Evergy’s Top Solar Battery Picks for 2025
Choosing the right solar battery isn’t just about picking the biggest unit or the cheapest option. The right solution depends on your energy usage, roof size, tariff, and whether you want backup power, modularity, or just the most cost-effective way to reduce your electricity bill.
At Evergy, we only stock systems we trust to perform long-term with warranties to match. Below, we’ve selected four of the best solar batteries available in the UK for 2025, all of which are:
Lithium iron phosphate (LFP) based for safety and longevity
Compatible with Evergy’s range of inverters and hybrid systems
Backed by 10-year warranties and local UK support
Suitable for both new solar installs and retrofits
We’ll break down each product in terms of:
Usable storage capacity (kWh)
System type (modular vs fixed)
Smart tariff compatibility
Ideal property type
Approximate price band
These batteries are used in real homes across the UK from urban terraces to countryside off-grid setups and each one is supported by our installer network and Evergy’s post-sale support team.
Myenergi Libbi (5kWh–20kWh Modular Battery System)
The Myenergi Libbi is one of the most flexible and future-ready solar batteries available in the UK and it’s designed specifically for homes that want intelligent energy control, modular scaling, and full integration with other Myenergi products like the Zappi EV charger and Eddi diverter.
Unlike most battery systems that come in fixed capacities, the Libbi is modular meaning you can start with a single 5kWh unit and expand all the way up to 20kWh, depending on your home’s needs. Each unit is slim, compact, and stackable, making it a strong choice even in space-restricted properties.
Key Specs and Features
Capacity: 5kWh per unit (up to 4 units for 20kWh total)
Battery type: Lithium iron phosphate (LFP) – safe and long-lasting
Compatible inverter: Myenergi Libbi hybrid inverter (included in system bundles)
Installation: Wall-mounted or stacked floor mount
Warranty: 10 years
Why We Recommend It
Modular and scalable – Ideal if you want to start small and add more capacity over time.
Built for the UK – Designed in Britain, optimised for UK homes and regulations.
Smart energy control – Monitor, schedule and optimise your battery via the Myenergi app, and seamlessly link with Zappi and Eddi.
Grid and solar charging – Charge from your panels or the grid at off-peak times (perfect for Octopus Intelligent or Flux tariffs).
Backup power support – Optional backup kit available to supply circuits during outages.
Best For:
Homeowners planning a solar + EV charger system
Those on variable tariffs wanting automated optimisation
Properties with changing energy needs like growing families or future electrification
🔗 Explore the Myenergi Libbi 5kWh Modular Battery Pack (B05H)
📞 Need help choosing your capacity? Contact Evergy’s team for guidance.
SolaX Triple Power HV 5.8kWh LFP Master Battery V2
The SolaX Triple Power HV 5.8kWh LFP Master Battery V2 is a high-voltage lithium iron phosphate (LFP) battery designed for homeowners seeking a scalable and efficient energy storage solution. This battery serves as the foundation of the SolaX Triple Power system, allowing for expansion with additional slave batteries to meet varying energy demands.
Key Specifications:
Nominal Capacity: 5.8 kWh
Usable Capacity: 5.1 kWh
Battery Type: Lithium Iron Phosphate (LFP)
Nominal Voltage: 115.2 V
Operating Voltage Range: 100 – 131 V
Depth of Discharge (DoD): 90%
Cycle Life: Over 6000 cycles
Maximum Charge/Discharge Power: 4.0 kW
Round-Trip Efficiency: 95%
Ingress Protection Rating: IP65
Dimensions: 474 mm (L) × 193 mm (W) × 708 mm (H)
Weight: 72.2 kg
Warranty: 10 years
Scalability and Compatibility:
The SolaX Triple Power system is designed with scalability in mind. Starting with this master battery, homeowners can connect up to three additional 5.8 kWh slave batteries, achieving a total capacity of up to 23.2 kWh. This flexibility allows for tailored energy storage solutions based on individual household needs.
The battery is compatible with SolaX's range of hybrid inverters, including the X1-Hybrid and X3-Hybrid series, facilitating seamless integration into existing solar PV systems.
Installation and Design:
With an IP65 rating, the battery is suitable for both indoor and outdoor installations, offering protection against dust and water ingress. Its compact design allows for floor or wall mounting, providing installation flexibility to suit various property layouts.
Safety and Longevity:
utilising LFP chemistry, the battery ensures enhanced safety, thermal stability, and a longer lifespan compared to other lithium-ion batteries. The high cycle life of over 6000 cycles guarantees long-term performance and reliability.
Why Choose the SolaX Triple Power HV 5.8kWh Master Battery V2:
Modular Design: Expandable storage capacity to match growing energy needs.
High Efficiency: 95% round-trip efficiency ensures minimal energy loss.
Robust Warranty: 10-year warranty provides peace of mind.
Versatile Installation: Suitable for various environments and mounting options.
Enhanced Safety: LFP technology offers superior safety and longevity.
For more information or to purchase, please visit Evergy's product page: SolaX Triple Power HV 5.8kWh LFP Master Battery V2
Sunsynk 5.32kWh Battery (IP20 & IP65 Models)
The Sunsynk 5.32kWh Battery offers a reliable and scalable energy storage solution for UK homeowners seeking to enhance their solar PV systems. Available in both IP20 and IP65 models, this battery caters to various installation environments, from indoor utility rooms to outdoor settings.
Key Specs and Features
Usable Capacity: 4.79 kWh
Battery Type: Lithium Iron Phosphate (LiFePO₄)
Nominal Voltage: 51.2 V
Depth of Discharge (DoD): 90%
Cycle Life: Over 6,000 cycles
Scalability: Up to 32 units in parallel (totaling 170 kWh)
Communication Ports: RS485, CAN
Warranty: 10 years with Sunsynk inverter; 5 years standalone
Why We Recommend It
Versatile Installation Options:
IP20 Model: Ideal for indoor installations, such as utility rooms or garages.
IP65 Model: Suitable for outdoor installations, offering protection against dust and water ingress.
High Scalability: Easily expand your storage capacity by connecting multiple units in parallel, accommodating growing energy needs.
Efficient Performance: With a 90% DoD and high cycle life, the battery ensures long-term reliability and optimal energy utilisation.
Seamless Integration: Designed to work harmoniously with Sunsynk's range of hybrid inverters, facilitating efficient energy management.
Best For:
Homeowners seeking a cost-effective and scalable energy storage solution.
Properties requiring flexible installation options, both indoors and outdoors.
Users aiming to maximise solar energy usage and reduce reliance on the grid.
🔗 Explore the Sunsynk 5.32kWh Battery IP20
🔗 Explore the Sunsynk 5.32kWh Battery IP65
Fox ESS Energy Cube ECM2900 2.88kWh HV Battery (Master)
The Fox ESS Energy Cube ECM2900 is a high-voltage, modular battery system designed for homeowners seeking a scalable and efficient energy storage solution. As the master unit in the Energy Cube series, it provides the foundational control and initial 2.88kWh capacity, allowing for seamless expansion with additional slave modules to meet growing energy demands.
Key Specs and Features
Usable Capacity: 2.88kWh
Battery Type: Lithium Iron Phosphate (LiFePO₄)
Scalability: Expandable up to 20.16kWh with six additional slave units
Depth of Discharge (DoD): 90%
Cycle Life: Over 6,000 cycles
Operating Voltage: 115.2V (with one slave unit)
Communication Interfaces: CAN/RS485
Installation: Stackable, plug-and-play design
Ingress Protection Rating: IP65 (suitable for indoor and outdoor installations)
Warranty: 10 years (upon registration with Fox ESS)
Why We Recommend It
Modular Design: Start with a single master unit and expand your storage capacity by adding up to six slave modules, achieving a total capacity of 20.16kWh.
Efficient Performance: With a 90% depth of discharge and high cycle life, the ECM2900 ensures long-term reliability and optimal energy utilisation.
Flexible Installation: Its compact, stackable design and IP65 rating allow for versatile installation options, both indoors and outdoors.
Seamless Integration: Designed to work harmoniously with Fox ESS hybrid inverters, facilitating efficient energy management and monitoring.
Best For:
Homeowners planning to start small and scale up their energy storage over time.
Properties requiring flexible installation options, accommodating both indoor and outdoor environments.
Users aiming to maximise solar energy usage and reduce reliance on the grid.
🔗 Explore the Fox ESS Energy Cube ECM2900 2.88kWh HV Battery (Master)
Solar Battery Comparison Table (2025)
Choosing the right battery often comes down to key specs: usable capacity, lifespan, cost, and compatibility. Below is a side-by-side comparison of the four systems Evergy recommends for UK homes in 2025.
| Brand & Model | Usable Capacity | Expandable To | Chemistry | Warranty |
| Myenergi Libbi | 5–20kWh | 20kWh | LFP | 10 years |
| SolaX Triple Power HV | 5.1kWh | 23.2kWh | LFP | 10 years |
| Sunsynk 5.32kWh IP20/IP65 | 4.79kWh | 170kWh | LFP | 10 years |
| Fox ESS ECM2900 | 2.88kWh | 20.16kWh | LFP | 10 years |
How Much Do Solar Batteries Cost in 2025?
The cost of a solar battery in the UK can vary significantly depending on its size, chemistry, brand, and whether it’s installed alongside a new solar PV system or retrofitted later.
At Evergy, most domestic battery setups range between £2,000 and £9,000, with optional add-ons for backup kits or advanced inverters. Here's what to expect for a typical setup in 2025:
| System Size | Battery Example | Typical Installed Cost (inc. VAT) | Includes |
|---|---|---|---|
| Small (2.5–5kWh) | Fox ESS ECM2900 | £2,000 – £3,500 | Battery + basic install |
| Medium (5–10kWh) | Sunsynk 5.32kWh IP65 or SolaX HV | £3,500 – £5,500 | Battery + inverter |
| Large (10–20kWh) | Myenergi Libbi (stacked) | £6,000 – £9,000 | Battery stack + inverter |
Smart Tariffs and Solar Battery ROI
A solar battery doesn’t just let you use more of your solar energy it can also help you actively profit from the UK’s growing list of time-of-use energy tariffs. These tariffs reward households for shifting their energy use to cheaper times of day, or even for exporting electricity back to the grid during peak hours.
How Smart Tariffs Work with Batteries
When paired with a smart tariff, your battery can:
Charge from the grid overnight at ultra-low rates (e.g. 7.5p/kWh)
Discharge during peak hours when electricity prices hit 30–40p/kWh
Store excess solar energy during the day, avoiding costly imports later
Export electricity back to the grid when prices are high (SEG & Octopus Flux)
Popular Smart Tariffs in the UK (2025)
| Tariff | Rate Type | Example Rate (2025) |
|---|---|---|
| Octopus Flux | Dynamic import/export | 7p–34p/kWh |
| Octopus Agile | Half-hourly pricing | 2p–40p/kWh |
| OVO Drive Anytime | Fixed EV rate | 10p/kWh |
Which Solar Battery Is Best for You?
With so many excellent options available, the best solar battery for your home depends on a few key factors including how much electricity you use, whether you already have solar panels, and how flexible you want your system to be in future.
🔍 For Small to Medium Homes (2–3 bedrooms)
You likely use moderate electricity and want to maximise solar use without overinvesting.
Recommended:
Sunsynk 5.32kWh IP20
These options are compact, cost-effective, and scalable if your needs grow.
🚗 For Homes with EV Charging
If you have an EV and are on a smart tariff, pairing your solar with battery storage can dramatically cut charging costs.
Recommended:
Myenergi Libbi fully compatible with Zappi chargers
SolaX Triple Power HV excellent for hybrid solar + EV systems
🏡 For Large Homes or Future Expansion
Larger homes with high usage, or those installing a system they want to grow into, will benefit from scalable setups with higher total capacity.
Recommended:
Sunsynk 5.32kWh IP65 tough, weatherproof, expandable
📎 Still deciding? Start by reading our guide on whether solar panels are worth it in the UK especially if you’re new to solar.
Get Expert Help Choosing Your Solar Battery
Whether you’re looking to cut energy bills, power your home through outages, or make the most of a time-of-use tariff, the right solar battery can make all the difference. But choosing the best one depends on more than just kWh and price it’s about compatibility, lifestyle, and long-term goals.
At Evergy, we don’t just sell batteries we help you build smarter, more resilient home energy systems. Our team can:
Recommend the ideal setup based on your usage, property, and future plans
Arrange installations through our trusted installer network
Provide bundled solutions with inverters, EV chargers, and solar panels
🔗 Ready to find the right battery for your home?
Contact the Evergy team today or browse our full solar battery range online.
Solar Battery FAQs – What UK Homeowners Want to Know
Are solar batteries worth it in the UK in 2025?
Yes especially if you already have solar panels or plan to install them. A battery allows you to use more of your own generated electricity, reducing reliance on the grid and cutting bills further. With smart tariffs like Octopus Flux, you can even charge low and sell high, making payback faster than ever.
📎 See: Are solar panels worth it in 2025?
How long do solar batteries last?
Most lithium iron phosphate (LFP) batteries last over 10 years, with a typical cycle life of 6,000+ charges. This translates to roughly 15 years of daily use. All Evergy-recommended batteries come with 10-year manufacturer warranties when installed and registered correctly.
Do I need a battery if I already have solar panels?
Not necessarily your panels will still generate power during the day. But without a battery, any excess electricity goes back to the grid. A battery lets you keep that energy and use it when you need it most, like in the evening or overnight.
📎 Read our solar system setup guide
Can I add a battery later if I already have solar?
Yes all the batteries listed in this guide can be added to existing solar panel systems, either directly or via a compatible hybrid inverter. Just note that standalone battery installs may not qualify for 0% VAT, unlike systems installed with new solar panels.
📎 Explore solar panel grants and VAT info here
Can I still get a government grant for a battery?
There is no standalone battery grant in 2025, but if you’re installing a battery alongside solar panels, it qualifies for 0% VAT. Some regional or local schemes may offer additional funding, especially for energy efficiency upgrades.
Future-Ready Homes Run on Solar and Storage
Solar panels might power your home but batteries power your freedom. With the right system in place, you’re not just saving money; you’re shifting control of your energy usage back to you.
From modular stacks like the Myenergi Libbi to weatherproof power from Sunsynk and Fox ESS, there’s never been a better time to install solar storage in the UK. If you want to take advantage of smart tariffs, 0% VAT incentives, or just build a home that works smarter Evergy can help you make it happen.
🔗 Compare solar batteries on Evergy or speak to our team to design your system today.
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