Battery ESS (Energy Storage System)

No. A home battery can be installed with or without solar PV. Without solar, a suitable battery can charge from the grid and store electricity for use later.

Your home can use solar electricity as it's generated, while surplus electricity can be stored in the battery rather than immediately exported. The stored energy can then be used later when your home needs it.

Yes. Many battery systems can charge from the grid, which can be particularly useful with tariffs offering cheaper overnight or off-peak electricity for use later.

There's no one-size-fits-all answer. The right capacity depends on your electricity use, solar generation, usage patterns, tariff and what you want the battery to achieve. Bigger isn't automatically better.

kWh (kilowatt-hour) tells you how much energy a battery can store, but it's also important to consider its usable capacity.

For example, a 5.76 kWh battery with a 90% Depth of Discharge (DoD) would provide around 5.18 kWh of usable energy. 90% of 5.76 = 5.18. Exact usable capacity depends on the particular battery.

Yes. Battery storage can be retrofitted to many existing solar PV systems, although the existing equipment, metering and electrical installation should first be assessed to determine the most suitable solution.

Yes. Adding battery storage does not automatically mean losing your existing Feed-in Tariff (FIT) payments. Ofgem states that payments can continue provided the eligible solar generation — and export where applicable — can still be accurately measured.

An AC-coupled battery can often be a suitable retrofit solution because it can be installed separately from the existing solar generation equipment and metering. However, every FIT installation should be assessed individually, and your FIT provider should be informed of relevant changes to the installation.

Yes. The Smart Export Guarantee (SEG) pays eligible customers for electricity exported to the grid. Having battery storage does not prevent you from receiving export payments.

A suitable battery and electricity tariff may allow you to charge when electricity is cheaper and use the stored energy during more expensive periods.

It can reduce grid imports, but it won't eliminate them. If your battery is depleted or your electricity demand is greater than the system can supply, your home will import electricity from the grid as normal.

A battery system needs to be specifically designed and installed with suitable backup or EPS (Emergency Power Supply) equipment to provide electricity when the grid goes down.

Depending on the system design, backup can supply selected essential circuits or potentially a larger part of your home. If solar PV is also installed, some suitably designed systems can continue using solar generation to help power your home and recharge the battery during the outage.

Most modern home batteries use lithium-ion technology, with Lithium Iron Phosphate (LFP or LiFePO₄) now commonly used due to its long cycle life, stability and safety characteristics.

Newer technologies such as sodium-ion are also emerging and may become more common as battery technology develops.

Yes. All rechargeable batteries gradually lose some usable capacity as they age and are charged and discharged. Modern home batteries are designed for many years and thousands of cycles, with manufacturer warranties typically providing protection around their expected performance and remaining capacity.

Yes, but cold temperatures can affect battery charging and performance. Most modern batteries include built-in heating or thermal management to help keep them within a suitable operating temperature during colder weather.

It depends on the battery and property. Manufacturer requirements, temperature, environmental conditions, access and fire safety should all be considered when selecting a suitable location.

This depends on the battery and inverter. Batteries have a maximum charge and discharge power, which determines how quickly they can store energy and how much power they can provide to your home at once.

Yes. Many modern systems have an app or online monitoring platform where you can view battery levels and energy flows and, depending on the system, set charging schedules.

Yes, with a suitable system and tariff. Many customers choose to charge during cheaper overnight or off-peak periods, particularly during winter when solar generation is lower.

If you have solar PV and your battery is full, surplus solar electricity that your property isn't using will normally be exported to the electricity grid.

It depends on how much energy is stored in your battery and how much electricity your home is using.

For example, if you had 5 kWh of battery storage and your home was continuously using 1 kW, the battery could provide roughly 5 hours of power. If your home was using 2.5 kW, it would last roughly 2 hours.

The more power your home is using, the quicker the battery will empty.

Many modern battery systems are designed to allow additional battery capacity to be added later. Some simply stack or connect together almost like building blocks, while others may require an additional junction or connection box to connect the extra batteries.

The exact expansion options depend on the battery manufacturer, model and existing system.

Battery systems generally require little routine maintenance, but monitoring and periodic system health checks can help identify faults or performance issues.

Visit our Operations & Maintenance page to find out how we can help look after your existing renewable energy system.

A battery cycle is one full charge and discharge of the battery's usable capacity. For example, charging a battery to full and then using that stored energy would represent one full cycle.

Modern home batteries are designed for thousands of cycles over their lifetime, with cycle life being one of the ways battery lifespan and performance can be measured.