Solar Battery Storage: the best options in 2025

Tired of high electricity bills? In 2025, solar energy emerges as a beacon of hope, offering an affordable and eco-friendly solution. However, the magic of solar power truly shines when paired with efficient battery storage, and the ultimate game-changer is Lithium Iron Phosphate, or LiFePO4, batteries. 

Your quest for the best solar storage solutions in 2025 should begin and end here, with LiFePO4 batteries leading the charge. Join us as we delve into why these batteries are the optimal choice for storing solar energy and explore how you can harness their power for a brighter, greener future. 

Why do I need a battery for my solar array?

When setting up a solar array (a grouping of solar panels), you'll need a reliable solar battery to store surplus energy captured from the sun. This is crucial because the power generated by your solar system isn’t always used immediately, a battery allows you to keep this extra energy ready for use whenever you need it. 

It's important to note that you don’t necessarily need a complete solar setup to benefit from a solar battery. You can purchase a standalone battery (and inverter) and charge it using grid power during cheaper, off-peak hours. 

Why is LiFePO4 the best battery chemistry for solar energy storage?

When it comes to solar energy storage, choosing the right battery chemistry is crucial. LiFePO4 (or Lithium Iron Phosphate) has emerged as the best option for solar battery storage.

Why? Let's break it down.

Longer Lifespan

LiFePO4 batteries have an impressive lifespan, lasting up to 15 years (or more!). This is due to their stable chemical structure which reduces the risk of degradation over time. In comparison, lead-acid batteries typically last only 2-3 years.

Safer Option

When it comes to safety in solar energy storage, LiFePO4 batteries are the standout option. Unlike some other battery types, they exhibit a significantly reduced likelihood of thermal runaway—a condition where overheating could lead to explosions. Additionally, LiFePO4 batteries are less prone to catching fire compared to other lithium-ion and lead-acid batteries, making them a more dependable choice.

Efficient Energy Storage

LiFePO4 batteries are highly efficient at storing solar energy. They have a higher depth of discharge, meaning that more of the energy stored in the battery can be used. 

Why do LiFePO4 batteries require less maintenance?

LiFePO4 batteries are well known for their low maintenance requirements due to their unique chemistry. Unlike other battery chemistries, LiFePO4 batteries have a much lower risk of overheating or catching fire. This means there is no need for extensive cooling systems or regular maintenance checks to prevent damage.

Additionally, LiFePO4 batteries have a longer lifespan compared to other battery types, which means they need to be replaced less frequently. This, in turn, reduces maintenance costs and effort on your part!

Overall, the unique chemistry of LiFePO4 batteries makes them the most reliable, low-maintenance option for storing solar energy.

How many batteries will I require for my Solar set-up?

The appropriate size of a solar battery needed in the UK can vary based on several considerations, including your household's electricity consumption and the dimensions of your solar panel setup.

Typically, a 5-15 kWh battery serves as an excellent starting point for domestic solar systems in the UK. Nevertheless, if your energy usage is high or you aim to achieve complete energy independence from the power grid, a more substantial battery might be necessary. 

Some important questions to ponder include:

- What amount of kWh your solar installation will generate?
- What does your overall energy consumption look like?
- How many days do you wish your backup batteries to sustain your home during grid outages or prolonged spells of minimal sunlight? 

To determine yur consumption, begin by identifying all the appliances and devices within your home, noting their wattage. Then, compute your daily energy consumption by multiplying each appliance's wattage by the number of hours it is typically used per day, resulting in the total usage in watt-hours (Wh) or kilowatt-hours (kWh). 

As a general guideline, anticipate receiving around 50% of your yearly solar energy between June and August, while only about 10% during December through February.

Exploring Battery Options: DIY Battery Builds

Fogstar is the leading retailer in the UK for enthusiasts aiming to construct their own DIY LiFePO4 batteries. We provide a wide selection of cells, BMS, and kits, offering numerous choices for creating a sustainable DIY solar battery solution. 

Seplos Mason DIY Kits 

The DIY Seplos Mason Kits offers a versatile solution for constructing your own 48V battery system, perfect for storing surplus solar energy in both off-grid and grid-tied setups. Starting from just £1,559.83, the SEPLOS V4 kits deliver substantial storage capacity at a remarkably low price.

Available capacities range from 14.3kWh to 16kWh, allowing you to tailor your energy storage to your unique requirements. You can choose between Grade A or Grade B prismatic cells based on your budget and preferences. 

With a modular design, you can easily expand your battery capacity by connecting up to 16 additional packs in parallel. This design also supports customisable LiFePO4 cell options, allowing you to select from renowned cell suppliers like EVE and Envision to build a battery pack up to 16kWh in size. 

The kit includes a sophisticated Smart BMS (V3 SEPLOS) equipped with Bluetooth, which integrates seamlessly with a variety of inverters (including Victron, Growatt, Sofar, Solis) using CAN and RS485 communication. These kits also offer a reliable 250A DC Breaker, LCD Colour Screen and Active Balancing.

LiFePO4 Cells and BMS 

If you're not keen on a modular kit design, choosing LiFePO4 cells combined with a Battery Management System (BMS) can help reduce costs. EVE and Envision are among the top choices available, offering Grade A and Grade B options, with prices beginning at only £59.99 per cell. 

To ensure your cells perform optimally, pairing them with a reliable Battery Management System (BMS) is essential. Brands like JBD, JK, and Seplos provide excellent options for cell management and safety. For those looking to have their BMS directly integrate with their inverter, it’s advisable to select a BMS with integrated protocols. A perfect example is the Seplos V3 BMS, which is an excellent choice.

Exploring Battery Options: Racks and 16.1kWh Units

5.12kWh Fogstar Energy Rack Batteries

At just £205.07 per kWh, our UK designed Server Rack Battery comes complete with 16 Grade A EVE LiFePO4 Cells, heating, several pre-loaded inverter protocols, TFT LCD touch screen, a DC Rated Breaker,, an 8 year warranty and full UK-based support.

We've even designed Fogstar Rack Cabinets in either a 15kWh or 30kWh capacity to safely house the batteries indoors.  We also offer a IP56 Rated Outdoor battery system featuring the 5.12kWh Rack Batteries, these are available in 20.48kWh and 40.96kWh in size. You can also build out your outdoor configuration over time by adding more 5.12kWh batteries as your energy needs evolve. Connect up to 32 (31 with Victron) batteries together for a maximum potential capacity of 163.84 kWh - across 4 outdoor cabinets. 

The ease of use and integration with a wide range of inverters, along with the plethora of additional features, has made them a popular choice with homeowners and commercial customers alike. You can read more about our rack batteries over at our previous blog.

Fogstar Energy 16.1kWh Battery 

The Fogstar Energy 16.1kWh Battery delivers exceptional value for money, being the most affordable battery of its capacity in the world, while its weight reflects its superior construction and durability. At a cost per kWh of just £161.49, this battery repaints the narrative for solar battery storage in the UK market.

Featuring an intelligent heating system, it ensures reliable operation even in extreme temperatures as low as -20°C. The PACE Battery Management System (BMS) allows seamless plug-and-play compatibility with popular inverters such as Victron, Growatt, and Solis, while its 4.3-inch LCD touchscreen makes monitoring and protocol adjustments effortless. Built with premium Grade A EVE LiFePO4 cells, the battery boasts an impressive 8,000-cycle lifespan, an 8-year warranty, and active balancing technology for optimal efficiency. Safety is also a priority, with a 250A DC breaker preventing potential faults.

Recognised as the 'Best for High-Usage Households' by the London Evening Standard, this battery is an excellent investment for those seeking reliable, high-capacity, and future-proof energy storage.

Do I pick my battery or Inverter first? 

Your inverter dictates which battery types, voltages, and communication standards can be used. Choosing the inverter first ensures smooth integration with your selected battery. 

The choice of inverter depends on your energy goals, whether you're planning to be on-grid, fully off-grid, or hybrid. Knowing this helps in selecting a battery with adequate capacity and the potential to scale up. 

If you're considering a specific battery like the Fogstar Energy 16.1kWh, it's crucial to ensure that your inverter is compatible with the battery's voltage and communication protocols. For enhanced flexibility, opt for batteries known for their wide inverter compatibility. The Fogstar 48V battery range, for instance, can seamlessly integrate with brands like Victron, Growatt, Solis, and many others.

Who can install my solar battery?

Many homeowners with existing solar setups who are adding battery storage choose to install the battery themselves, provided they feel sufficiently skilled. However, should any assistance be needed, professional help is readily available all across the UK.

At Fogstar, we collaborate with a diverse network of expert installers to ensure your solar battery system is set up for optimal performance. You can explore our Installer Locator to find a professional near you. Before choosing an installer, it's crucial to: 

• Verify MCS Certification: Ensure that your installer is MCS certified, assuring high standards in renewable technology installations.
• Review Customer Feedback: Check out reviews from previous clients to gain insights into the installer's reliability and quality of service.
• Compare Multiple Quotes: Obtain detailed quotes from various installers to find the best value and service that meets your budget and needs.

The Bright Future of Solar Energy Storage

Battery innovators like Fogstar have set the standard with cost-effective options that promise to revolutionise how we store solar energy. The Fogstar Energy 16.1kWh Battery System, with its remarkably low cost per kWh, positions itself as an ideal choice for homeowners seeking high value and superb quality. Meanwhile, Seplos DIY Kits provide the versatility for those who aspire to construct their own solar battery systems, allowing greater personal involvement and cost efficiency. 

As technology evolves and prices possibly become more favourable, the idea of a future driven by clean, self-sustaining energy grows more achievable.