Adding a battery to your existing solar in Scotland
Can I add a battery to my existing solar panels in Scotland?
Quick answer: A battery retrofit adds storage to your existing solar system. Three paths are possible: AC-coupling (Tesla Powerwall 3 connects alongside your existing inverter), hybrid inverter swap (replace your old inverter with a hybrid unit), or straight add-on (wire a Pylontech US5000 to your existing hybrid inverter). Battery storage with retrofit solar qualifies for 0% VAT until March 2027.
Key facts
- Three paths: AC-coupled, hybrid inverter swap, straight add-on
- 10kWh battery from ~£4,900–£5,100 installed (new inverter: £6,000–£8,000+)
- 0% VAT on battery storage with solar until 31 March 2027
- DNO notification required (G98 or G99 for systems over 3.68kW)
- Brands assessed: Tesla Powerwall 3, Duracell Dura5, Pylontech US5000
- Finance: Interest-free credit up to £30,000, subject to status
Last updated: 28 October 2026
A battery retrofit means adding storage to a solar system that is already on your roof. The cost, complexity and compatibility depend on your inverter type, system age and wiring. This page explains the three paths, what they cost, and which battery brands we assess.
The three retrofit paths
Your existing inverter determines which retrofit path applies. The compatibility checker identifies this from a few questions — no site visit needed for the initial assessment.
- AC-coupled (Tesla Powerwall 3): The battery has its own inverter and connects on the AC side. Your existing solar inverter is not touched. Typical install: one day. This is the go-to route for older string-inverter systems.
- Hybrid inverter swap (Duracell Dura5 or equivalent): Your old string inverter is replaced with a hybrid unit managing both solar and battery. More efficient (DC-to-DC, no conversion loss) but the install takes longer — typically two days.
- Straight add-on (Pylontech US5000): If you already have a compatible hybrid inverter, a battery can be wired directly to it. Usually the most affordable route. Typical install: one day.
Cost ranges
A 10kWh retrofit battery on existing solar typically costs ~£4,900–£5,100 installed. If a new inverter is needed, expect £6,000–£8,000+. A 5kWh battery starts at ~£3,500–£4,500 (source: homeenergyquotes.co.uk, Aug 2026; checked October 2026). A no-obligation survey gives you an exact price — these ranges are illustrative only.
Battery storage installed with retrofit solar qualifies for 0% VAT until 31 March 2027 in the UK (legislation.gov.uk/uksi/2024/24). After that date, the rate may revert to 5% or 20% depending on government policy at the time. Standalone batteries may also qualify for 0% VAT — we confirm this during your survey.
Want to compare options? See our guide to compare the top 20 home batteries in Scotland at batterystoragescotland.co.uk/compare-home-batteries/ or try the battery savings calculator at batterystoragescotland.co.uk/battery-savings-calculator/.
Interest-free credit up to £30,000, subject to status.
For a wider view on home battery storage, Battery Arbitrage (batteryarbitrage.co.uk) covers buying guides and tariff arbitrage strategies. To understand solar installation costs and export payments, Solar Cost Scotland (solarcostscotland.com) breaks down costs and savings. And if spreading the cost is what you need, Heat Pump Finance Scotland (heatpumpfinancescotland.co.uk) covers paying monthly with interest-free credit. Part of the Scottish Energy Efficiency network.
DNO notification and approval
Every battery retrofit requires DNO notification. Batteries over 3.68kW per phase need G99 prior approval before installation begins — typically 4 to 8 weeks. Smaller systems use G98 notification within 28 days of install. SP Energy Networks handles central and southern Scotland; SSEN handles the north, Highlands and Islands. Your installer handles this paperwork — we do it as part of the process.
Battery brands we assess
We assess compatibility for the Tesla Powerwall 3, Duracell Dura5 and Pylontech US5000. These are well-supported in the UK with strong warranties and proven track records.
The Tesla Powerwall 3 is AC-coupled, meaning it has its own built-in inverter and works with almost any existing solar system. The Duracell Dura5 is typically used with a hybrid inverter swap, connecting on the DC side for maximum efficiency. The Pylontech US5000 is a modular battery that wires directly to a compatible hybrid inverter, making it the go-to for straight add-on retrofits.
Sizing a battery for a Scottish home
The right battery capacity depends on your daily electricity usage, your solar generation, and your tariff. A 10kWh battery is a common choice for a 4kWp solar system in Scotland because it can store most of a summer day's surplus while still being useful for off-peak charging in winter. A 5kWh battery is suitable for smaller systems or homes with lower consumption. The survey models your expected generation and consumption to recommend the right capacity — too small and you still export surplus; too large and you pay for capacity you rarely fill.
Frequently asked questions
Will a battery work with my existing solar system?
Almost certainly — but the route depends on your inverter type and system age. String inverters from before 2018 typically need AC-coupling or a hybrid swap. Existing hybrid inverters may accept a straight add-on. Microinverter systems use AC-coupling. Our compatibility checker tells you which path applies to your setup.
How much does a battery retrofit cost in Scotland?
A 10kWh retrofit battery on existing solar typically costs ~£4,900–£5,100 installed. If a new inverter is needed, expect £6,000–£8,000+. A 5kWh battery starts at ~£3,500–£4,500 (homeenergyquotes.co.uk, Aug 2026; checked October 2026). A no-obligation survey gives you an exact price.
Do I need DNO approval for a battery?
Yes. Batteries over 3.68kW require G99 prior approval from your DNO (SP Energy Networks in central and southern Scotland; SSEN in the north, Highlands and Islands). Smaller systems use G98 notification within 28 days of install. Your installer handles this paperwork — we do it as part of the process.
Is a battery worth it without solar?
A battery can still save money on a time-of-use tariff by charging off-peak and discharging at peak rates. However, the savings are higher when paired with solar because you are storing your own generation rather than bought electricity. We assess both scenarios during your survey.
Which battery brands do you recommend?
We assess compatibility for the Tesla Powerwall 3, Duracell Dura5 and Pylontech US5000. These are well-supported in the UK with strong warranties and proven track records.
How long does a battery retrofit take to install?
Most battery retrofits take one to two days. AC-coupled installs are typically one day because the existing solar system is not disturbed. Hybrid inverter swaps may take two days because the old inverter needs decommissioning and the new one needs commissioning.
Is finance available for battery storage?
Interest-free credit up to £30,000, subject to status.
How do I get a quote?
Call us on 0141 230 0198 or complete the quote form on our Get a Quote page. We assess your existing solar system, arrange a no-obligation survey if compatible, and provide a written quote with an exact price.
Related guides
Last updated: 28 October 2026
Reviewed by the Scottish Energy Efficiency team.
Get a quote or call 0141 230 0198
Interest-free credit available, subject to status.