Solar Powered EV Charger for Business: What You Are Actually Buying
There is no single product called a solar powered EV charger that suits a business car park or depot. What exists is a system: panels, an inverter, one or more chargers, a controller and a grid connection that covers the gaps. The useful question is which of four builds fits your site, and how much of your vehicles’ energy the sun will supply once you have chosen it. The answer depends far more on when the vehicles are parked than on which charger carries the label.
Four ways to build a solar powered charging site
Every commercial “solar powered” charging installation is one of these, or a mix of them. The differences are where the panels sit, what steers the chargers, and whether anything stores energy.
| Build | What it is | Fits when | Watch for |
|---|---|---|---|
| 1. Roof or ground array plus ordinary AC chargers | Panels feed the building’s supply; standard chargers draw from the same supply; a load-management controller shifts charging into sunny hours. | Vehicles are parked on site in daylight; the building has its own daytime demand. | Needs a controller and metering, not just chargers. Charging that starts on arrival wastes most of the benefit. |
| 2. Chargers with a solar-surplus mode | The charger itself reads a grid meter and adjusts its current to follow the array’s surplus. | One to a few chargers; a simple site; no separate energy-management platform. | A charger cannot follow a surplus below its minimum current (see below), so a small array under a single charger often falls short. |
| 3. Solar canopy over the bays | The array is the car-park roof: panels on a steel canopy above the parking. | Roofs are unsuitable or tenanted; the car park is large; shade and weather cover for the vehicles are worth something. | Foundations, structure, drainage and planning drive the cost. See the canopy guide. |
| 4. Any of the above plus a battery | A battery stores daytime surplus for evening or overnight charging. | Vehicles are parked at night but the site generates in the day. | The model on this site does not include a battery. Ask for a quote that shows the saving separately from the array. |
The first build is the one most businesses end up with, because it is the least specialised: the panels are an ordinary commercial array and the chargers are ordinary chargers. What turns it into a “solar powered” installation is the metering and the control software, which is why the load-management guide matters as much as the hardware list. The seasonal swing is shown in does solar EV charging work in winter, and the options for vehicles parked overnight are in solar EV charging at night.
How much of the charging will the panels actually supply?
Panels produce most of their energy around midday and in summer. A vehicle can only take energy while it is plugged in. An hour-by-hour simulation using PVGIS data for 2005–2023 shows how large that mismatch is for a London array at a 10° pitch. If cars are parked 09:00–17:00 on weekdays, about 60% of the array’s yearly output is produced while they are there. An array half the size of their yearly demand then supplies about 30% of their energy, and an array equal to their demand about 56%, when the chargers follow the sun. For vehicles parked only overnight, about 3% of the output falls in their window, so even an array as big as their yearly demand supplies about 3%.
| 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% |
The same fleet with chargers that simply start at full power on arrival gets between 7% and 20% from an array half the size of its demand, depending on how much energy each vehicle needs a day. The hardware was identical; the specification was different. That is the single most important thing to put in a tender: solar-following control, in writing, with a stated target for the share of vehicle energy that comes from the array.
One car, in panels
It helps to see the scale for a single vehicle. A car doing 10,000 miles a year at 3.4 miles per kWh uses about 2,941 kWh from the wall. A London array at 10° produces about 904 kWh per kW a year, so matching that demand takes roughly 3.25 kW of array, or about 7.6 panels of 430 W. In Glasgow the same job takes about 9.0 panels. One 430 W panel supplies about 1.07 kWh a day on average over the year, so it takes roughly 28 days of one panel’s output to cover 100 miles. The panels-per-car breakdown gives the figures for eight UK cities.
For a fleet the arithmetic scales linearly, but the timing question does not: twenty vans doing 18,000 miles a year at 0.40 kWh a mile use 144,000 kWh, an average draw of only 16 kW across the year. The fleet depot guide works that example through, including the supply capacity it needs.
What the array costs, and what it earns
The Department for Energy Security and Net Zero’s 2025/26 solar PV cost data gives a mean installed cost of £1,167 per kW for non-domestic systems of 10–50 kW. At 430 W a panel that is roughly £500 of installed array per panel, an arithmetic conversion rather than a quoted price; larger arrays may cost less per kW, and the chargers, the controller and any canopy structure come on top. Over a 25-year life, with the standard degradation assumption of 0.5% a year, that cost works out at about 5.5p per kWh generated in London. Non-domestic grid electricity averaged 24.14p per kWh including the Climate Change Levy in the first quarter of 2026, so an array whose output is used on site has plenty of room to win; an array whose output is exported at an assumed 5p does not.
That is why the payback varies so widely. An array whose entire output is used pays back in about 5.3 years; the same array judged only on the vehicles it charges takes about 7.8 years for a workplace fleet that follows the sun, and about 23.2 years for an overnight fleet, because most of its output is exported. The break-even test and the calculator let you try your own parking hours. Tax relief on both the array and the chargers changes the picture again; the capital allowances guide covers it.
The minimum-current limit that catches small sites
The charging standard IEC 61851 sets a minimum charging current of 6 A per phase. The open-source evcc documentation turns that into 1.4 kW on a single phase and 4.1 kW on three. A charger therefore cannot follow a solar surplus that falls below those figures: it either stops or draws the difference from the grid. A depot with many chargers can concentrate a small surplus on one vehicle at a time, which is what the model assumes. A site with one charger and a modest array will use less solar than the tables show unless the charger can switch between single- and three-phase charging, which evcc describes as letting charging start from the single-phase minimum. Ask any supplier whether the charger switches phases and what the lowest surplus is that it will follow.
What to put in the specification
- A solar-share target, stated against your parking pattern, and the metering that will report it each month.
- Dynamic load management across all chargers and the building, with the supply limit set in the controller. See the load-management guide.
- An open charger protocol. Chargers that speak OCPP can be steered by any compatible controller. It is not a legal requirement, but it keeps you from being tied to one vendor’s software; the OCPP guide sets out what the law and the grant specification do and do not say.
- The grid side. Generation above the G98 limit needs a G99 application, and new charging load goes through the network operator’s own process. A combined application is often easier for the operator to accept, because load management flattens the profile it sees. See the grid connection guide.
- Funding that fits. The Workplace Charging Scheme and the Depot Charging Scheme pay towards the chargers, not the panels, so the specification should split the two in the quote.
- Handover proof. The monthly report should show the solar share of vehicle energy, building self-consumption and pence per mile by vehicle. Handover is not complete until it does.
When a solar powered charger is the wrong answer
If your vehicles are parked only overnight, the building has no daytime load, and a battery is not in the budget, panels will mostly export. Charge from the grid, ideally on an overnight tariff, and spend the solar budget where a quote shows it pays. If you only want the cheapest possible charging for a handful of staff cars, a plain managed charger on the grid supply, with panels added later, loses nothing and leaves the decision open. The business case page sets out the other benefits, which do not depend on the solar share.
Solar powered EV charger questions
Can I charge a van or car straight from solar panels?
Not through a dedicated cable. On a business site the panels feed the building’s supply, the chargers draw from the same supply, and a controller decides when charging happens. How much of the vehicles’ energy then comes from the panels depends mostly on when they are parked: about 30% for a workplace pattern with an array half the size of yearly demand, and about 3% for overnight parking even with an array as large as the demand.
Do I need a special solar charger?
Not necessarily. A standard AC charger on a site with solar and a load-management controller can follow the sun. Some chargers have a built-in solar-surplus mode that does it themselves; they suit a small site. Whichever you choose, ask for the lowest surplus the charger can follow, because the IEC 61851 minimum of 6 A per phase is 1.4 kW on one phase and 4.1 kW on three.
How many panels does one car need?
A car doing 10,000 miles a year uses about 2,941 kWh from the wall. In London that takes roughly 7.6 panels of 430 W to match over a year, and about 9.0 in Glasgow. The panels-per-car breakdown covers eight cities.
Is a solar powered charger worth it for a business?
It depends on parking hours and on whether the building uses the rest of the output. An array whose output is all used on site pays back in about 5.3 years; judged only on the vehicles it charges, a workplace fleet that follows the sun takes about 7.8 years and an overnight fleet about 23.2 years. See the break-even test.
Will a battery fix overnight charging?
A battery can move daytime surplus into the evening, which is the only way solar helps a fleet that is parked overnight. The model on this site does not include a battery, so ask for a quote that prices the battery separately and shows the saving it adds.
Does a grant pay for the panels?
The Workplace Charging Scheme and the Depot Charging Scheme pay towards chargers and, for the depot scheme, related civil works, not towards solar panels. Ask installers to split the panels and the chargers in the quote so each can be checked against the scheme. See the Workplace Charging Scheme and Depot Charging Scheme guides.
Sources
- EU Joint Research Centre, PVGIS 5.3 hourly series (SARAH3 radiation, ERA5 meteorology), 2005–2023; assumptions are set out on the calculator page.
- DESNZ, Solar PV cost data 2025/26 (£1,167 per kW mean, non-domestic 10–50 kW) and Quarterly Energy Prices table 3.4.2 (24.14p per kWh including CCL, Q1 2026).
- Jordan and Kurtz (2013), median PV degradation 0.5% a year, doi 10.1002/pip.1182.
- evcc documentation, “Solar surplus charging” — docs.evcc.io (IEC 61851 6 A minimum; 1.4 kW single-phase and 4.1 kW three-phase; phase switching).
- Zapmap Price Index, August 2026 (the 3.4 miles per kWh implied by its per-mile figures).
Checked 20 October 2026. Charger prices and the 25-year life are assumptions, labelled as such on the pages that use them.
Combined feasibility enquiry
Get combined solar + EV charging figures for your site
Tell us about the site and the vehicles. We reply by email with a written desk feasibility — array size, charger plan, grid headroom, grant and tax position — drawing on twelve months of meter data if you have it. No site visit is needed for that first pass.