Adding a battery to your solar panels? A checklist before getting a quote

You already have solar panels, and you’re wondering whether a battery would help you make more use of them.

Before choosing a system, you want answers to a few practical questions: will it work with what you have, what size would suit your home, and what would the installation involve?

A recent electricity bill and a few details about your solar system will help an installer give you a more useful answer. You don’t need to find every document before getting in touch. Start with what you have, and use this checklist to guide the conversation.

1. Decide what you want the battery to do

Think about what prompted you to look into battery storage. Are you out during the day and using more electricity in the evening? Planning an electric car? Interested in backup for particular appliances during a power cut?

Write down your priorities, including any that other people in your household have. These give the installer something concrete to assess.

For example: “We’d like to use more of our solar electricity after work, and we’re planning to get an electric car next year.”

If backup matters to you, say so explicitly. Ask which appliances the proposed system would support and what equipment that would require.

2. Have your electricity bill handy

Look for your annual electricity use in kilowatt-hours, usually written as kWh, and the rates you pay. The amount of electricity you use is more helpful than your monthly direct debit alone.

If your supplier’s app shows when you use electricity, that can add useful detail. Mention whether you work from home, run appliances overnight or have busy periods when several things are on at once.

Keep the date of your tariff details with the bill. If a quote includes estimated savings, ask which rates and usage figures it uses, and whether it assumes you will change tariff.

3. Find a few details about your solar system

Useful information includes the installation date, the inverter make and model, and any generation figures from your solar app or paperwork. The inverter converts the electricity produced by your panels into a form your home can use.

If you inherited the panels when you bought the house, tell the installer what you know. You don’t need to identify everything yourself or open any electrical equipment.

Ask a straightforward question: “Which parts of my existing system would stay, and which would need to change?” The answer should describe your installation and identify anything that needs checking at a survey.

4. Mention any payments you receive for solar electricity

If you receive Feed-in Tariff payments, read our five questions to ask before adding a battery to solar panels on a Feed-in Tariff.

Make this part of the initial conversation. Ask the installer to explain what needs checking about your current arrangement before work is agreed. A quote should identify unresolved questions rather than leave you to assume that everything will carry on as before.

5. Talk through the space and installation work

Think about where equipment might go, how that space is used and whether access is restricted. Mention any building work you have planned.

The installer should assess a suitable location. Ask where the equipment and cables would go, what work is included and whether the proposal depends on anything being confirmed at the survey.

If appearance matters to you, say so early. It is easier to discuss the position and cable route while the installation is being planned.

6. Ask why that battery has been recommended

The recommendation should explain how the system suits your needs. The Energy Saving Trust’s battery storage guide also advises that sizing depends on your circumstances and should be discussed with an installer.

Ask how your usage, existing solar system and future plans informed the choice. You should be able to understand the reasoning without having to interpret a specification sheet yourself.

Before accepting a quote, check that it answers three questions:

• What equipment and installation work are included in the total price?

• Which assumptions support any estimated savings?

• What warranties, handover and support are included?

Ready to explore your options?

Start with a bill, whatever solar information you have and a short explanation of what you want to achieve. You can work through the remaining questions with the installer.

Evoflo is based in Bridport, Dorset. If you’re considering adding a battery to your solar panels, tell us about your home and what you have in mind.