy management
Scalability for various energy needs
Safety and sustainability with non-toxic materials
Overcharge and over-discharge protection

Confused about which solar battery is right for you? Just give our friendly, award-winning G Store solar team a call on 1300 766 940 and we’ll help you out.

Wrapping up

Ready for some tailored advice?

To learn more about our full range of trusted, quality solar battery storage systems, visit our Learning Centre or give our team a call today on 1300 766 940.

We can’t wait to chat with you.

How Long Does a Solar Battery Last?