How a Home Battery Works with Solar and Smart Tariffs
Last updated: 17 October 2026
Tesla Powerwall 3 stores 13.5 kWh of electricity and delivers 11.04 kW continuously. It charges from solar panels or cheap grid electricity, then powers your home when rates are high or the sun is not shining. During a power cut, it switches to backup mode automatically in milliseconds.
What Tesla Powerwall 3 does
Tesla Powerwall 3 is a rechargeable lithium-ion home battery that stores 13.5 kWh of usable electricity and delivers 11.04 kW of continuous power on UK single-phase supply. It charges when electricity is cheap or abundant — from solar panels, from the grid during low-rate periods, or both — and discharges to power your home when rates are high or the sun is not shining.
How Powerwall works with solar panels
When paired with solar panels, Powerwall stores excess electricity generated during the day instead of exporting it to the grid for a low rate. You then use that stored energy in the evening, avoiding peak-rate grid electricity. Powerwall 3 includes an integrated DC-coupled solar inverter with up to 20 kW capacity. If you already have solar, Powerwall 3 can AC-couple with your existing inverter.
How Powerwall works with smart tariffs
Even without solar, Powerwall can save you money by charging during cheap off-peak periods and discharging during expensive peak periods. Tariffs such as Octopus Intelligent Flux offer low overnight rates — Powerwall charges automatically during these windows and powers your home during the day. The Tesla app's Time-Based Control mode manages this automatically.
Backup power during outages
Powerwall 3 detects power cuts and switches to backup mode automatically in milliseconds. With a Backup Gateway, it can provide whole-home backup. Storm Watch mode monitors Met Office weather data and automatically charges to 100% before forecast severe weather.
What gets installed
A typical Powerwall 3 installation includes the battery unit itself (wall-mounted, indoor or outdoor), a Backup Gateway (if whole-home backup is required), connection to your consumer unit, the Tesla app for monitoring and control, and G99 DNO notification to SPEN or SSEN. The physical installation typically takes one day.
The full timeline from enquiry to switch-on
1. Enquiry: Submit the form or call 0141 230 0198. We arrange a no-obligation site survey within 1–2 working days.
2. Survey and design: We assess your consumer unit, mounting location, solar compatibility, and backup requirements. You receive a written quote within 48 hours.
3. DNO application: We submit the G99 application to SPEN or SSEN on your behalf. Approval typically takes 11–30 working days.
4. Installation: The physical installation takes one day. All wiring, gateway configuration, app setup, and DNO post-installation notification are handled for you.
5. Commissioning: Your system is configured, tested, and handed over with a full walkthrough of the Tesla app.
Can I add a battery to my existing solar panels?
Yes. Tesla Powerwall 3 AC-couples with your existing solar inverter, storing excess generation instead of exporting it for a low rate. Our MCS-certified installation partners assess compatibility during the survey and confirm whether any changes are needed.
Is finance available?
Finance available, subject to status. Call 0141 230 0198 to discuss your options and find out whether finance is suitable for your circumstances.
How do I get a quote?
Call 0141 230 0198 or use the form on this page. We arrange a no-obligation site survey, then send a written quote within 48 hours. There is no pressure to proceed.
Do you install in my area?
We cover all Scottish postcodes — Glasgow, Edinburgh, Aberdeen, Dundee, Inverness, the Highlands, Islands, and everywhere in between. Both SPEN and SSEN DNO areas are handled.
Get your quote
No obligation · We install through MCS-certified partners · Scottish homes