Mana Solar

Residential Battery Storage (BESS)

Solar batteries, or solar power storage, allows you to store electricity generated from the sun through your solar panels, to then use in the evening, during a power outage or at a later date. Adding solar batteries is a great way to use more renewable energy,  utilising the power you generate yourself and decrease your reliance on the grid.

We offer solar batteries as part of our solar panel installation packages, or you can add solar batteries to an existing solar panel system.

Our team of solar and battery-storage experts will provide information and advice to help you choose the right power storage solution for your needs.

Adding solar battery storage

Solar panels generate the most power during daylight hours, which is often when homes use the least electricity. Whilst this unused electricity can be sold back to the grid, you could benefit more by storing it in a solar battery and using the energy to power your own home.

A solar battery package maximises your own use of the low-carbon energy you’re generating from the sun. This means you’ll import less electricity from the grid, saving you money on your energy bills.

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Solar panel batteries, also known as solar battery storage systems, work by storing the excess energy produced by solar panels (also referred to as solar PV panels) during the day. There are two main battery technologies currently used, lithium-ion and lead-acid, both of which are designed to handle the cyclic charging and discharging required for solar energy storage.

When sunlight hits a solar panel, the solar cells in the panel convert the sunlight into electrical energy in the form of direct current (DC). This DC electricity then flows to the inverter, which converts the DC into alternating current (AC) that can be used to power household appliances and devices. If the demand for electricity in your home is less than that being generated, then the DC can be taken from the solar panels and used to charge a battery.

During the night, when your home demands electricity your solar battery discharges to power your appliances and devices, so you’re reaping the benefits of solar PV long after the sun has set.

All batteries store the energy as DC, so they need some form of inverter to convert this to AC for use in the home.

Some systems, those using hybrid inverters (the same inverter for both PV and battery) are called “DC coupled”, or “DC connected”, as the battery is connected to the PV on the DC side of the inverter.

For more complicated or larger systems, or when there’s already PV in a property and you want to add a battery, you’ll need to have separate battery and PV inverters. In this case the battery is effectively joined to the PV system on the AC side of the inverters, these are called “AC connected” or “AC coupled” batteries.

There’s four types of solar battery: lead-acid, lithium-ion, flow batteries, and nickel cadmium. In the UK there are two types of solar batteries commonly available, these are lead-acid and lithium-ion batteries.

Lead acid batteries are usually cheaper than lithium-ion batteries, but not as efficient and have a shorter lifespan. Lithium-ion batteries, on the other hand, are more expensive but have a longer lifespan and are more efficient.

The typical wall space required for an inverter and battery system is just over one metre in width, and between 1.3m and 1.9m in height, depending on the power and size of the battery. You’ll need somewhere to house the battery and system, and they can be installed in most places such as a garage or utility room.

We’ll conduct a full survey of your home that’ll help you to decide on the best location for your battery. It has to be fairly close to your main consumer unit so we have to take that into account but we normally try to put it in a cupboard, garage, utility room or somewhere similar.

We advise against this for safety reasons.

You don’t need to have a battery for your solar PV panels to work. However, energy storage allows you to use more of the eco-friendly energy you generate in your home rather than exporting it back to the grid, which could save you money.

The average lifespan of a solar battery is around ten years, but this can vary depending on the type of battery, the usage, and the maintenance. Our battery systems come with a 10-year manufacturer’s warranty.

Yes, you can. If we can’t find anywhere to fit a battery inside, you can have your solar battery wall-mounted on the outside of your property. However, it shouldn’t be in view of direct midday sun, (i.e. not on a south-facing wall) or be exposed to direct rain, and some kind of roof/shelter will be required.

You should always check with your Feed-in Tariff (FiT) provider, but when we fit a battery-only system we don’t touch the existing solar system; we just fit an “AC-connected” battery system, which monitors the existing solar inverter, but doesn’t electrically interact with it. Using this technology, your existing FiT payments shouldn’t be affected.

After installing your battery, you may choose to change to a SEG export tariff instead of FiT export.

As of June 2023, only solar batteries fitted at the same time as solar panels qualify for the zero rate of VAT; batteries supplied as standalone installations are subject to the higher rate of VAT (20%).

Our battery systems have an “Emergency Power Supply” (EPS) capability, but connecting this up is unfortunately outside of our scope of supply, as it requires major electrical works to reconfigure your household electrics, and also requires provision of a separate earth (normally one or more earth rods need to be driven into the ground near your property).

You may find other qualified local electricians to complete this work for you after we’ve installed your solar panels.

Once EPS is installed and configured, then in the event of a power cut, your battery system can run in ‘island mode’, and it can supply energy from your battery into your property, and the battery can also be recharged from solar.

You can discuss this in detail with one of our experts before going ahead with any installation.

Two factors to consider are:

  • Do you have sufficient excess solar generation in order to charge the battery each day, across most of the year?
  • Do you have sufficient consumption to make use of a fully-charged battery every night?

I already have a solar battery installed, can I get more Battery storage?

If you have an existing battery system from another manufacturer then we can fit a full, new  system (AC-connected inverter and battery modules) to expand your storage capacity.

You can still talk to us about your options, though, if you have any questions.

“Depth of discharge”    is the proportion of the battery’s nominal capacity available to use e.g. a battery may have a nominal value of 5kWh but if the Depth of Discharge is 80% then the amount charge that can actually be used is only 4kWh. 

“Usable Capacity” – is the number of kilowatt-hours (kWh) of energy that a fully charged battery will provide before the battery management system stops any more charge being taken. This is measured as the number of kilowatt-hours to charge the battery so the amount of energy actually available for you to use in your home is typically about 95% of this value, because of small efficiency losses as the battery is charged and discharged.

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