What Size Solar Battery do I Need?

Solar panels are great sources of renewable energy, and installing a hybrid solar panel system can be incredibly beneficial. It provides you with the opportunity to produce electricity with your solar array and store it in your solar battery for future use. When you first start looking into solar batteries and hybrid solar systems, you might find yourself wondering: what size solar battery do I need? After all, it isn’t a cheap investment, and you want to make sure you have the right-sized solar battery for your home!

If you’re looking into getting a solar battery, we spoke to Skylamp Solar to find out what you need to know about solar batteries, their size, and how to pick the right solar battery for you.

How are Solar batteries Measured?

The first thing to get your head around is how exactly solar batteries are measured. A solar battery will not be presented in hours of use, so it’s important to know what the stats for each solar battery mean. Consulting a reputable Solar Company can provide invaluable guidance in understanding these metrics, assisting you in making informed decisions when choosing the most suitable solar battery.

Solar batteries are measured by their capacity to store energy. That being said, you do not want to use a solar battery completely – using a battery’s full capacity can damage it. Instead, you should expect to use around 90 to 95% of the capacity. This is called the depth of discharge (DoD).

In addition to considering the size of the solar battery you need, you should also think about the output of your battery system so that you can actually use your solar panel system to power your home.

How to Determine What Size Solar Battery You Should Get

Once you’ve got your head around how batteries are presented, you’ll be ready for the answer to your first question: what size solar battery do I need? Well, here’s how to determine that.

Consider the Size of Your Home

Different-sized homes will need a different-sized solar battery to keep the solar panel system running effectively. This is because the larger the home, the more energy usage.


Generally speaking, an average one-bedroom property will be fine with a 2 kWh solar battery. A two-bedroom property will need a 4 kWh solar battery, a three-bedroom will need 8 kWh, and a four-bedroom will need approximately a 9.5 kWh solar battery.

These are based on the average energy usage for each property. If, however, your energy usage is different, your ideal solar battery size may be different. Likewise, your solar battery storage requirements may differ depending on the size of your solar panel system.

Top Tip: Before You Begin to Look at Solar Panels or a Solar Battery System, Calculate Your Power Usage

This will help you to determine the desired power output of your solar battery storage and will tell you how much electricity you need your solar panels to produce to get you completely off the grid. Figuring this out is much easier with a smart meter, but if you don’t have one, you will need to use your bill and divide your total usage by days in the month.

It’s considered good practice to get a battery that will store energy from your solar system equal to just over your average use.

Consider Your Solar Panels

In addition to the energy usage your property has, you should also consider the solar panels you have/can afford to get. If your roof space is small and you only have room for a 4kWp solar system, for example, then you will need a battery with around 8kW capacity. That is around how much a 4kW system will make each day.

For each common size of solar panel system, here is the recommended battery capacity:

  • 5kW solar panel system: 9.5 – 10kW solar battery
  • 6kWp solar panel system: 12kW battery
  • 8kW solar system: 16kW battery storage system
  • 10kW solar panel system: 20-21kW battery

These are the most efficient battery sizes for each solar system, allowing you to use the battery storage system as effectively as possible to store excess energy created by your solar PV system.

You need a solar battery whose battery storage will be filled by your solar panels during the day and whose output is going to actually match the output you need to power your home.

Look at Battery Cycles

A solar battery will have a battery cycle attached to it. This shows you how many times the battery can be charged and discharged. You want a solar battery with a high battery cycle, as this means it will continue to store excess energy produced by your solar PV system and allow you to use it for a long time. Those with shorter cycles will not be able to store excess energy for as long as they will deteriorate and degrade.

Think About Whether You’re Staying on the Grid


If you’re looking to go completely off-grid, then you need a solar panel system with a battery system much bigger than average. For completely disconnected energy, your battery needs to have a very high capacity and a high energy output. Otherwise, your solar panels are not going to be able to support you on their own, and you will have to rely on a hybrid inverter to switch you between the grid and the solar power storage.

How to Get Your Solar Battery Storage System Set Up

The best way to plan and install a solar panel system with a battery that is the right battery size for you is to speak to a professional. They will be able to determine which of the battery storage systems will work best for you, and whether you can have one of the off-grid storage systems, as well as how many solar panels you can fit and if you’re going to get enough light.

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