Solar & EV Charging: Detailed Guide
Sizing solar around an EV or heat pump?
Both change your consumption profile substantially, which changes the system you need. Get a size and price built around your actual load.
Size a System for My HomeFree calculator. See your result before giving any details.
How much do solar panels save on EV charging?
Solar panels save £400-£550/year on EV charging vs grid rates. With Octopus Go (7.5p overnight), annual EV cost drops to £68-£200. A Zappi charger (£800-£1,100) automatically diverts surplus solar to your car. The optimal setup: 5-6kW solar + Zappi + Octopus Go = total home+car savings of £1,000-£1,450/year.
The Complete Solar EV Setup
Optimal configuration: 1. Solar panels: 5-6kW (13-16 panels) — £6,500-£11,000 2. Zappi smart charger: £800-£1,100 3. Octopus Go tariff: free to switch (7.5p overnight)
Daily routine: - Daytime: Zappi charges EV from surplus solar (free) - Overnight: Octopus Go charges any remaining need (7.5p/kWh) - Result: EV costs £68-£200/year vs £559 at standard grid rate
Source: Zappi specs; Octopus Go rates; DfT average mileage.
Sizing solar around an EV or heat pump?
Both change your consumption profile substantially, which changes the system you need. Get a size and price built around your actual load.
Size a System for My Home
Real-World Scenarios
Work from home: Car parked all day → Zappi diverts all surplus solar → 5,000-8,000 free miles/year. Annual cost: £30-£80.
Commuter: Car away during solar hours → overnight Go charging at 7.5p → weekend solar top-ups. Annual cost: £120-£200.
Part-time home: 2-3 days home per week → mix of solar and overnight. Annual cost: £60-£120.
All dramatically cheaper than petrol (£1,176/year) or standard grid EV (£559/year).
Source: Usage modelling.
Frequently Asked Questions
Related guides
Related: Home Heating Systems
Solar panels are most powerful when combined with an efficient heating system. Heat pumps use solar-generated electricity to heat your home at 300-400% efficiency — making them the ideal partner for solar.
Heat pumps use electricity at 300-400% efficiency, making them ideal partners for solar.
From our sister site Home Heat Pump Guide
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Sizing solar around an EV or heat pump?
Both change your consumption profile substantially, which changes the system you need. Get a size and price built around your actual load.
Size a System for My HomeFree calculator. See your result before giving any details.