Home Battery Storage and EV Charging: How They Work Together

Home battery storage is becoming more common in London, often alongside solar panels or a time-of-use tariff. Many homeowners with an electric car ask whether a home battery can help charge it. The answer depends on the size of the battery, the tariff and how you drive. This post explains how a home battery and an EV charger can work together.

What a home battery does

A home battery stores electricity to use later. It can be charged from solar panels during the day, or from the grid overnight on a cheaper rate, then power the house in the evening. Most home batteries are much smaller than a car battery, so they can only add a modest amount of range to an EV.

Charging the car from the battery

Using a home battery to charge a car is possible, but often not the best use of it. A full car charge can empty a home battery quickly, leaving the house to draw from the grid at peak prices. In many homes, the better approach is:

• Charge the car directly overnight on a cheap tariff.
• Use the home battery to run the house during the expensive evening hours.
• Send surplus solar to the car on sunny days, if you have panels and a compatible charger.

Our post on solar panels and EV chargers together covers the solar side.

Settings matter

Some chargers and batteries can be set so the battery does not discharge into the car. Check this when the system is set up, so a night charge does not drain the battery you were saving for the morning. A smart charger can also be scheduled around your tariff. See our guide to smart charger rules.

Supply and consumer unit

A home battery, solar inverter and EV charger all connect to your consumer unit, and the network operator usually needs to be told about batteries and solar. A survey checks there is space and suitable protection. See our guide on whether you need a new consumer unit.

Plan it together

If you are planning a battery and a charger, it is usually cheaper and neater to design them at the same time, with cable routes and protection chosen for both.

Energy North Ltd installs home chargers across North, East and West London with City & Guilds certified electricians. See our EV charger installation page to book a survey.