About This Service
Get more from the solar you already have
If your solar system was installed without battery storage — which was the majority of installations before 2018 — there is a strong financial case for adding storage now. Battery prices have fallen significantly and the gap between export rates (what you receive for surplus) and import rates (what you pay to buy electricity back) is wider than ever.
A typical 10kWh battery retrofit on a 4kW solar system can increase self-consumption from 35% to 75–80%, saving an additional £400–600 per year at current energy prices — on top of what you're already saving with solar.
AC coupling vs DC coupling
AC-coupled batteries connect to your home's AC supply, independent of the solar inverter. They charge from solar generation that would otherwise be exported, and they can also charge from the grid. AC coupling works with almost any existing solar inverter and is the standard approach for retrofits. DC-coupled batteries connect directly to the solar panels' DC circuit, bypassing the existing inverter — this is more efficient but requires either replacing the existing inverter or a hybrid inverter with DC input capability. We'll assess your existing system and advise which approach is optimal.
Optimising your existing inverter
Some existing inverters — particularly SolarEdge, SMA and Fronius units — have built-in battery readiness features that can be unlocked with a retrofit. In these cases, a compatible battery can integrate with your existing monitoring app and provide a more seamless experience. We'll identify whether your inverter supports this before recommending a standalone AC-coupled system.
We retrofit to systems we haven't installed
We regularly retrofit battery storage to systems installed by other companies — including firms that are no longer trading. We work from your existing installation certificate and documentation, and update your registration on completion of the retrofit. If documentation is missing or incomplete, we'll advise on the most appropriate route to certification.
Export limitation and DNO requirements
Adding battery storage to an existing solar system may require notification to your DNO — particularly if total generation capacity (solar + battery export) could exceed the original G98/G99 notification threshold. We handle all DNO correspondence as part of the retrofit installation.