Commercial Solar for EV Fleet Charging: How Much Solar and Battery Storage Do You Need?

The right solar system for an electric vehicle fleet depends on how far the vehicles drive, when they return to base, how quickly they must recharge, and what electricity the rest of the business uses. A warehouse or depot may be able to use rooftop solar for daytime charging; businesses with overnight-only charging may need a different combination of solar, load management, battery storage and grid supply. There is no reliable rule that one EV requires a fixed number of solar panels.

An office or warehouse can have predictable lighting, air conditioning and equipment loads. Adding several electric cars, vans or trucks introduces an additional electricity requirement—and potentially substantial spikes in electrical power demand if they plug in simultaneously.

This creates two distinct design questions: Energy (kWh): How much electricity must be delivered over a day or week?
Power (kW): How quickly must the vehicles recharge, and can the site supply that rate?

Solar sizing addresses the energy opportunity. Chargers, electrical infrastructure and load management determine charging capacity.

Start with actual driving rather than a headline EV battery capacity.

Daily driving energy (kWh) = number of vehicles × kilometres per vehicle per day × vehicle energy use (kWh/100km) ÷ 100.

Imagine a business with 12 electric vans. Each travels 80 km per operating day, and the planning assumption is 20 kWh/100 km.

12 × 80 × 20 ÷ 100 = 192 kWh per operating day of vehicle driving energy.

The actual electricity drawn at the charger will be higher once charging losses and site conditions are considered. These are illustrative assumptions, not MPV Solar performance guarantees or a recommended system size.

Then map this energy against the daily charging window. Replacing 192 kWh over a long overnight shift presents a very different power requirement from recovering that energy in two hours between delivery runs.

For an initial estimate, compare the site’s annual and seasonal charging energy with modelled solar generation, then test how much solar the fleet can actually use at the time it is generated.

On many Sydney sites, charging opportunities fall into three patterns:

Vehicles parked during the day: Workplace vehicles, service vans and shift vehicles may make good use of daytime solar if charging can occur during generation hours.

Vehicles away all day, back at night: Rooftop solar may mainly offset the site’s other daytime loads unless a battery or alternative charging schedule is economical.

Mixed or rotating fleet: Smart charging can allocate solar energy to vehicles that are on site, prioritising departure deadlines and battery state of charge.

Roof orientation, shaded areas, weekend operations and solar export limits all affect the outcome. MPV Solar’s Commercial Solar for Industrial Buildings explains why system size should be based on business energy data rather than roof area alone.

Imagine ten chargers capable of drawing 7 kW each. If all run at their rated power simultaneously, the potential combined charger load is 70 kW before other building demand. The site may not have enough spare capacity to support that unmanaged load.

Smart charging or load management can stagger sessions, cap total charger demand and prioritise vehicles that depart first. The actual arrangement depends on charger compatibility, vehicle limits, switchboards, protection and available supply.

Larger trucks and short-turnaround operations may need higher-power charging and more significant electrical infrastructure. A depot should be designed around vehicle schedules and load profiles, not just charger count.

Possibly. A commercial battery may store excess solar during daylight hours and discharge when vehicles return later. It may also help manage some peak demand, subject to power rating and operating strategy.

But a battery does not create energy. If your solar generation is regularly consumed by the existing facility, storage may not have much excess solar available to charge. If vehicles can charge directly at midday, solar-only plus smart chargers might be the more economical initial design.

It helps to compare at least three scenarios: solar with managed charging; solar plus commercial battery; and grid-based managed charging with provision for future solar or storage.

For financial modelling, see Commercial Battery Payback & ROI. The ROI guide owns the savings calculation; this article focuses on fleet load planning.

Potentially, but only if the system reduces the relevant metered demand during the tariff’s measurement period. A short burst of multiple chargers can still set a demand peak if it exceeds the battery’s discharge capability or occurs when storage is depleted.

Fleet charging should therefore be coordinated with the site’s main electrical demand. For a deeper explanation of this tariff mechanism, read How Batteries Cut Peak Demand Charges for Sydney Businesses.

MPV Solar would assess the existing switchboard, three-phase supply, spare capacity, metering, transformer and network connection, proposed AC or DC charging equipment, parking layout, cable routes and future fleet growth.

For a site within Ausgrid or Endeavour Energy territory, the proposed solar, battery and chargers may need different approvals or technical assessments. Installation timing depends on those assessments, equipment selection and any network augmentation. Never purchase a full bank of chargers before the electrical capacity and charging model have been tested.

Often it is worth investigating. A warehouse with an existing system might already export energy on weekends or outside operating hours, while the future fleet may need electricity after sunset. Adding panels, storage, smarter charging controls or a supply upgrade should be compared as separate options.

MPV Solar can review Warehouse Solar Installation Sydney and Commercial Battery Storage Sydney options as part of a staged plan.

For eligible mid-scale solar systems installed from 1 October 2026, Australia’s Small-scale Renewable Energy Scheme has expanded to 1 MW, with a fixed five-year deeming period and applications expected to open mid-to-late November. Eligibility and the choice of certificate pathway need project-specific review. The incentive changes project economics but does not determine the correct solar size.

Read MPV Solar’s Commercial Solar Rebate Australia 2026 after that existing guide is updated to reflect commencement.

For a useful initial assessment, gather the current electricity bill and interval data, the site address and network details, existing solar specifications, number and type of vehicles, average daily kilometres, arrival/departure times, parking plan and likely fleet growth.

MPV Solar can use these inputs to develop a whole-site energy concept rather than recommending panels and chargers independently.

Explore Commercial Solar and Commercial Battery Storage Sydney.

Planning to electrify company vehicles? Send MPV Solar your fleet schedule and recent electricity usage so we can assess solar, battery storage and the site’s electrical readiness together.