Solar Panels: What size of battery storage system do I need for a family of four?

Having a battery storage system is essential to get the most out of your solar panels. 

Storage batteries allow you to store any excess electricity that your solar panels generate when the sun is out for use outside of daylight hours, making your household less reliant on the grid and lowering your bills. 

Just like solar panels, battery storage has an upfront cost but require very little maintenance once installed. The kind of battery storage you will need depends on a variety of factors, such as the amount of energy you consume and the number of people living in your household. For example, you will need a higher-capacity battery for a family of four than a single-person household.

In this guide, we take you through the ins and outs of battery storage to help you understand your household’s energy consumption and what would be best for you!

How much energy am I using?

The first thing you need to work out is how much energy your household is using so that you can get an appropriately sized battery storage system for your needs. There are a few ways to do this on your own:

• If you have a smart meter, it can calculate your electricity usage. 
• If not, you can check your monthly energy bills. Find the monthly consumption figure and divide it by the number of days in the month to work out your daily usage.

Don’t worry if you’re struggling to understand your energy consumption, during the quotation process for solar panels we’ll evaluate your energy usage and consider other factors like your local environment and the location of your solar panels to help you find the right size of battery storage.

According to The Eco Experts, an average family of four in a three-bedroom house will need an 8kWh battery. Installing one or two batteries is typically enough for the average four-person household, but you may need more if you want to live entirely off the grid.

How powerful is your solar power system?

When deciding on the size of storage battery you need, you should also consider how powerful your solar power system is and how many panels you have.

You’ll need to generate enough energy to charge your storage batteries so that you can use this solar power at night when your panels aren’t absorbing sunlight.

Ensuring you have the right size of battery storage will enable you to make savings on your energy bills and will even allow you to sell excess energy back to the grid.

Go smaller or go bigger?

There are advantages and disadvantages to choosing a storage battery slightly above or slightly below your energy needs. 

Batteries with a smaller capacity take up less space, so they’re ideal for houses with limited space. However, they won’t store all of the power you generate from a powerful solar panel system.

Buying an oversized battery is a good idea if you think you’re going to increase your energy consumption in the future; for example, if you want to install an electric vehicle (EV) charging point. 

However, there’s no need to get a larger-capacity battery if your solar power system won’t be able to charge it. Consistently undercharging your battery can cause damage in the long term.

Lead acid battery or lithium battery?

There are two kinds of storage batteries you can choose to complement your solar panel system: lead acid or lithium. 

• Lead acid batteries are popular because they are cheaper and easier to make, but they can be more difficult to use and maintain. 

• While lithium batteries are more expensive, they are far more efficient and long-lasting.

At Cerretti Electrical, we believe in providing the best products and services to our customers so they can get the most out of their solar panels which is why we install Lithium Battery Storage systems.

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We hope that this blog has helped you to better understand how storage batteries work alongside solar panels, and the different factors that you should consider before you commit to installing a battery storage in your home.

At Cerretti Electrical, we know that every household is different – that’s why we include an energy usage evaluation as part of our solar panel consultations. Our expert team will help you understand how much energy your household consumes and offer professional advice on what kind of battery is the right fit for your home. 

Find out more about our solar panels and battery storage systems here or contact us about a consultation here.