Best Solar Batteries for UK Homes in 2025: Evergy's Expert Picks

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 (LiFePO)

• 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 (LiFePO)

• 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.