Can I add a battery to existing solar panels?

Yes, in most cases. We need to check your existing inverter — if it is a hybrid inverter, connection is straightforward. If it is a standard string inverter, we may need to add a separate battery inverter or AC-coupled battery. We assess this during a free site visit.

How long do batteries last?

Most lithium-ion home batteries are warrantied for 10 years or 6,000–10,000 cycles, whichever comes first. At one cycle per day, that is 16–27 years. Real-world capacity degrades gradually — expect 80% of original capacity after 10 years.

Where is the battery installed?

Typically in a garage, utility room, or externally on a wall. Batteries are IP-rated for outdoor installation but need protection from direct rain and extreme temperatures. We will recommend the optimal location during your survey.

Battery Storage: Do You Need It With Solar Panels?

One of the most common questions we hear from Suffolk homeowners is whether battery storage is worth adding to a solar PV system. The answer depends on your energy habits, your electricity tariff, and how you feel about energy independence.

How Battery Storage Works

During daylight hours, your solar panels generate DC electricity. Your inverter converts this to AC for immediate home use. Any surplus is either exported to the grid for SEG payments or diverted into a lithium-ion battery. In the evening, when solar generation drops, the battery discharges to power your home — reducing or eliminating your need to buy electricity from your supplier.

Self-Consumption: The Key Metric

Without a battery, a typical Suffolk home uses only 30–40% of the solar energy it generates. The rest is exported. A 5kWh battery raises self-consumption to 70–80%. A 10kWh battery pushes it above 90%. The higher your self-consumption, the faster your payback.

Typical Battery Costs in 2025

A quality 5kWh battery unit (Tesla Powerwall 3, GivEnergy Gen 3, or Fox ESS) costs £2,500–£4,000 installed. A 10kWh system is £4,500–£6,500. When installed alongside a new solar system, the combined installation reduces labour costs and scaffolding hire, saving £300–£500 versus retrofitting a battery later.

Return on Investment

At 34p/kWh, every kWh stored and used instead of exported saves you roughly 20p (the difference between buying and SEG export rates). A 5kWh battery cycling once daily saves £365 per year. With a £3,500 installed cost, payback is 9.5 years — within the 10-year warranty. A 10kWh system saving £650/year pays back in 8.5 years.

Backup Power Mode

Some battery systems offer EPS (Emergency Power Supply) functionality, providing limited backup during power cuts. In rural Suffolk, where overhead lines can be vulnerable to storms, this is genuinely valuable. Not all inverters support EPS — we will specify this if it matters to you. Note that EPS usually requires a dedicated backup circuit, not your entire house.

Cheaper Overnight Charging

Even without solar, a battery can save money on time-of-use tariffs like Octopus Agile or E.ON's Fix and Drive. You charge the battery overnight at 7–10p/kWh and discharge during peak hours at 34p/kWh. This "arbitrage" can save £200–£400 per year depending on your tariff and usage pattern.

When Battery Storage Makes Sense

We recommend battery storage if: (1) you are installing solar and plan to stay in your home 8+ years; (2) you work from home and use significant electricity during daylight; (3) you have high evening usage (electric heating, EV charging, cooking); or (4) you live in a rural area where power cuts are a concern. If you are rarely home during the day and have low evening usage, the case is weaker.