Lithium Ion Batteries and Solar Battery Storage

Tesla Powerwall 2

a Tesla Powerwall 2 Lithium ion battery

Lithium-ion batteries are a newer form of battery storage technology that are are rapidly displacing lead-acid batteries for solar storage in grid-connect scenarios.

This is mainly due to the fact that lithium-ion batteries can be discharged deeper and have a longer lifetime than lead-acid batteries. They will give you around 4,000 – 6,000 cycles at 80% discharge. So, assuming good quality they are expected to have a usable lifespan of 13-18 years at this discharge level; although providing decreasing capacity as the years go by. And note that home battery warranties are usually only around 10 years. 

Their main drawback, at least at the moment, is that they are about 50% more expensive than lead-acid batteries for the same amount of storage. This was expected to change rapidly as mass-production of lithium-ion batteries significantly reduced the cost of lithium-ion storage. But it really hasn’t happened yet.

How much will a lithium ion + solar setup cost?

This all depends on the brand of battery you choose to go with. As I have outlined in another article, there are a number of competitors in the lithium-ion battery storage space, with a great deal of variance in pricing-per-kWh.

Everyone seems to be hyped about the Tesla Powerwall, though – so I will use it in this example. A Tesla Powerwall and gateway costs around $12,100 as of February 2024. That doesn’t include installation.

As a very rough guide, a 6.6kW solar power system costs around the $6,300 mark. If you add the Powerwall 2 price to this, and add the Powerwall installation cost, you wind up with a total cost of around $21,500.  And it could be higher depending on the complexity of the battery installation.

I’ll be the first to admit that $21,500 is a lot of money for the average Australian to find, even if they’re extremely keen on adding battery storage to their solar PV system. My recommendation is to go solar now, but wait for battery prices to drop before considering adding a Powerwall if the focus on getting a battery is to save money and those numbers don’t work out for you.

However, Tesla Powerwall isn’t the only game in town and there are home batteries that cost less – but it’s still very important to crunch the numbers. You can check out prices and other specification on our solar battery comparison page.

About Finn Peacock

I’m a Chartered Electrical Engineer, solar and energy efficiency nut, electric car and e-bike owner, dad, and founder of My last “real job” was working for the CSIRO in their renewable energy division. Since 2009 more than 750,000 Australians have used my site to get quotes for high quality PV systems from pre-vetted solar installers.

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