How it fits together
How solar panels and a home battery work as one system
Panels make direct current. An inverter turns it into the alternating current your house uses. With a battery in the system, the inverter makes one decision every few seconds: use it, store it, or export it.
- Daytime. The house uses solar first. Anything left over charges the battery.
- Battery full. Only then does surplus go to the grid, where the Smart Export Guarantee pays for it.
- Evening. The battery runs the house until it reaches its reserve, then the grid takes over.
- Winter nights. Panels in the North East make little from November to January, so the battery earns its keep by charging from a cheap overnight rate instead.
Hybrid or AC coupled. On a new system we fit a hybrid inverter that handles panels and battery together. On a retrofit, an AC coupled battery has its own inverter and sits alongside your existing one, which leaves the original installation and its paperwork as they are.
Brands. We fit Fox ESS, SolaX, Alpha ESS and SolarEdge, all using lithium iron phosphate batteries, with tier 1 monocrystalline panels carrying a 25 year performance warranty. SolarEdge, with an optimiser behind each panel, is our choice where a chimney or a neighbour's tree shades part of the roof. Battery warranties are typically 10 years, depending on the brand.