First ChoiceSolar

Hardware Architecture

The AC-Coupled Revolution: Integrating Storage into Legacy Solar.

James Hayward · Senior Technical Adviser, First Choice SolarPublished May 2026Last reviewed May 2026 3 min read G99 Grid Compliant · DNO Notification Handled by First Choice Solar

Executive Summary

Yes, you can add a high-capacity battery to any existing solar panel system, regardless of the original installer or the age of the panels. First Choice Solar utilises AC-coupled inverter technology — specifically the Fox ESS AC1(G2) — which seamlessly interfaces with your legacy hardware to capture surplus energy without requiring you to replace your existing panels or void your current warranties.

Stopping the Energy Leak

If you installed solar panels years ago without a battery, you are experiencing significant energy waste. Every kilowatt your home does not use immediately is exported back into the national grid — often for a minimal tariff rate. Retrofitting a smart battery captures that surplus generation for use overnight, dramatically improving your self-consumption rate and reducing your grid dependency.

The AC-Coupled Advantage

You do not need to replace your existing system. First Choice Solar engineers deploy specialised AC-coupled inverters designed to run in parallel with your existing setup. The Fox ESS AC1(G2) is specifically engineered for this purpose — compatible with any existing solar installation regardless of brand. Whether we integrate a modular Fox ESS EP battery stack or a premium Tesla Powerwall 3, the new intelligence layer intercepts your surplus AC power, stores it safely, and deploys it when the sun goes down.

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Technical Accuracy Pledge

Every figure in this article is sourced from manufacturer datasheets and independently verifiable accreditation registers. Last reviewed: May 2026.

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