Best Modular Battery Storage (2026)

We rank modular battery storage on the specs that matter, value for money and reliability. Here's where we'd put our money this year.

PowerGuide is reader-supported. We may earn a commission from links on this page — it never affects our rankings or what we recommend.

BYD

2.56kWh modules

A widely-installed modular high-voltage battery that stacks from 5.1kWh to ~22kWh, paired with a third-party hybrid inverter.

4.3 ~£4,500

Fox ESS

ECS2900

Stackable high-voltage battery modules letting you size storage from ~2.9kWh up to ~16kWh.

4.2 ~£1,850

SolaX Power

5.8kWh modules

High-voltage modular battery that stacks to ~46kWh and integrates tightly with SolaX hybrid inverters for a single-vendor system.

4.2 ~£3,500

Pylontech

US5000

Popular 4.8kWh LFP module designed to stack (up to ~16 units) for low-voltage hybrid inverter systems.

4.1 £1,150