Batteries & Smart Grids

A solar battery allows you to store your generated solar electricity so you can use it anytime, day or night


Change is happening, and it’s happening fast.  We are beginning a transition to an electrified future, where transport demand, as well as loads in buildings, is met by decentralised renewable energy.  With much of the renewable generation being intermittent in production, battery storage is going to be an essential part of future electricity systems and the buildings connected to them.  We envisage a future where individuals and businesses will be using, generating and storing their own electricity; buying and selling from each other to manage demands on the grid collectively through smart grid technology.

The key technologies to make this happen –  electric vehicles, solar panels and battery storage – already exist and are reducing in cost dramatically.  Newer concepts such as vehicle-to-grid, time-of-use electricity tariffs, peer-to-peer trading of electricity and local electricity markets are also close to a breakthrough.

Put all this together, and storage offers households and businesses a great opportunity.  A solar panel battery system makes you more self-sufficient, helps speed the transition to renewables, and can reward you for helping to manage the UK electricity system.

Be more self-sufficent

Store electricity to run your home at night

 Or even power your car

Never have a power cut

  Store cheap night-time electricity

  Get paid for keeping the grid stable

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Multi-Award winning Installers of Solar PV, Battery Storage, and EV Charge Points

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For many of our solar PV customers, getting a home battery system is the obvious next step.  Working families who are out during the day are especially aware that although they are generating their own clean green power, they don’t get to use it themselves.  A solar battery system can dramatically increase the percentage of solar electricity that gets consumed within the home.  It makes you more self-sufficient, and you can go for months without buying electricity from the national grid.  Some home batteries now come with the ability to ride through power cuts, so your supply of electricity is entirely secure.

Others take a broader viewpoint – by storing solar electricity and using it in the evening, it reduces the peak demand on the UK electricity system.  That means we need less fossil-fuelled power stations on the network, and that’s another step forward in the energy transition to renewables.

Solar batteries are also vital if you would like to use your home solar PV system to run your car on sunshine.  If you are out at work in the day, a home battery will store electricity for you, which can then be transferred to your car battery when you arrive home and plug in.  That way you get zero-carbon transport as well as powering your home.

Solar battery technology is also forming a perfect partnership with electricity suppliers offering new types of tariff.  A time-of-day tariff – which gives you cheaper electricity at night – allows you to charge up your battery with cheap electricity at night, as well as from the sun during the day.  Some suppliers have gone even further by offering real-time pricing, where the price varies throughout the day.  It might be low, for example, when lots of offshore wind generation supplies the grid.  Batteries smartly charge when they detect this.  It’s a great way to make sure your bills are as low as they possibly can be.

Home Battery Basics

How does a home battery work

How does a home battery work

Find out how a home battery works, and how this changes throughout the year

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home battery, power cut, power outage

Using a home battery in a power cut

Here’s how you can use a home battery to ensure you never go without power again.

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Ac Coupled, DC coupled batteries

AC vs DC Coupled Batteries

Our explanation of the two methods of connecting batteries to a PV system

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Our Solar Home Batteries

Tesla Powerwall, home battery

Tesla Powerwall

The Tesla Powerwall is the world’s leading battery technology – large capacity alongside Tesla’s elegant design

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SolarEdge, Energy Bank, battery, 10kWh

SolarEdge Energy Bank

The Solar Edge battery is DC coupled and integrates seamlessly with their inverters

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GivEnergy are a British manaufacturer offering a 9.5kWh system – at very competitive prices

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Get in touch with our battery experts about your home storage project


Joju is an independent company. We’re not wedded to any one storage technology or provider, and we are able to give you clear and impartial advice about the options available.

Battery systems are more complex technically than you may assume, and sizing the system appropriately is crucial.  Buy a battery that is too small, and you won’t capture all the soalr energy you could, or run your home as long as you could.  Buy a battery that is too big and you’ll have bought storage capacity you’ll never use.

A sound technical solution is needed so that components work together to deliver what you are expecting. That’s why we bespoke design every battery storage system we sell to suit your needs.  We strongly believe there is no such thing as an off-the shelf battery storage solution.

We offer a range of home battery storage systems from a wide range of manufacturers, including Tesla PowerwallSolarEdge, and GivEnergy.  This is not an exclusive list, and we are happy to install other brands upon request.

  • fully charged, robert llewellyn
    Glenn gets Fully Charged
  • commercial battery storage, sonnen, repower balcombe, sussex, Eco8
    Commercial Battery Storage at Turners Hill School
  • Stuart’s two-staged install
  • Sunpower, Tesla, Powerwall2, installation
    Robert Llewellyn’s Home of the Future
  • Tesla, powerwall, ev charging, electric vehicle
    Chris’s Complete Set
  • Rotherham, Metropolitan, Borough, Council, Wellgate, car park, solar PV
    Rotherham Metropolitan Borough Council’s Full Set
  • solar roof tiles, integrated solar, BIPV, ThamesWey
    ThamesWey’s Innovative Battery Microgrid
  • Solar and Storage at the University of Wales Trinity St David
  • Project ERIC



If you are buying a home battery alongside solar, or on its own, our process is the same. We’ll discuss with you what you want to achieve wit your solar battery project – in terms of self-sufficiency, running electric vehicles and riding through powercuts.  This conversation will allow us to present you with a range of suitable products that you could use.

Once you have decided to go ahead, there is one hurdle to be jumped.  Most battery systems need a grid connection application to the local network operator. We’ve made thousands of thse applications, so it’s no problem for us to submit this on your behalf.  Rejections are very rare, but it does take up to 8 weeks to come back with a response.

Once approved, we’re all good to go. We’ll book in one of our electrical teams, who will undertake the installation, commissioning and handover of your home battery system.


Find out more about how we manage home installations here.

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Advanced Home Battery Knowledge

is solar worth it, payback, returns on investment

Are batteries worth it?

Our straightforward facts and figures on the economics of owning a home battery

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Electricity Tariffs

Tariffs for the Renewable Home

Maximise the financial benefts of a home battery by combining it with innovative electricity tariffs.

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Run Your Car On Sunshine

Run Your Car on Sunshine

Find out how to utilise a home battery system to power your electric car, even if you are at work in the day

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Octopus Flux

Octopus Flux

Earn money from your battery by discharging to the grid at peak times

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Find out if Tesla’s new Powerwall 2 is the right battery for you:

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    Turners Hill School, Sonnen

    Turners Hill School

    Turners Hill School features 3 Sonnen batteries that perfectly cover their evening and nigh-time usage

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    Rotherham Metroploitan Borough Council, car park, EV charge point, solar, battery, Tesla

    Rotherham’s Complete Set

    Rotherham Council used battery storage alongside EV chargeing and solar arrays in this holistic non-domestic system.

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    It’s not just solar home battery systems – battery technology will be deployed throughout smart grids at all scales.  However, commercial-scale battery projects have unique challenges.  Most notably, loads in commercial buildings tend to be high during the day, so on-site solar generation is used directly in the building, without the need for storage at all.

    There are, however, additional markets that can be accessed by larger projects, called ancillary services.  The grid operators have a range of functions they need to provide, on top of moving electricity around.  These include maintaining a stable frequency, and ensuring back-up power is brought online in the event of a fault.  Battery owners can be paid handsomely for providing these ‘ancillary services’ to the grid.  You might get paid for providing a short burst of power in an emergency, or be rewarded for keeping the grid frequency stable.


    Whilst individual homeowners or commercial premises will benefit from using a battery system, the real benefits for this come from aggregating together at a system level.  This involves communication between devices and their coordination to maintain a balanced system with benefits for everyone.

    We’re working on some innovative smart grid projects at present.  Our first demonstrator project is a microgrid of 14 solar-powered homes in Woking.  We have installed a centralised storage system at the substation serving these homes.  The benefits of aggregation, in conjunction with the electricity tariffs on-site, combine to give one of the most cost-effective

    We’re also working with our long-term community energy partners the Low Carbon Hub on Project LEO –one of the most ambitious, wide-ranging, innovative, and holistic smart grid trials ever conducted in the UK.  It is looking at how households, businesses and communities can benefit from the coordinated deployment of generation and storage assets across Oxfordshire.

    Thameswey, Woking, microgrid

    Thameswey’s Microgrid

    This centralised battery storage project in Woking serves an estate of 14 solar homes

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    Project LEO, Oxfordshire

    Project LEO

    We’re assisting our project partners, the Low Carbon Hub, on this ground-breaking smart grids project.

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    Talk to our commercial projects team about smart grids or commercial battery storage on 0207 697 1000