What is a home battery?

Last updated on June 21st, 2022 at 03:28 pm

In the same way that cars can have batteries, so you are now able to install a battery in your home. It doesn't specifically have to be for your EV, but the rise in EV adoption (and the crazy differences in the price of electricity at different times of the day), has definitely increased demand for this kind of storage. So what is a home battery, how much do they cost, what kind of storage do they provide and should you get one? WhichEV takes a look at these questions and more.

In the same way that a petrol tank used to act as a buffer between your car's engine and the petrol station, so a home battery can sit between your home's electrical needs and the grid. However, there is one big difference. Traditional cars only ever take fuel from the pump. Modern power grids can (but not always), work in both directions – allowing you to sell electricity back to the grid.

In terms of size, the smallest home batteries come in at a little over 2kWh and are really only there to provide back up for your lights, fridge and freezer in times of emergency. Larger systems will store up to 15kWh, cost close to £8,000 and can play an important part in your EV's life, as well as your home finances. There are options for almost every budget/power requirement.

Home batteries tend to come with a long warranty – typically close to 10 years.

If you are planning on installing a home battery, then you should also think about how you are going to charge it. Maybe you have an economic plan with your main supplier so you can buy kWh cheaply overnight for five to seven hours.

Alternatively, if your roof lies in the right position so you can install enough solar panels to give you 3kW to 10kW – then you really can begin your move off the grid. This kind of installation would typically cost you between £5,000 and £9,000.

Before planning to spend £12,000 or more on solar panels and batteries, you really need to do your calculations on the kind of return you can expect over a ten year period.

Many people ask: “Can I make money from my electricity supply?” and the short answer is ‘Not really'. Suppliers will likely sell to you for an average of 25p per kW, while offering to buy for less than 5p/kW. There are various challenges to this process going on at the moment – so it's possible that in some ‘new and improved' version of the future, we will be able to buy in 10kWh for 50p and sell it back for £2.50 every day for a year – clocking up a tidy profit – but that's not likely to happen any time soon.

Getting solar panels installed will probably set you back between £4,000 and £7,000 for a typical house. This will let you reduce the power you take from your supplier – especially at peak times. Bear in mind that it will take a long time to pay off the ‘Battery + Panels' cost, which could be between £7,000 and £13,000 (or even more) combined.

Tesla owners with a decent sized roof, might be tempted to buy a Solar Roof and Powerwall – creating a complete home charging system with a long warranty

Having protection against the elements, dodgy supplies and fluctuating prices might be enough for you to want to invest in a home battery. It might also be the case that you just want to be as independent as possible – with the fewest monthly outgoings.

In any event, a home battery can make a lot of sense if you are an EV owner, but make sure you get advice from a number of reputable companies before you make your purchase.

In the future, it might become a legal requirement for new housing to come with solar panels and in-home battery storage.