M&E Contrax Resources

Solar Battery Storage

Resource Highlights:

A solar battery stores surplus electricity so you can use more of your own solar power later.

Batteries are often most useful for homes with higher evening usage, or anyone aiming for greater energy independence.

The right battery size depends on your usage pattern and how much surplus your solar system produces.

What it is, how it works, and whether it is worth it for your property

Battery storage helps you get more value from your solar panels by storing surplus electricity generated during the day, so you can use it later when your panels are not producing, typically in the evening and early morning. For many households and businesses, a battery can increase self consumption, reduce grid reliance and improve overall savings.

This guide explains how solar batteries work, who they suit, what affects performance, and what to consider before you install one.

What is solar battery storage?

A solar battery is a storage unit that holds electricity generated by your solar panels. Instead of exporting surplus power to the grid, your system can charge the battery and then discharge that stored energy later.

It is important to note:

a battery does not increase how much electricity your solar panels generate

it increases how much of that electricity you can use yourself

That is why batteries are often described as a way to improve self consumption.

How does a solar battery work day to day?

Most solar and battery systems follow a simple order:

Your solar panels generate electricity

Your home or business uses solar power first

Any surplus charges the battery

Once the battery is full, additional surplus is exported to the grid

Later, when generation drops, the battery supplies power to your property

Many modern systems include monitoring, so you can see generation, battery charge and discharge, and grid imports and exports.

Who benefits most from battery storage?

Homes with higher evening electricity use

If you use most electricity after work hours, a battery can shift daytime solar into the evening, which can increase savings.

Properties with steady base load

Homes with constant demand from appliances, home working setups, or equipment running through the day can also benefit, especially when surplus is predictable.

Customers looking for more independence

Some people value reducing grid reliance as much as they value bill savings. Battery storage can support that goal by covering more of your daily usage.

Businesses with a suitable load profile

Battery storage for businesses can be useful where:

demand peaks at certain times

the site wants better control of energy use

there is a desire to reduce imports during higher cost periods

A good design is based on real site data.

Is a solar battery always worth it?

Not always. A battery delivers the most value when you have enough surplus solar to charge it and enough evening usage to discharge it meaningfully.

A battery may be less beneficial if:

you already use most of your solar electricity during the day

your solar system is small with little surplus

your evening usage is low

the battery is oversized and rarely cycles

This is why battery sizing matters, it should match real use, not assumptions.

What size battery do you need?

Battery sizing is based on two key questions:

how much surplus solar do you produce on a typical day

how much electricity do you use in the evening and overnight

A good installer will review:

annual usage and daily patterns

typical solar generation for your roof

likely self consumption with and without a battery

whether you plan to add EV charging or other loads

The goal is to choose a capacity that regularly charges and discharges, rather than sitting underused.

Do you need a hybrid inverter?

Many battery systems use a hybrid inverter, which is designed to manage both solar generation and battery storage. Some existing systems can add batteries later, but it depends on inverter type and overall system design.

If you are installing solar now and may add a battery later, it is worth choosing a battery ready design from the start.

Batteries, export payments, and SEG

Without a battery, you may export more electricity to the grid and receive export payments through a tariff such as SEG.

With a battery, you often export less because you store more for your own use. This usually increases self consumption and can improve savings, but it may reduce export payments.

The best system design balances:

reducing imports from the grid

making good use of stored energy

exporting surplus where appropriate

Find out more about the Smart Export Guarantee here

How long do solar batteries last?

Battery life depends on:

battery type and build quality

how often it cycles, charges and discharges

operating temperatures and installation location

warranty terms and usable capacity

A good installation includes clear warranty information and monitoring so you can track performance over time.

Find out more about battery storage here

Simple ways to get the best from a solar battery

Use monitoring to understand your daily patterns

Run high load appliances when solar is generating, where practical

If you have an EV, explore smart charging so charging happens at the most cost effective times

Avoid oversizing, a battery should be used regularly

Choose a tidy, ventilated installation location suitable for long term performance

Frequently Asked Questions

Often yes, but it depends on your inverter and system design. A quick review can confirm compatibility and the best approach.

Not automatically. Many systems switch off during an outage for safety. Backup requires specific configuration and, in some cases, protected circuits.

Typically yes, but results vary by season because solar generation is higher in summer and lower in winter. A good design considers year round patterns.

It can be, especially if you know you need it for evening usage. However, some customers install solar first and add a battery later once they have real monitoring data.