How Many Solar Panels Does It Take to Charge One Electric Car?
Published 14 October 2026 · Commercial Solar EV Editorial
For a car doing 10,000 miles a year, matching its yearly electricity takes about 7.6 panels of 430 W in London — roughly 3.25 kW of array. But “how many panels” has two different answers, and the difference matters more than the panel count: the number that matches the car’s energy over a year, and the share of the car’s charging that those panels will actually supply. This post works through both with published data and a stated model.
The energy sum
A typical electric car covers about 3.4 miles per kWh — the figure implied by Zapmap’s own per-mile conversions of its August 2026 prices — which is 0.294 kWh a mile. Ten thousand miles is therefore about 2,941 kWh a year, measured at the charger. A 430 W panel on a 10° south-facing roof in London produces about 389 kWh a year (PVGIS hourly data, 2005–2023, 14% system losses), which is 1.07 kWh a day on average. To give one 100-mile top-up of about 29 kWh, one panel needs roughly 28 days of average output. A single panel is therefore a trickle; a car is charged by an array.
Panels needed by city
The table gives the array that would match half of the car’s yearly energy (0.5×) and all of it (1×), with the panels that implies at 430 W — an assumed module rating — and the share of the car’s charging energy the array supplies if the car is parked 09:00–17:00 on weekdays and the charger follows the sun.
| City | Array for 0.5× (kWp) | Panels at 430 W | Solar share, workplace pattern | Array for 1× (kWp) | Panels at 430 W | Solar share, workplace pattern |
|---|---|---|---|---|---|---|
| Birmingham | 1.7 kWp | 4 | 30% | 3.4 kWp | 8 | 55% |
| Cardiff | 1.6 kWp | 4 | 30% | 3.2 kWp | 7 | 55% |
| Edinburgh | 1.9 kWp | 4 | 30% | 3.7 kWp | 9 | 54% |
| Glasgow | 1.9 kWp | 5 | 30% | 3.9 kWp | 9 | 53% |
| Leeds | 1.8 kWp | 4 | 30% | 3.5 kWp | 8 | 55% |
| London | 1.6 kWp | 4 | 30% | 3.3 kWp | 8 | 56% |
| Manchester | 1.9 kWp | 4 | 30% | 3.7 kWp | 9 | 54% |
| Southampton | 1.5 kWp | 4 | 30% | 3.1 kWp | 7 | 56% |
Two features of the table are worth noticing. First, the north–south gap is real but modest: matching the car’s yearly energy takes about 9.0 panels in Glasgow against 7.6 in London, because a Glasgow array produces about 16% less. Second, an array matching the car’s whole yearly energy supplies about 53%–56% of its charging, not 100%, for a simple reason: in summer the array produces more than a car parked for eight hours can absorb, and in winter it produces much less than the car needs.
The share the panels actually supply depends on parking hours
The same array supplies very different fractions depending on when the car is plugged in. For a London array equal in yearly output to the car’s yearly demand, with solar-following charging:
| When vehicles are plugged in | Share of the array’s yearly output that falls in that window | Array = 0.25× yearly vehicle demand | Array = 0.5× yearly vehicle demand | Array = 1× yearly vehicle demand | Array = 2× yearly vehicle demand |
|---|---|---|---|---|---|
| Workplace parking 09:00–17:00, Mon–Fri | 60% | 15% | 30% | 56% | 77% |
| Daytime depot dwell 10:00–16:00, Mon–Fri | 50% | 12% | 25% | 49% | 73% |
| Overnight depot 18:00–07:00, Mon–Fri evenings | 3% | 1% | 1% | 3% | 6% |
A car parked overnight, 18:00 to 07:00, gets only about 3% of its energy from panels even with an array matched to its yearly demand, because only about 3% of a year’s array output falls in that window. A car parked at work during the day can take about 56% from an array matched to it. That is why the question for a business is less “how many panels?” than “when are the vehicles here?”. The same model drives the calculator.
The charger matters too
The figures above assume the charger follows the sun. A charger that starts at full power when the car plugs in takes much less: for the workplace pattern and an array half the car’s yearly demand, 7% to 20% of the energy comes from solar instead of 30%, depending on how much energy the car needs each day. The control layer is covered in how solar EV charging works, including the 6 A minimum charging current (1.4 kW on a single phase, 4.1 kW on three) that stops a charger following a very small surplus. For a fleet, the arithmetic scales per vehicle — see the panels-per-van guide for vans and the fleet depot charging guide for a 20-van depot.
What this does not cover
- The array is treated as dedicated to the car, with any surplus exported; a building that also uses daytime power will take some.
- No battery is modelled, and weekends and bank holidays are ignored.
- London’s yearly output ranged from 861 to 978 kWh per kW between 2005 and 2023, so any single year can differ from the average by several per cent.
- Panel rating (430 W) and the car’s energy use are assumptions; use your own.
Sources: PVGIS 5.3 hourly series (EU JRC, SARAH3 radiation), 2005–2023, 10° south-facing, 14% losses; Zapmap Price Index, August 2026 (3.4 miles per kWh implied). Checked 14 October 2026.