How do I connect a battery to my solar system?

Connecting a Battery to Your Solar System — What Homeowners Need to Know Adding a battery to your solar setup lets you store surplus energy generated during the day and use it in the evening or during a power cut. However, the connection process involves high-voltage DC circuits that can be extremely dangerous if handled incorrectly. How a Solar Battery System Works Your solar panels generate DC electricity, which an inverter converts to AC for home use. A battery stores excess DC energy. Depending on your setup: AC-coupled systems — the battery connects on the AC side via its own inverter (e.g. a Powerwall or SolarEdge Energy Bank) DC-coupled systems — the battery connects directly to the solar charge controller or hybrid inverter on the DC side What You Can Safely Check Yourself Read your inverter's manual — confirm it supports battery storage and note the required battery voltage range (commonly 48V for most home systems) Check compatibility — not all inverters accept batteries; you may need a hybrid inverter upgrade Confirm your battery type — lithium (LiFePO4 is most common), lead-acid, or gel all have different wiring requirements Check your consumer unit space — a battery system may require a new dedicated circuit and MCB What You Should NOT Do Do not attempt DC wiring yourself unless you are a qualified electrician — solar DC circuits can carry lethal voltages even when panels are disconnected Do not connect a battery without a correctly rated fuse or DC breaker Do not use undersized cables — battery connections can carry very high currents (often 100A+) When to Call an Electrician Always call a Part P registered electrician or an MCS-certified installer to carry out battery connection work. They will: Install correct DC isolators and fuses Size and install appropriate DC cabling Configure the battery management system (BMS) Issue a Minor Works or Installation Certificate Notify Building Control if required This work may also affect your G98/G99 grid connection agreement — your installer should notify your DNO if system capacity changes significantly.