Solar, Storage and EV Charging: A Commercial System Guide

A solar, storage and EV charging system combines solar generation, a battery and electric vehicle chargers under coordinated control. For a commercial site, the right configuration starts with vehicle energy needs, charging times and available grid capacity—not with the largest battery or fastest charger. Solar supplies energy when sunlight is available; storage shifts energy and supports short power peaks; chargers deliver it to vehicles. This guide explains how to match those three parts, with a worked sizing example and BENY product options.

When Does Solar + Storage + EV Charging Make Sense?

Start with the problem the site needs to solve. Are vehicles waiting for power, is useful solar generation being exported, or does charging create an expensive electricity peak? These are different problems and may need different configurations. Alternating-current (AC) charging and direct-current (DC) fast charging serve different parking and vehicle requirements.

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Not every charging site needs a battery. If the grid connection is adequate and vehicles can charge slowly, solar plus managed charging may be the simpler investment. Compare that option with a full storage system before buying additional equipment.

The Joint Office’s battery-buffered charging guidance explains both the opportunities and the trade-offs: storage can support grid-constrained charging, but it adds capital cost and another equipment failure point. An undersized battery can run out of energy and force charging power down.

How the Three Parts Work Together

Photovoltaic (PV) panels generate electricity. A battery energy storage system (BESS) stores energy and releases it later. EV chargers supply vehicles, while an energy management system (EMS) coordinates the site’s power limits and operating priorities.

Conceptual energy relationships only—not an electrical installation or wiring diagram. The power conversion system (PCS) converts power between the battery and the AC distribution system.

Two numbers matter throughout this guide: kilowatts (kW) describe how quickly power is supplied; kilowatt-hours (kWh) describe how much energy is supplied or stored. A charger needs a suitable power rating, and a storage system needs both power and energy ratings.

AC-coupled or DC-coupled?

In an AC-coupled arrangement, solar, storage and conventional chargers connect through AC distribution and their respective converters. This can suit an existing building with an installed solar inverter. In a DC-coupled design, compatible solar, battery and charging equipment exchange energy through an engineered DC architecture. The interfaces and controls must be designed together.

Size the Charging Service Before the Battery

Write down how many vehicles arrive, the energy each needs and how long each can stay. Charging speed should serve that schedule. A high charger nameplate rating is not useful if vehicles cannot accept that power or if the site cannot sustain it.

Daily energy and parking time

Suppose 12 vehicles each need 30 kWh added to their batteries. The daily vehicle energy requirement is 12 × 30 = 360 kWh. With an illustrative 95% efficiency from charger AC input to vehicle battery, that represents about 379 kWh at the charger input. Building demand, battery-storage losses and auxiliary consumption are additional.

For one vehicle, adding 30 kWh over six hours requires an average of 5 kW delivered to its battery. The same energy over 30 minutes requires an average of 60 kW. These are planning averages, not guaranteed charger outputs: vehicle limits, charging taper and losses still apply.

Concurrent power and connector allocation

Check which vehicles actually charge at the same time. Separate the station’s total rating from each connector’s allocation. Two connectors on a 120 kW station do not, by themselves, mean two vehicles can each receive 120 kW simultaneously.

For AC charging, confirm the vehicle’s onboard charging limit and the site’s single- or three-phase supply. For DC charging, check the vehicle’s voltage, connector, charging curve and the charger’s power-sharing behavior.

Battery Sizing: Check Both kW and kWh

Kilowatts (kW) measure power; kilowatt-hours (kWh) measure energy. A battery must provide the required power and enough usable energy for the operating period. Increasing capacity does not automatically increase the PCS power rating.

A worked commercial-site example

The following is a hypothetical screening calculation for an AC-coupled site. Every power figure is measured at the site’s AC distribution boundary. It is not a BENY quotation or a final engineering design.

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The 65.8 kWh result covers only that isolated event under those assumptions. It does not mean a 66 kWh battery can necessarily deliver 100 kW. The battery’s permitted discharge rate, PCS, operating temperature and available state of charge (SoC) must all support the power requirement.

If 180 kW instead refers to DC output delivered by the chargers, the calculation changes. At an assumed 95% charger conversion efficiency, charger AC input is about 189.5 kW, so the storage power requirement becomes approximately 109.5 kW. Mixing input and output ratings understates the required storage power.

Before choosing equipment, simulate repeated charging events and the time available to refill the battery. Include battery degradation, auxiliary loads, reserve policy and expansion. Two identical peaks without intervening recharge need more energy than one.

Match Solar Production and EMS Control to the Charging Schedule

Solar array size is normally expressed in peak kilowatts (kWp), a rating under standard test conditions. It is not a promise of that output throughout the day. Use a location-specific solar production model, seasonal conditions and the site’s load profile rather than a fixed “panels per charger” rule.

Daytime workplace charging may use solar directly. Evening fleet charging may require stored daytime surplus or grid energy. A design that looks balanced using annual solar generation can still struggle on a busy winter evening.

Give the EMS an agreed operating order:

1. Respect the site import limit and equipment operating limits.
2. Meet vehicle departure requirements by allocating charging power to the right vehicles.
3. Use available solar for current loads and permitted battery charging.
4. Preserve the chosen battery reserve and schedule recharge before the next busy period.
5. Define safe fallback behavior when communications fail or the battery reaches its minimum SoC.

The Open Charge Point Protocol (OCPP) supports communication between charging equipment and a charging management system. An OCPP label alone does not demonstrate complete integration with a site’s battery, PV inverter or EMS. Ask the suppliers to demonstrate the required commands, metering and fallback behavior together.

BENY Storage and Charging Options for the System

For a modular commercial project, compare a separate storage cabinet and charging station with a compact battery-integrated charger. They solve different site constraints; neither is a universal replacement for the other.

125 kW / 261 kWh liquid-cooled storage

BENY’s 125 kW / 261 kWh Liquid Cooling Energy Storage System combines lithium iron phosphate (LFP) batteries, a battery management system, PCS, cooling, fire-protection equipment and energy management in one cabinet. Its published table lists 125 kW rated AC power and 261 kWh battery capacity. This makes it a candidate for projects requiring both a meaningful power buffer and a longer energy window. Selection still depends on the actual load profile, installation conditions and control requirements.

BDC two-connector DC charging stations

The BENY BDC DC charging station range lists models from 60 to 320 kW, two charging connectors and OCPP 1.6 support. Its published input specification is three-phase AC, so it belongs on the AC side of a compatible installation—not directly on an arbitrary battery DC bus. Confirm the selected model’s connector options, station-level rating, simultaneous output allocation and regional configuration before ordering.

A compact battery-integrated alternative

For a different deployment format, BENY’s battery-integrated EV charger lists 60/80 kW charging options and a 42.5 kWh battery. It can be evaluated where an integrated unit is preferable to separate equipment. Do not equate maximum charging power with unlimited continuous operation. Confirm input power, usable energy, recharge time and any proposed solar interface for the exact configuration.

Explore BENY’s industrial and commercial energy storage range and commercial EV charging products when comparing project formats.

Project Example: Solar, Storage and DC Charging in Thailand

BENY’s published Thailand solar-storage-charging project describes an industrial electric-truck installation using a 240 kW maximum power point tracking (MPPT) cabinet, a 100 kW / 241 kWh air-cooled storage system and a 240 kW charger with DC input and DC output.

This is a project-specific direct-DC architecture, not proof that every conventional charger supports direct DC input. The MPPT cabinet rating is not a stated PV-array size, and the 100 kW storage rating does not mean the battery alone can sustain 240 kW charging. Available power must be assessed across the operating conditions.

The example illustrates integration choices. It is a manufacturer-published project description, not an independently audited savings or performance guarantee for another site.

What to Include in a Solar-Storage-Charging Quotation

A useful request for quotation describes the required service, not just a list of product ratings. Include:

• Site and supply: country, grid connection, approved import/export limits, electricity tariff and measured building-load profile.
• Vehicle demand: vehicle types, connector requirements, arrivals, departure deadlines, energy per session and expected concurrent charging.
• Solar conditions: existing or planned array, inverter details, estimated production profile and available space.
• Storage duty: required power, usable energy, recharge windows, reserve policy and expected operating cycles.
• Integration and delivery: system architecture, EMS responsibilities, charger power sharing, metering, commissioning tests, warranty and local service.

The U.S. Department of Energy’s charging-infrastructure procurement checklist also emphasizes utility coordination, future expansion, permitting and ongoing operating costs. Apply the requirements of the actual installation country; a product family’s certification claims do not replace verification of the supplied model.

Assess the business case using the local tariff and an hourly or suitably finer dispatch model. Include equipment, construction, controls, maintenance and replacement costs. Do not count the same battery energy twice as both a protected backup reserve and freely available peak-shaving capacity.

This guide supports early project planning. Final design, protection, battery fire safety, grid connection and commissioning require qualified professionals and local approvals.