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Solar battery backup systems: Are they worth the cost?

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Sometimes in a blackout, candles just don’t cut it. If you’ve got solar panels, then you may have considered installing a solar battery with backup capabilities. But is it truly worth the extra cost? Canstar Blue investigates.

Solar batteries have been a hot topic for the energy community for a while now, particularly as more Aussies choose to install home solar systems. But perhaps one of the most widely debated discussions for solar batteries is the cost.

It is no secret that they are expensive. Even with a Virtual Power Plant (VPP) or a solar rebate, solar batteries still have a significant upfront cost, and this price grows as features are added, such as backup capabilities. These features, however, do have a pretty important role to play when it comes to powering your home off-grid, particularly in the case of a blackout.

It can be tricky to determine whether you’ll really need backup capabilities in your solar battery system, especially given the alienatingly-high price tag, but that’s where this guide comes in handy. In it, we’ll discuss how these systems work, how it may differ from any other old solar battery on the market and of course, whether it is worth the investment.

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What is a solar battery backup system

A solar battery backup system is essentially a solar battery that has the ability to continue to power essential appliances during a blackout. A good system will also be able to continue collecting energy from the solar panels so that the battery is not instantly depleted.

There are different levels of backup battery. To determine which you would need, it might be worth considering how often your neighbourhood suffers from blackouts, how long they last for and which critical appliances you’d need to continue running. If blackouts are not very common where you live, you’d probably be okay with a regular battery.

While a solar battery backup system would not necessarily mean that you could “live off the grid” forever, it could help to power your essential appliances (including lights) during a blackout.

How does solar battery backup work? one house with lights on

When a blackout occurs, solar batteries with backup capabilities kick in, as long as there is enough energy stored before the power goes out.

The set-up is fairly simple: a cable is run from the battery and solar inverter to a selected number of circuits in the switchboard, protected by a main battery circuit breaker and one changeover switch for protection. Essentially, this divides your home into two circuits, “essential” and “non-essential.” Things like your fridge, oven and lights may be put in the essential category while your non-essentials such as the coffee machine or gaming system might not make the cut.

In the event that the power does drop out, these appliances would then draw on electricity directly from the battery, meaning that even during a blackout your solar power can keep the lights on.

How does a battery with backup differ from a regular solar battery?

The main difference between a regular solar battery and those with backup capabilities is that regular batteries can’t be used during a blackout. It can, however, still be used at night or on cloudy days when your solar panels aren’t generating enough energy for your household. Generally, solar panels are switched off during blackouts to prevent the system from overloading.

A solar battery with backup capabilities can both provide power at night and during a blackout as well as, depending on the model, allowing the solar panels to continue to generate power – for both the house and to recharge the battery.

What is the lifespan of a solar battery backup system?

The lifespan of a solar battery backup system is typically 10 to 15 years. Most solar panels however, have a lifespan of 20 to 30 years, which means you may have to replace the battery system during this time.

How much is a solar battery backup?

Not all battery systems offer backup capabilities because it is more expensive and labour-inducing to install. A regular solar battery storage system without backup can cost between $1,000 and $2,000 per kilowatt hours (kWh) of storage capacity. If you’re interested in getting backup capabilities, expect to pay an additional $1,500 to $3,500.

Compare Solar Plans & Prices

Here are some of the cheapest solar-specific deals from the retailers on our database. These costs are based on the Ausgrid network in Sydney but prices will vary depending on your circumstances. We show one product per retailer, listed in order of lowest price first. Annual price estimates assume general energy usage of 3911kWh/year for a residential customer on a single rate tariff. Price estimates exclude solar feed-in tariff credits. These are products from referral partners†. Our database may not cover all deals in your area, and please check retailer websites for up to date information.

Here are some of the cheapest solar-specific deals from the retailers on our database. These costs are based on the Citipower network in Melbourne but prices will vary depending on your circumstances. We show one product per retailer, listed in order of lowest price first. Annual price estimates assume general energy usage of 4000kWh/year for a residential customer on a single rate tariff. Price estimates exclude solar feed-in tariff credits. These are products from referral partners†. Our database may not cover all deals in your area, and please check retailer websites for up to date information.

Here are some of the cheapest solar-specific deals from the retailers on our database. These costs are based on the Energex network in Brisbane but prices will vary depending on your circumstances. We show one product per retailer, listed in order of lowest price first. Annual price estimates assume general energy usage of 4613kWh/year for a residential customer on a single rate tariff. Price estimates exclude solar feed-in tariff credits. These are products from referral partners†. Our database may not cover all deals in your area, and please check retailer websites for up to date information.

Here are some of the cheapest solar-specific deals from the retailers on our database. These costs are based on SA Power network in Adelaide but prices will vary depending on your circumstances. We show one product per retailer, listed in order of lowest price first. Annual price estimates assume general energy usage of 4011kWh/year for a residential customer on a single rate tariff. Price estimates exclude solar feed-in tariff credits. These are products from referral partners†. Our database may not cover all deals in your area, and please check retailer websites for up to date information.

Is solar battery backup worth it?

The main reason homeowners get solar batteries with backup capabilities is for peace of mind and knowing that even if the power does go out, their essential appliances will still be able to operate. But realistically, whether it’ll be worth the investment for your house or not will depend on your home’s energy usage and goals.

Solar batteries are a huge investment and the payback isn’t always ideal. Unless you’ve got a really good model, then you might even find it is not that useful during a power outage. They also tend to have a slightly smaller lifespan than solar panels, meaning you would most likely need to have it replaced at least once in your solar panel’s lifespan.

That being said, they can be a great addition to a home solar system. With the added benefit of accessing your solar energy at all times of day, no matter the circumstance, you can rest assured that you have at least enabled your system to operate at its best in all conditions.

If you are on the hunt for the right solar battery system for your home, then be sure to check out some of the top contenders currently available in Australia below. These models have been broken into best for price, size, backup capabilities and more.

See the best home solar battery storage

Image credits: New Africa/Shutterstock.com, Jochen Kost/Shutterstock.com

Kelseigh Wrigley
Energy Specialist
Kelseigh Wrigley was a content producer at Canstar Blue for three years until 2024, most recently as an Energy Specialist. She holds a Bachelor of Journalism from the Queensland University of Technology.

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