Solar Battery Guide

Getting a solar system without a solar battery no longer makes sense. Installing a solar battery in your home provides greater energy independence, frees you from blackouts, and potentially saves you a tonne of money in electricity bills.

Still learning about solar batteries? Here are answers to some of the common questions we’re asked. We've also linked articles that provide additional educational content on solar batteries.

Why should I get a solar battery?

The reasons you should get a solar battery are a decline in the value of feed-in tariffs, greater energy independence, and to save money on electricity bills.

Feed-in tariffs

Feed-in tariffs are the payment you receive for each kWh of energy you send to the electrical grid. Household solar systems that don’t have a solar battery can’t store the excess solar energy generated during peak times, so they have to send it to the electrical grid. In the early days of solar, feed-in tariffs were high, meaning that a household received enough cashback during peak solar energy generation periods to cover the cost of pulling electricity from the grid in the evenings. 

In 2023, feed-in tariffs are as low as 2.25 cents between 9 pm and 3 pm. This means that households aren’t making enough to cover the cost of the electricity they pull from the grid, leading to a household’s electrical bills remaining high. 

Read our article about feed-in tariffs.

A solar battery means energy independence.

Installing a solar battery means that even when your solar energy generation is low because it’s the evening or cloudy, you’ll be able to power your home with the energy stored in your battery. Additionally, as the cost of electricity continues to rise nationally, you’ll save big by not having to pull your electricity from the grid; after all, solar energy is free!

What size solar battery do I need?

The solar battery size you will need depends on your energy consumption, budget, and roof space. How many solar panels you have installed directly influences what size solar battery to purchase. 

You need to ensure you get the right-sized solar battery for your home. If you get an undersized battery, you won’t be able to store enough solar power to power your home for a meaningful amount of time. On the other hand, getting an oversized solar battery would mean that you’ve paid for a battery able to hold more solar energy than you can generate. 

To avoid getting a solar battery that is too small or too large, you need to calculate for specific needs. Some factors that impact what size solar battery you’ll need are your overall energy consumption, the number of solar panels, and your budget.

Read our article What Size Solar Battery Do I Need? for a detailed analysis of calculating the optimal solar battery size.

How much are solar batteries?

Solar batteries can cost anywhere between $4,500 to $18,000. The cost of a solar battery varies depending on capacity, cycle life, and depth of discharge, among other factors. There’s also the cost of an inverter to consider, as solar batteries need a dedicated inverter (preferably a hybrid inverter). Some solar batteries will come with a built-in inverter, and some you’ll need to purchase separately, adding to the overall cost. You also need to remember that installation is an additional cost on top of the price of the battery. 

Partnering with Plico is a little different – we’ve disrupted the solar industry with no big upfront costs and just one low weekly fee. View our Products & Pricing for more information.

Read our article How Much are Solar Batteries? for a comprehensive discussion of solar battery costs.

What type of solar battery should I choose?

The majority of solar + battery systems incorporate a lithium-ion solar battery. Lithium-ion solar batteries dominate the market because of their versatility, durability and longevity. They have some of the highest cycle lives and are used in small-scale and large-scale systems.

Other less common solar battery types are lead-acid, flow and hydrogen. 

Learn more by reading our article on the different types of solar batteries.

What is the difference between lithium iron phosphate (LFP) and nickel manganese cobalt oxide (NMC) solar batteries?

Lithium Iron Phosphate (LFP) and Nickel Manganese Cobalt Oxide (NMC) are two popular types of lithium-ion batteries used in solar battery storage systems. They differ in chemistry, performance characteristics, and specific use cases:

Safety: LFP batteries are considered safer, more resistant to thermal runaway, and have higher thermal stability. Meanwhile, NMC batteries are relatively more prone to thermal runaway and can suffer issues from overheating. 

Chemistry: LFP batteries use lithium iron phosphate as the cathode material, while NMC batteries use a combination of nickel, manganese, and cobalt.

Energy density: LFP batteries have a lower energy density, making them bulkier and heavier than NMC batteries, which offer higher energy density in a given size or weight.

Cycle life: LFP batteries typically have higher cycle lives and longer lifespans than NMC batteries.

Cost: LFP batteries are generally cheaper due to less expensive and more accessible materials, while NMC batteries are expensive because of the higher cost of nickel, cobalt, and manganese.

Overall, in solar + battery systems, LFP batteries are preferred for safety, longevity, and cost-effectiveness. Plico’s systems currently use two different types of solar batteries, both of which are LFP batteries. We’re a technologically-agnostic company, meaning that we’re continuously reassessing and ensuring we’re providing members with the best equipment on the market.

What should I look for in a solar battery?

The essential categories that separate an elite solar battery from an average one are capacity, power, depth of discharge, round-trip efficiency, lifespan, and cost.

Capacity

A solar battery’s most important factor is how much energy it can store. The capacity of a solar battery is measured in kilowatt-hours (kWh), and you want to ensure it matches, on average, the amount of energy you would have otherwise exported.

Power

The power of your solar battery is how much electricity it can output at once. A solar battery will have two types of power ratings: continuous power and peak power. Both power ratings are measured in kilowatts (kW).

Continuous power is the amount of electricity a solar battery can continuously supply. An example would be running an appliance like a fridge.

Peak power is the total power your solar battery can output at one time. Peak power is useful for appliances that need a lot of power to get going, such as an oven or washing machine.

For solar batteries, both continuous and peak power are important, so you don’t want to privilege one over the other. Fortunately, plenty of quality lithium-ion batteries on the market have excellent continuous and peak power outputs.

Depth of discharge (DoD)

Depth of discharge is how much of a solar battery’s capacity can be used without degrading the battery’s health. For example, Pylontech’s US3000 has a DoD of 90%, meaning it can discharge 3.2 kWh of 3.55 kWh for each stackable unit (maximum capacity is 25.6 kWh from 28.4 kWh). 

Round-trip efficiency

A solar battery’s round-trip efficiency is how efficiently the battery can store the solar energy your solar panels generate. Solar energy is always lost in transfer, but particular solar batteries are more efficient in retaining energy. For example, if a solar battery’s round-trip efficiency is 85%, that means that for every 10 kWh of solar energy pushed its way, the battery stores 8.5 kWh.

Lifespan

Solar batteries have a lifespan of between five to fifteen years. A solar battery’s lifespan varies depending on the battery type and is integral to getting the most for your money. Unless you’re partnering with Plico and paying one low weekly fee, solar batteries can pose a high upfront cost. Make sure you research and find warranty details, reviews, and any other contextual information that indicates the average lifespan of your prospective battery choice.

Read our article How Long Do Solar Batteries Last? for more information. 

How do solar batteries work?

A solar battery stores the energy generated by the system’s solar panels. This is more complex than it sounds, with a battery needing a designated inverter to change the electrical current each time it discharges. Here is the process of how a solar battery works.

1. Sunlight beams down on your solar panels.
2. Solar panels absorb the sunlight and create direct-current (DC) power.
3. DC power is pushed to the solar inverter.
4. Solar inverter converts the energy to alternative-current (AC) power (so that it can be used by your household appliances).
5. AC power is sent to the switchboard.
6. Switchboard directs the electricity to household appliances.
7. Solar energy excess goes to the solar battery without being converted to AC power.
8. Solar panels aren’t producing enough energy to meet the electricity demands, so the solar battery sends energy to the inverter.
9. Inverter converts the DC power into AC power. 
10. Switchboard sends the electricity to the required appliances.
11. Solar battery becomes empty, and the property pulls energy from the grid.
    
    

Read our article How Do Solar Batteries Work? for more information. 

What is a community battery?

A community battery is a solar battery that is installed and connected to multiple houses in a neighbourhood. Households can store their excess solar energy in the community battery, pooling it together and accessing the power when needed. Community batteries are still in the early development phase, and the distribution method is under continuous refinement to ensure that it’s fair for all participants.

Read What are Community Batteries? to learn about the future of shared batteries.

Should I get a community battery or a household battery?

Community batteries are an exciting prospect in the future for households who can’t afford to purchase a solar battery. However, having the energy independence of your own solar battery is preferable. Community batteries will likely be a subscription-based payment model. But if you partner with Plico, you can own a solar battery and only pay one low weekly fee.

Can a solar battery charge my electric vehicle?

A solar battery can charge your electric vehicle (EV). You just need to ensure you’re generating enough solar power with the right-sized solar + battery system. 

Electric vehicles have risen to prominence because they’re more environmentally friendly than petrol and diesel cars. However, the electrical grid is powered by coal and gas power plants, so charging an electric vehicle with power from the grid harms the environment. A solar + battery system is the only environmentally friendly way of charging an EV, and a solar battery will allow you to charge your EV even when the sun isn’t out.

Learn more by reading our articles on charging an EV with solar and how much it costs to charge an EV.

What household appliances can I run with a solar battery?

Your solar battery can run all your electrical appliances with solar power. A solar battery is the cheapest way to power your home when it’s evening or overcast, and your solar panels cannot generate the required electricity. The best time to run appliances with solar power is during peak generation times. The optimal solar window is 10 am - 2 pm. However, some appliances will need to operate outside this period, and that’s where your solar battery will help.

We break down powering your home appliances in our article What Appliances Can be Run on Solar Power?.