Guide on How to Buy the Best Solar Battery Storage

buying solar battery storage

If you’re thinking about adding a battery energy storage system (BESS) to your solar setting, you came to the right place.

In this Guide for buying the best solar battery storage, we went through all the benefits, customer concerns and factors that can affect the product quality.

Home solar batteries and how they work

How do home solar batteries work?

Solar batteries should provide you with a 24/7 power supply. When there’s no adequate solar or wind power, your home can still be powered with green energy thanks to the battery storage technology.

This is a more advanced technology than the batteries you use for your remote control, for example, because they use algorithms that coordinate energy production and direct it to reserve it or release it to the grid. The stored energy can later be used in times of peak demand, which helps in keeping your electricity costs low.

In other words, these devices can store the solar or wind energy you generate, which you can later use when you need additional power.

How many are currently installed in Australia?

By the end of 2020, there were 16 large scale batteries under construction, with a total capacity of over 595 MW. Several more have been announced to be built in 2021.

As for household battery storage systems, in 2020 there were a total of 23,796 batteries with a capacity of 238 MW. This is a significant increase compared to 2019 when there were around 22,621 combined batteries.

South Australia reportedly has the highest number of domestic batteries, exceeding 7,150.

However, Federal Labor announced a target of 1 million households with batteries by the year 2025.

Types of solar batteries 

The most common types of batteries used for storage systems are lithium-ion or lead-acid. There are more options, such as flow batteries, which are on the pricier side, or nickel-cadmium and nickel-metal hydride. These three are less common, so you should check with your installer or system designer if those options are more suitable for your needs.

TypeDescriptionAdvantages
Lithium-ionUsually used for mobile phones, laptops and electric cars, they’ve proven to be ideal for supplying large scale plants with renewable energy.-High capacity and storage-Lightweight, higher voltage-Longer life cycle
Lead-acidWith technology similar to car batteries, they are mostly used for rural homes where the grid connection is more expensive.-More affordable-Easy to acquire-98% recyclable

Benefits of Installing Batteries

Deciding to install solar now goes hand in hand with installing batteries because of their many benefits, with some of them being:

  • Reducing your reliance on grid-tied electrical system.
  • Taking full advantage of your solar panels by storing the energy and saving it for when you later need it.
  • You’d have electricity even during power outages.
  • You’d be independent of future electricity prices rising.

What to look for when buying a home solar battery

First things first, you’ll want to look for storage products qualified for the Clean Energy Council Battery Assurance Program, which means they meet the standards customers are expecting from household appliances.

Your designer or retailer should advise you on the appropriate system for your solar setting, according to your needs, the size of the solar panels, tariff and energy use. That’s why it’s recommended to stick with Approved Solar Retailers who have signed the Solar Retailer Code of Conduct and only use designers and installers accredited by the Clean Energy Council.

You should address the following factors when discussing battery storage options with your system designer:

  • Battery Capacity – The charge amount it can deliver, expressed in kWh.
  • Daily Energy Use Requirement – Usually battery storages for a typical household vary from 3-12 kWh in size.
  • Safety – For Australian conditions, it’s recommended to locate the battery on the south/east-faced side of the house, in a ventilated space with a stable temperature.
  • Maintenance – The system should be serviced once a year by an accredited installer, who may ask you to keep monthly checks of the system measurements.
  • Lifespan – Depends on the quality of usage, ambient temperatures and your electricity consumption changes.
  • Energy Cycles – For lithium-ion batteries it ranges from 4,000-6,000 cycles at an 80% discharge rate, meaning the systems should last 10+ years.
  • Battery Recycling – Depends on the battery type, for example, a lead-acid battery is 98% recyclable.
  • Storage Size – The typical house battery storage comes in a size of a small fridge, whereas, for commercial purposes, it can be up to a 20-foot shipping container.
  • Solar Battery Cost – The full system instalment costs around $1,000-$2,000 per kWh, so it depends whether you’re using a 5 kWh system or a 10 kWh one.
  • Warranty – Usually lasts around 2-10 years, but most retailers will offer you an additional warranty which includes workmanship, installation, performance and system operation.

Note: Keep in mind this cost estimation is for lithium-ion batteries, which are more expensive than lead-acid ones, as well as the fact that the prices of battery storage are falling over time. Moreover, once installed, running a battery system will have minimal costs.

The Most Common Ways to Purchase a System

When deciding to purchase a house battery storage system, you will be offered the following options:

SystemDescriptionAdvantagesDisadvantages
Off-the-shelfAll in one, with little customisation.-One manufacturer-One warranty-Predefined energy and power limits
Semi-customisedThe designer selects components (e.g. inverter) and connects them to an off-the-shelf battery.-Customizable-Flexible energy and power limits-More than one manufacturer and warranty-More complex
Fully-customisedThe designer makes it from individual cells or modules and connects it to the battery storage.-Most customizable energy and power limits-Multiple warranty considerations-The most complex

 Things to consider before buying

House Battery Storage System Basics

When speaking about storage systems, there are two key points:

  • Power – How fast the energy can be supplied (kW)
  • Energy – How much energy your system is storing (kWh)

An average household uses about 18 kWh of energy on a daily basis, while the power consumption is around 4.5-15 kW.

In this sense, storage systems usually have a 2-5 kW power rating, with a 2-10 kWh energy rating. So for example, for a clothes dryer to run for two hours, you’re gonna need battery storage with a minimum of 2.4 kW and 4.8 kWh energy rating.

The installation process doesn’t last longer than 1-2 days for typical house settings.

Consider the feed-in tariff (FiT)

In Australia, the FiT differs from state to state. In some cases, the state has agreed on a minimal rate, whereas in others retailers are deciding on it, so you may want to get informed about which retailer offers the best deal.

You should go with the one that minimises your total energy cost and you can also get advice from the relevant state government departments.

Grid-connected vs Off-grid battery storage

If you’re connected to a grid-tied electrical system, your provider can supply you with additional amounts of solar or wind energy, balancing the supply and demand. This way of power supply is reliable and convenient.

However, if your area does not have access to the electricity grid, or if you prefer not to use it, then storing the energy via batteries is just as good. They can be connected with freestanding solar panels, small wind turbines or even diesel generators.

Also, keep in mind that going completely off the grid can be impractical if you’re unable to store enough energy to use during the night or cloudy days, especially in the winter. Moreover, you won’t be able to sell back to the grid any excess energy.

You can also choose the combination of staying connected to the grid and relying on your own solar and battery system.

What are the main ways your home can be set up for electricity supply?

Your household storage battery system can be connected in two main ways:

Direct Current (DC) – It’s usually using a single inverter to convert the DC electricity to AC and provide energy to your house, or to feed the grid back. This is how it looks:

Alternating Current (AC) – While DC is integrated into your solar system, AC is separate. It’s using AC electricity to charge batteries and discharge them to your household wiring through its own inverter.

What happens in a blackout?

Not every storage battery will work during a blackout, but some are designed to be operative even then. If this is an important factor to you, make sure to check in advance with your installer which storage products to pick.

You will probably be recommended with an uninterruptible storage system (UPS), which is a bit larger, more complex and pricer, but will provide you, as the name says, with an uninterrupted supply of electricity.

However, if during a blackout your battery is charged, you will be able to run important appliances, such as the fridge. Some storage systems even have a power point to which you can plug your devices in case of a blackout.

Conclusion

Storage battery gives you great control of how you use and distribute the power, as well as helps you take full advantage of the solar energy you already generate.

We hope this guide helped you in your research and that it answered most, if not all, of your question regarding battery storage.

FAQs

1. Is solar battery storage worth it?

It is worth it because it can provide you with more efficient use of the energy you already generate through your solar panels.

2. How long does solar battery storage last?

With proper maintenance, it usually lasts around 10 years.

3. What size solar battery do I need?

It depends on the size of your household and your habits, with the two most common systems being 5 kWh or 10 kWh. In this Guide for buying the best solar battery storage, we explained it in detail.

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