With the rising cost of grid electricity and the well-improved technology behind solar power, adding a solar battery to your system has become more practical than ever. Although, with so many choices, finding the best solar batteries for your home is also a challenge.
While the choice is ultimately yours, we prepared a buyer’s guide to point you in the right direction. It includes factors and features that you should be looking for in every battery as well as our top 5 recommendations.
If you have little to no knowledge about solar batteries, I recommend reading this from the top. But, if you want to skip sections, you can do so with a tap on the bullets below:
- Battery size and depth of discharge (DoD)
- Battery life, cycle life, and warranty
- Round-trip efficiency
- Power ratings
- Battery types
- Value for money
- Our top 5 solar batteries
Factors to consider when choosing a solar battery for your home
Battery size and depth of discharge (DoD)
These 2 things are different but also interrelated. The size of your battery is the total amount of energy it can store while its DoD is the depth at which it’s safe to discharge. Battery size is measured in kilowatt-hours (kWh) whereas the typical DoD of solar batteries is 80-95%.
Let’s say for example you have a 10 kWh battery with a DoD of 80%. This means that you will only be able to use 8 kWh from your battery’s capacity if you want it to last as long as its projected lifespan. So, the higher the DoD, the better.
You will encounter either of 2 problems here:
- Undersized battery systems. This is when your battery size and DoD are too small to make any relevant change to your reliance on the grid (and therefore your power bills).
- Oversized battery systems. This happens when you have a battery that’s larger than your solar system is capable of charging.
In my opinion, an oversized battery system is a better problem to have. After all, it opens up the possibility of installing more solar panels in the future. The catch is that you’re paying for storage that you’re not using at the moment.
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Battery life, cycle life, and warranty
Battery life is how long your battery lasts. Cycle life is how many charge and discharge cycles it has before it becomes unusable. Warranty is the manufacturer’s guarantee concerning how long your battery system should last.
Your battery’s lifespan is dependent on its cycle life. The more cycles your battery is rated for, the longer it lasts. On average, though, modern solar batteries in Australia can last anywhere between 8-15+ years. Some even last up to 20.
On the other hand, warranties are different from manufacturer to manufacturer but they last 10 years on average. Also, your battery is considered “dead” if its lost 30% of its total capacity.
Round-trip efficiency
The round-trip efficiency of a solar battery goes hand in hand with the previous factors. It’s how efficient your battery is at storing the solar energy that’s sent to it.
For example, let’s say your solar battery has a round-trip efficiency of 60% and your solar panels are sending 10 kWh of power to it. Your battery will only be able to store 6 kWh. The rest of the 4 kWh is lost.
Granted, 60% efficiency is low. I recommend going for batteries that have a round-trip efficiency of at least 80%.
Power ratings (continuous power rating & peak power)
There are 2 kinds of power ratings you need to be concerned about when choosing a solar battery for your home:
- Continuous power: The amount of electricity your solar battery can constantly put out. This is important for appliances that need constant power, like your fridge.
- Peak power: The maximum amount of electricity your solar battery can put out at one time. These are for appliances that you will be turning on and off, like lights, power tools, and heaters.
Both of these ratings are measured in kilowatts (kW). They’re both important because they tell you how many appliances you can run at the same time, as well as which ones.
In general, you will want to look for a solar battery with a continuous power rating of 5 kW and a peak power of 7 kW. If you have more appliances than the average Australian home, look for higher values.
Different types of solar batteries
You should also consider the type of solar battery you’re getting as each of them has its pros and cons.
1. Lithium batteries
There are different kinds of lithium batteries available. The most commonly used in Australian homes right now are lithium-ion batteries (Li-ion). They’re small, affordable, and use liquid electrolytes.
However, lithium iron batteries (a.k.a. LiFePo4 or LFP ) are quickly taking the reigns as they are safer, are more efficient in warmer climates, and are still affordable. They’re heavier and take up more space, though.
2. Lead acid batteries
Lead acid batteries are an older battery system compared to lithium batteries. They’re also larger and have a lower DoD. Hence, why it’s become an uncommon choice in Australian households.
The only reason I would recommend lead acid batteries today is if you were on a very tight budget, had a lot of extra space, and don’t require a lot of energy.
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3. Saltwater batteries
The best things about saltwater batteries are that they don’t require any maintenance, they’re the most environmentally-friendly option, and they last about twice as long as lithium batteries.
The main difference between this solar battery and the others is that this uses saltwater (i.e. sodium) to store and conduct electricity. It’s also because of this that it doesn’t run the risk of catching fire.
Unfortunately, it also stores less energy and has a lower peak power rating. So, it won’t be able to power as many appliances. It’s more expensive, too.
4. Solar gel batteries
First, gel batteries are made to provide a steady and constant stream of electricity.
Being made with gel instead of liquid also means that you don’t have to worry about leaks. They can be installed in a variety of positions, too. This makes solar gel batteries altogether reliable and versatile.
The catch is that they have a shorter cycle life than lithium-ion batteries, lower round-trip efficiency and take longer to charge. Plus, a lot of them are more expensive than lithium-ion batteries.
Value for money
I see value for money as what you’re getting for the cost of the battery – and it all depends on what you need it for.
On that note, installing a battery alongside a new solar system is going to cost you roughly 1000 AUD per kWh. However, adding one to your existing solar system is going to add around 2000 AUD more to your total bill.
That being said, most Australian homes use lithium-ion batteries because they’re affordable for the efficiency, durability, and amount of power that they’re capable of storing.
But, as I said, other batteries have their pros and cons. Not to mention the many different brands and models. So, weigh your options and get the best one that you can afford.
Recommended: Are solar batteries worth it?
The 5 Best solar batteries that we recommend
1. Huawei LUNA2000
- Type: Lithium iron phosphate
- Battery capacity: 5 kWh (scalable to 10 or 15 kWh)
- Usable capacity: 100%
- Power ratings (peak/continuous): 3.5 kW/2.5 kW
- Efficiency: ~90%
- Warranty: 10 years but can be extended to 15.
The Huawei LUNA2000 is, overall, our most recommended battery for new installations.
Highlight the new part because this battery is only compatible with a few other Huawei inverters. If you don’t already have those inverters, then adding this to your existing solar system isn’t practical. You’d have to spend more to replace other parts.
With that out of the way, the Huawei LUNA2000 offers excellent value for money. That’s what the brand is known for in the world of electronics, after all. Plus, the warranty is hard to beat.
Moreover, the battery’s capacity allows you to use all of the stored energy and has wonderful power ratings. Although, efficiency is only an estimate based on what Huawei LUNA2000 owners are saying. Huawei didn’t disclose that information for some reason.
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2. Tesla Powerwall 2
- Type: Lithium ion
- Battery capacity: 14 kWh
- Usable capacity: 13.5 kWh
- Power ratings (peak/continuous): 5 kW/7 kW
- Efficiency: 90%
- Warranty: 10 years
The only reason the Tesla Powerwall 2 fell to 2nd on our list is its hefty price. It is far more expensive than the Huawei LUNA2000.
Disregarding cost, though, the Tesla Powerwall 2 is as reliable as they come. I mean, come on. It’s Tesla. Reliable is the company’s pride and glory.
Also, its “unlimited cycles” warranty says that the battery should retain 70% of its capacity in 10 years, regardless of how many times its charged and discharged. That’s incredible. The caveat is that this only applies if the battery is used for self-consumption and backup power.
Plus, it takes up less space than the Huawei LUNA2000, looks better, and is compatible with far more inverters in case of a blackout. If money isn’t a problem, we highly recommend this.
3. BYD Premium LVS
- Type: Lithium iron phosphate
- Maximum capacity: 4 kWh (scalable to 256 kWh)
- Usable capacity: 100%
- Power ratings (peak/continuous): 4.6 kW/3.3 kW
- Efficiency: 95%
- Warranty: 10 years
In many ways, BYD is the opposite of Tesla. While Tesla began with automobiles before entering battery storage, BYD started with solar batteries before they made cars. The price of their solar batteries is far more affordable, too.
The BYD Premium LVS’s storage capacity is also scalable, so it caters to a wider range of households. Its usable storage capacity, power ratings, efficiency, and warranty are also up to par with our standards.
Although, scaling this up to 12 kWh to compete with Tesla’s 14 kWh also makes it significantly heavier. This shouldn’t be a huge issue if it’s only going to stay in one place, though (i.e. residential applications).
4. Sungrow SBR battery
- Type: Lithium iron phosphate
- Battery capacity: 9.6 kWh (scalable to 25.6 kWh)
- Usable capacity: 100%
- Power ratings (peak/continuous): 6.6 kW/5.76 kW
- Warranty: 10 years
Like BYD, the Sungrow SBR battery is from China – but don’t let that stop you.
For one, it uses LiFePO4 so it’s safe. Sungrow also has had an office in Sydney for about a decade now. That tells you it’s more than capable of catering to the Australian market.
That said, the Sungrow SBR battery system is stackable. The specs you see here are for 3 modules. Although, you can stack as many as 8 modules for a maximum storage capacity of 25.6 kWh. Most residences won’t need that much energy, though.
It’s also one of the most affordable options out there given its magnificent specs. The reason it isn’t higher on this list is that Sungrow didn’t disclose its efficiency. Consumer data isn’t all that reliable here, too, but it should hover around 85-90%.
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5. Enphase IQ Battery 10
- Type: Lithium iron phosphate
- Maximum capacity: 10.5 kWh
- Usable capacity: 10.08 kWh
- Power ratings (peak/continuous): 5.7 kW/3.84 kW
- Efficiency: 96%
- Warranty: 10 years
To be clear, Enphase also has the IQ Battery 3 which is a smaller version of this. It offers similar specs after adjusting for capacity. So, you might want to consider that if you don’t need a lot of stored energy.
Anyhow, the best thing about these batteries is that it’s unlikely that you encounter any compatibility issues. This makes the process of building or upgrading solar systems so much easier.
Plus, the efficiency and warranty on these things are impressive. All things equal, Enphase solar batteries are the most efficient on this list. The warranty also says that this battery system should retain 80% of its max capacity after 10 years. Again, that’s the best on this list.
The reason it fell to 5th, though, is its power ratings aren’t anything to write home about. We think it’s a huge blow especially since it’s capable of storing enough energy to power the average Australian household.
Enphase IQ Battery 10 spec sheet.
Conclusion
To recap, the best solar battery storage for your home is the one that gets you the most value for your money and solves your problems.
You do have a few factors to consider, though, and that includes the size you need, the life of the solar battery, its power ratings, and its efficiency. All those factors are discussed above. So, feel free to check back in if you’re ever confused.
If you have any more questions about solar systems, you can refer to our Solar 101 guide. Or, when you’re ready to take the next step, we have a network of pre-vetted installers that are ready to give you 3 FREE quotes right away.
