Battery Storage for Solar Power Systems

With a battery storage system, you can use your free solar power during the day, then draw down on your excess solar energy from your battery bank at night. Energy independence!

About Battery Storage

When Does It Make Sense To Install A Battery

Who doesn’t want a nil bill? Households and businesses alike want to be more self-sufficient and less reliant on the grid by storing clean energy generated by their solar panels.

At the moment, the greatest shortcoming of solar power is that you need to use your solar energy at the time that it’s produced to get the greatest benefit. Not everybody can take full advantage of their solar panels’ output. For example, a typical working family which has higher usage early in the morning and in the late afternoon/evening, as the graph below demonstrates:

This is where battery storage comes in.

There are 3 main reasons you’ll want to add batteries to a grid-connected solar power system:

  1. you want to store the excess energy that your solar power system generates during the day and then use this at night when your panels aren’t working.
  2. you want to have backup power available if the grid goes down (mostly applicable in regional areas).
  3. you’re tired of electricity tariff increases and want to cut the cord to the grid and never pay an electricity bill again.

If you’re unsure of the critical questions to ask when it comes to choosing and installing a battery, here’s our Battery Storage Buying Guide with the Top Ten Questions You Need To Ask.

Household Power Consumption

How Does Battery Storage Work

Here’s an example of how a system with a SolarEdge battery storage technology works.

Battery Storage System Layout

With batteries, both your daytime and evening electricity usage is free because:

  • any appliances that run during the day can run at zero cost direct from your solar panels; and
  • many appliances that run of an evening can also run for free, drawing your stored solar energy from your batteries

Can I Disconnect From the Grid When I Install a Battery?

Although we all like the idea of disconnecting from the grid altogether, for most households and businesses, it’s advisable to stay connected. This is because the cost of a hybrid system (where you have solar panels + battery storage + the grid as your backup) is so much cheaper than an off-grid system.

The cost of a typical off-grid or stand-alone system starts at about $45,000 for 16-17kWh of usable storage. If you’d like us to design an off-grid system for you, our accredited designers can do this for you. Just complete this Load Assessment Worksheet as thoroughly as you can and email it across to us.

How Much Do Battery Storage Systems Cost?

Size Brand Price
6.5kWh battery LG Chem $10,900
10kWh battery LG Chem $12,250
14kWh battery Tesla Powerwall 2 $13,550

You can hasten the payback period of your battery by installing a clever Australian-made technology called Reposit Power. It’s a simple-to-use energy trading system that allows you to charge your battery for free or at cheap rates and on-sell your power to the grid for a profit at peak times. It’s like a smart meter that works for you. Take a look at the video below to see how Reposit is working for one of our customers, based in the Northern Illawarra:

Battery size 6.5 kWh
Brand LG Chem
Price $10,900
Battery size 10kWh
Brand LG Chem
Price $12,250
Battery size 14kWh
Brand Tesla Powerwall 2
Price $13,550

You can hasten the payback period of your battery by installing a clever Australian-made technology called Reposit Power. It’s a simple-to-use energy trading system that allows you to charge your battery for free or at cheap rates and on-sell your power to the grid for a profit at peak times. It’s like a smart meter that works for you. Take a look at the video below to see how Reposit is working for one of our customers, based in the Northern Illawarra:

Different Types of Batteries

Hybrid vs Off-Grid?

With a hybrid battery solution, you remain connected to the grid. You use your solar panels during the day, draw down from your battery system overnight and have the grid as your backup if your panels and batteries don’t provides sufficient power to cover your consumption. 95% of customers in metropolitan areas will opt for this solution because hybrid systems are so much cheaper than off-grid systems.

As the name suggests, with off-grid systems, you are not connected to the grid. You use your solar panels during the day, draw down on your (larger) battery system when required and usually have a diesel or petrol generator as your backup.

You can choose to go completely off–grid (usually a minimum of $45,000), but this is generally only advisable if:

  • you’re building a new home in a regional area and it’s going to cost you as much or more to install the poles and wires to your home as it is to install an off-grid system
  • you get regular blackouts and/or brownouts
  • you want to be 100% self-sufficient as far as your energy needs are concerned

Storage Capacity

How Much Energy Can a Battery Store?

This depends on the brand of batteries that you buy, but most household battery storage units are capable of storing between 3.2kWh and 10kWh. When you use up the storage capacity of your batteries of an evening, you simply draw any remaining power from the grid.

What Size Battery Storage System Do I Need?

For most households, 10-15kWh of storage is ample for evening/overnight use.

If you can skew your energy consumption so that you’re using the bulk of your total energy during daylight hours you’ll only need a 6.5-10kWh battery. This is because you’ll have run your heavy-duty appliances directly from your solar panels during the day for free and will just be using your battery to power your fridge, lights, TV, standby power and computers at night.

If more of your usage is of an evening, then a larger battery storage unit (around 14kWh) would be advisable.

If you’re not sure how much of your overall consumption is during the day vs late afternoon/overnight, you can work out your energy usage profile by taking a note of your meter reading in the morning (eg. 8am) and again late in the afternoon (eg. 5pm) for a number of days. This will tell you how much energy you’re consuming during daylight hours vs overnight.

Battery Storage Savings

  • You can reduce your reliance on the grid by 80-100% with a solar + hybrid battery system.
  • You can reduce your reliance on the grid by 100% with a solar + off-grid battery system (+ a generator).

To provide you with an accurate solution, we highly recommend a Free Home Assessment.

Important Considerations

Who Should I Choose To Install My System?

More important than the quality of the components you choose is the quality of the installation, as batteries – especially lithium-ion – are highly combustible. It’s imperative to have your battery system installed by a professional who’s highly experienced and accredited (who’s been installing battery storage systems for at least 3 years).

Battery Storage Quotes

The Energy Experts takes the hard work out of installing a battery storage system. Our consultative approach means we understand your current and future needs and properly size and professionally install a high-quality battery storage system that’s guaranteed to outperform and outlast conventional equipment.

Although our home base is in the Illawarra, we have reputable and experienced battery installation teams in the Illawarra, the NSW South Coast (Tura Beach) the Shoalhaven (Nowra & Braidwood), Sydney (Gladesville and Auburn), the ACT (Canberra), the Central Coast (Tuggerah), Newcastle (Warabrook) and New England (Glen Innes).

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