Solar Panels and Battery Storage: The Complete Guide

Why Add Battery Storage to Solar?

Solar panels generate most electricity during the middle of the day when many households are at work. Without a battery, surplus generation is exported to the grid at 4-15p/kWh, while you buy electricity back at 24.5p/kWh in the evening. A battery captures that surplus for evening use, increasing self-consumption from 35-50% to 70-85%. This turns every stored kilowatt-hour into a 10-20p saving versus exporting and re-buying.

The financial case has strengthened further with time-of-use tariffs. Batteries paired with Octopus Agile or Flux enable arbitrage: importing electricity at 7p/kWh overnight and exporting at 26-30p/kWh during peak 4-7pm, generating approximately 19p/kWh profit per cycle. Typical annual tariff-optimisation savings reach £300-£600 on top of solar self-consumption gains.

Battery Costs and Brands in 2026

Fox ESS EVO (5-10kWh modular) is our most-installed battery range, running £3,800-£5,200 and offering LFP chemistry with a 10-year warranty, smart tariff integration, and a modular design that lets you expand capacity over time. The 9.6kWh model suits most 3-4 bedroom homes.

Tesla Powerwall 3 (13.5kWh) costs £7,000-£11,500 installed, offering 11kW continuous output and 97.5% DC efficiency with a built-in inverter — ideal for larger homes or where backup power is a priority. Pylontech Force-H2 (7.1-14.2kWh) costs £3,500-£5,000 with 8,000+ cycle life. BYD HVS/HVM (5.1-22.1kWh) offers 10,000+ cycles at £4,000-£8,000.

Sizing Your Battery for East Anglia

A 5kWh battery suits 1-2 bedroom homes with low evening consumption. A 9.5-10kWh battery matches most 3-4 bedroom family homes, capturing a full day's surplus solar from a 4-6kW system. A 13.5kWh+ battery suits larger homes, EV owners, or those wanting maximum self-sufficiency and tariff arbitrage capacity. We recommend sizing based on your evening electricity consumption (typically 8-15kWh for a family home) and solar system size.