Fast charger at a petrol station on a small grid connection?

A battery buffer lets a fast charger deliver its full power while the grid only sees what your connection can spare. A business battery sits between the grid and the charger, refills during quiet hours and covers the burst when a car plugs in. That way many petrol stations, brasseries, garages and shops can offer DC fast charging without a heavier connection.

You run a petrol station, a brasserie along a regional road, a garage or a shop with a car park. More of your customers drive electric, and they ask where they can charge while they eat, shop or wait. Then the electrician looks at your connection: one fast charger asks more power than your pumps, cooling and shop together. On a Belgian forum, someone who wanted to place a charger next to a row of shops did the sum himself. Two 22 kW outputs, 44 kW, at about 50 euro per kW per year: 2,200 euro a year in capacity tariff alone. "You will never earn that back," he wrote.

What is easy to miss: slow charging does not solve it either. Another forum member answered that shop visitors stay too short for an AC charger. Half an hour on a slow charger may not even cover the trip to the shop, so the driver does not come back. The real choice is fast charging that does not set your peak. That is the job of the battery.

How much power does a fast charger at a petrol station need?

A fast charger at a petrol station asks between 50 and 400 kW, depending on the model. The EU calls every charging point above 22 kW a high-power recharging point. Fast charging networks now build chargers of 150 kW and more.

Power levels: Vlaanderen.be (AC 3.7 to 22 kW, 50 kW DC example), EU Regulation 2023/1804 (high power above 22 kW) and Fastned (newest generation 300 to 400 kW).

The charger power is a maximum, not what every car takes. The car decides the charging speed, and it slows down from about 80% to protect its battery. That is why fast charging is meant for the first 80%, as the Flemish government puts it.

Which fast charger suits the stop your customers make?

Match the charger to how long your customers stay. A driver who fills up and pays needs a lot of power in a few minutes. A family having lunch has three quarters of an hour.

• Petrol station, 10 to 20 minutes: a 150 kW charger or more. At 50 kW, 15 minutes adds only about 70 km at best (our calculation).
• Brasserie, restaurant or roadside café, 30 to 60 minutes: a 50 kW DC charger already works. The Flemish government counts well over 100 km of range for half an hour at 50 kW, at 17 kWh per 100 km.
• Shop, supermarket or garage, 20 to 60 minutes: a DC charger of 50 kW or more. AC charging only suits staff and customers who stay for hours.
• Hotel or holiday site, overnight: AC charging is enough. Our article on charging stations for your business without a heavier connection covers that case.

A faster charger is not always better for you. It costs more, asks more from your connection and needs a bigger buffer. Choose the power your customers can use in the time they actually stay.

Why is your connection too small for a fast charging station?

Because a fast charging station adds a load that is often larger than your whole site, and a heavier connection is slow and expensive. In Flanders, Fluvius connects everything below 25 kVA on low voltage. Between 25 and 250 kVA the grid operator decides. Above 250 kVA you always go to medium voltage, with your own customer cabin.

• A study comes first. From 25 kVA, Fluvius makes a detailed study before it quotes. You pay for it even if you do not accept the quote: 493.90 euro excl. VAT for 56 to 1,000 kVA in 2026.
• Your own cabin. Above 250 kVA you supply and place the customer cabin, as close as possible to the public road.
• Grid congestion. In some areas Fluvius may postpone a new or heavier connection until the grid is reinforced.

Did Fluvius refuse or postpone your request? Then read our article on your options when a heavier connection is refused. Weighing a medium voltage cabin against a battery? Our comparison of a high-voltage cabin or a battery sets out the costs.

How does a battery buffered fast charger work?

The battery sits between the grid and the charger. The grid refills it at the power your connection can spare, and the battery supplies the rest when a car plugs in. The grid never sees the charger's full power.

A worked example, illustrative and internally consistent, not a customer case. A roadside site has about 50 kW to spare on its connection during the day. It installs a 150 kW DC charger. A car plugs in for 20 minutes and takes on average 100 kW, because its charging speed drops as it fills.

Without the battery, every fast session would add up to 150 kW to your peak; with it, the grid sees 50 kW. In a Victron system, the peak shaving function keeps grid offtake under a current limit you set, for the whole site. The battery covers what the charger and the shop need above that limit, as long as it has charge.

A farm in Tielt shows the principle. Its connection was too small to grow; a battery system now gives the site more power without a heavier connection.

When do drivers charge, and how big must the battery buffer be?

The battery buffer must cover your busiest stretch of the day, not an average day. Fast charging happens mainly in daytime, according to data from Fastned's own network. At a roadside site, that often means a morning, a lunch and an evening rush.

Quiet hours between the rushes are what make a small connection work. The battery refills in those hours. If cars queue all day, there is no time to refill, and the grid has to deliver the energy.

Solar panels on the roof or on a canopy over the charging bays help from spring to autumn. Then the sun shines during the lunch rush. In winter the grid does most of the work. Read what peak shaving is and when a battery pays off for the sizing logic behind the buffer.

What does a fast charger without a buffer do to your peak and your bill?

It sets your peak, and you pay for that peak every month, even when the charger is idle most of the time. Grid tariffs for businesses charge the power you draw, not only the energy.

In Flanders, on a low-voltage connection with a digital meter, the capacity tariff takes the average of your last 12 monthly peaks. In 2026 it costs about 53.39 euro per kW per year on average (excl. VAT). Every kW a charger adds to each monthly peak costs about that, before you sell a single kWh. Larger sites pay for their peak power in their own tariff; the principle stays the same.

How the capacity tariff works, and how to read your own peaks, is explained in how to calculate the capacity tariff for your business. For what else sets the peak of a site, read what drives the peak demand of a business.

Which rules apply when you sell fast charging to the public?

The EU rules for public charging points (AFIR) decide how your customers pay and how you show the price. They apply to whoever operates the charger: you, if you run it yourself.

• Payment without a subscription. Public charging points installed from 13 April 2024 must accept ad hoc payment. Think of a card reader or a contactless device that reads payment cards.
• Price per kWh up front. From 50 kW, the ad hoc price is based on the price per kWh, shown at the station before the session starts. An occupancy fee per minute is allowed.
• Older fast chargers along main roads. From 1 January 2027, this also applies to older public chargers of 50 kW or more along the TEN-T road network. "Along" means within 3 km of an exit.

Some owners rent space to a charging operator who installs and runs the chargers. The operator then deals with payment and pricing, and often with the connection too. If you own the chargers, those choices are yours. A battery of this size also has fire safety and permit rules: read whether a business battery is safe.

When is a battery buffer not the answer for a fast charging station?

When chargers run almost all day, a battery cannot refill and the grid must deliver the energy. A battery moves energy in time; it does not create it.

• A motorway hub with many chargers. Fastned connects its stations on medium voltage: a station with ten fast chargers needs a 1 MW connection. There the route is a cabin, with a battery as an option on top.
• Very few sessions. If a car charges twice a week, a smaller 50 kW charger without a buffer may fit your connection. Your quarter-hour data shows it.
• Overnight guests or staff cars. Slow AC charging with load management is cheaper than a DC charger and a battery.
• Trucks and buses. They need far more energy per session. Our article on charging electric trucks at your depot explains that case.

We tell you when the data shows that a battery does not pay off. Sometimes a slower charger, or a heavier connection with a buffer to bridge the waiting time, is the better route.

How do you plan a fast charger at your site?

Start from your customers and your connection, not from the charger catalogue. These questions decide the charger power and whether a battery buffer adds anything.

Size on your busiest day and your quietest hours, not on the average. That is where a buffer succeeds or fails.

What happens when you ask us to look at fast charging for your site?

We build DC charging with a business battery behind it, and we start from your site and your connection. Our business battery systems support fast-charging infrastructure, with chargers up to 180 kVA controlled on Victron equipment.

1. Step 1: Send us your quarter-hour data or your latest invoices, your connection size and your plan: charger power, expected sessions and opening hours.
2. Step 2: If data is missing, we can measure your consumption for a short period first. Our monitoring software shows consumption per phase, with reports per minute, hour or day.
3. Step 3: Analysis and sizing: which charger fits your customers, how big the buffer must be, or whether a heavier connection is better.
4. Step 4: Technical design, installation and commissioning.
5. Step 5: Monitoring and support.

Our business battery systems range from SME installations to modular systems up to 1 MW, combined with solar power and smart charging.