We’re reader-supported and may be paid when you visit links to partner sites. We don’t compare all products in the market, but we’re working on it!
Batteries have been around for centuries, but only recently have residents started incorporating deep-cycle batteries into their home solar array. Prices on solar batteries have been dropping for a while as the technology develops, but even now, these ultra-efficient batteries are pretty pricey.
So are home solar batteries worth it? Likely no but possibly yes, depending on what you're after.
Can home batteries actually save you money?
|Home battery||Cycles||kWh per cycle||Total kWh produced||Total cost (AUD)||$ per kWh used|
|AGL Power Advantage||5,000||3||15,000||TBA||TBA|
|Aquion Energy S20P||3,000||2||5,430||$1,642.14||$0.30|
|Iron Edison 24V Lithium Battery||2,000||2.76||5,530||$3,925.50||$0.71|
Should I get a home battery?
For the majority of home customers, the answer is probably no. While the price of batteries has decreased over time, a battery and inverter will still set you back $8,000 to $15,000. This is the kind of investment that is unlikely to be recouped over the effective lifetime of the battery.
However, if you are planning to invest in a home battery for storage or potentially backup, you should ensure that you get a strong warranty on it to protect your investment. You may be able to take advantage of government rebates or renewable schemes in your state or territory, especially VIC, SA, the ACT and QLD.
Just keep in mind that if you're funnelling power into your storage battery you aren't feeding it back into the power grid, meaning that you won't be able to benefit from solar feed-in tariffs for that energy.
- Can work as a backup. Depending on your battery and set-up, you may be able to disconnect your house from the grid in the event of a blackout and rely upon stored energy from your battery to power your appliances.
- Save power for later. With a battery, you can take advantage of almost all the solar energy you produce. Alternatively, you could change to a time of use tariff on your power plan and use your stored energy during peak hours.
- May be able to take advantage of tariff rates. Some retailers pay higher feed-in tariffs for battery users with stored energy when the power grid is experiencing a shortage.
- Price. While there has been a drop in prices of home batteries over time, don't expect one to come cheap even now. The price of a 7kWh Powerwall is around $3,800 and the 10kWh model sells for around $4,435.
- Tariff loss. A unit of energy spent charging your battery is usually a unit of energy you don't feed back into the grid. You may end up losing out on some solar feed-in tariffs, especially on low-efficiency batteries.
How to compare home batteries
- Capacity/power. Capacity is how much electricity a battery can store, while power is how much energy a battery can provide at a specific point in time. High capacity alone doesn't mean your battery will last a long time, since a higher power output could mean it lasts for a shorter duration but can power many devices at once.
- Depth of discharge (DoD). Dropping some batteries below a percentage of their maximum charge – their DoD – will damage their ability to function. A higher DoD means you can tap into more stored energy safely.
- Round trip efficiency. This is the percentage of useful energy you get out of a battery as a fraction of how much you put in to charge it. For example, if you get 9kWh out of a battery charged with 10kWh of power, it has a 90% round trip efficiency. A higher efficiency means you get more out of your battery with each charge.
- Battery life and warranty. Batteries become less and less efficient over time. Your battery will be rated for a certain number of cycles of charging and discharging. Warranty on your battery will often guarantee a certain capacity after a period of use, such as 80% of its max charge after 3,000 cycles.
Which battery type is best?
There are three types of batteries that can be used for solar installations: lead-acid, lithium ion and saltwater. Of the three, lithium ion currently performs best, though the others may be considered for cost purposes.
- Lithium ion. This is the most common battery type, consisting of a mix of lithium and other metals to form a cell. They have a high depth of discharge and a long expected lifespan of thousands of cycles. The main drawback is their price and the fact that they can be difficult to recycle.
- Lead-acid. This is a tried and tested battery technology that's been in use for ages in cars and other heavy devices. Unfortunately, they don't offer nearly as long a lifespan or high efficiency as lithium ion cells. They are far cheaper, but are slow to charge.
- Saltwater. These contain no toxic chemicals and are totally safe, containing saltwater as their only ingredient. While they're fairly efficient and can last a long time, they have a really low power output and are extraordinarily bulky. On top of that, they're not particularly environmentally friendly, either. Saltwater batteries are currently only made by one company, Aquion Energy.
Solar Run is a solar retailer who can help you install solar on your rooftop.
- Get quotes for solar panels and battery storage
- Clean Energy Council approved retailer
- NSW, VIC, SA, QLD and ACT
Note: Solar service is not available in the Northern Territory, Tasmania and Western Australia.
More guides on Finder
Electric car ownership guide
Find out how to switch from a fossil-fuel guzzler to an electric car.
2020 Hyundai IONIQ Electric review
If you want a thoroughly practical electric car, the Hyundai IONIQ Electric is one of the most affordable and usable battery-powered models.
Energy bills have doubled during the coronavirus pandemic
Australian residents have seen their energy use jump during the pandemic. Find out how bills have changed and how you can deal with them.
Tesla Model S Review
Compare expert reviews of the Tesla Model S
Hyundai Kona Electric Review
The Hyundai Kona Electric is a viable bridge between high-end SUVs and lower-cost vehicles, that also happens to be a battery-powered car.
Tesla Model 3 Review
Tesla Model 3 comparison reviews
Australia reaches “50%” in renewable energy use for the first time ever. But what does this mean?
For 10 minutes, 50% of Australia's main electricity grid was powered by renewable energy, indicating an upward trend in green energy use.
GreenPower vs carbon neutral vs green ratings – green energy options explained
Green energy options can be confusing, so we've compared GreenPower, carbon neutral energy and green energy ratings to help you find the right green option.
Energy discounts in Australia
Discounts or benefits aren't 100% straightforward. This guide explains what you need to know.
Lower your household bills
Compare internet from over 50 providers in our broadband engine.
Check out our select picks of the best plans available.
Mobile broadband is fast becoming a viable alternative to fixed line.
Ask an Expert