How to manage shared EV chargers in a company car park

Why shared chargers cause conflicts

The problem is rarely a lack of chargers; it is how they are occupied. An employee arrives at 8:30 with the battery at 40 %, plugs in and goes to work. By 10:30 the car is fully charged, but it stays there until 6 pm. Meanwhile, three colleagues have been circling the car park looking for a free charger.

This happens for three reasons:

• An office charger is thought of as a full-day spot, but a charge only needs one or two hours. If the spot is allocated by whole days, most of its time is wasted.
• There is no incentive to move the car. Without a clear rule, nobody knows how long is reasonable and nobody wants to be the first to interrupt.
• Hybrid work changes demand every day. A fixed Monday-to-Friday split leaves chargers empty some days and queues on others.

The answer is not to buy more chargers blindly, but to share the time of the ones you already have more effectively.

Before deciding anything: measure real demand

Four numbers tell you whether your problem is one of quantity or of sharing:

1. How many people have an electric or plug-in hybrid car and want to charge at the office.
2. How much energy each one needs per day. A 40 km round-trip commute at 15 to 20 kWh/100 km is 6 to 8 kWh.
3. How many days a week they come to the office.
4. What time they arrive: if everyone arrives between 8:00 and 9:30, the peak matters, not the daily average.

An example with starting figures you can replace with your own: a single-phase 32 A charger delivers about 7.4 kW (230 V × 32 A). A driver who needs 7 kWh takes close to an hour. In an eight-hour day, with a 15-minute buffer between slots, about 6 charges fit per charger in theory and between 4 and 6 in practice.

If you have 30 drivers who need 1.5 hours on average and come in three days out of five, daily demand is 30 × 1.5 × 0.6 = 27 charger-hours. Divided by about 6 usable hours per charger, that is around 4 or 5 chargers. With first come, first served, on the other hand, every car stays plugged in all day: with 18 drivers present each day (30 × 0.6) you would need up to 18 chargers so that nobody is left without a charge. These figures are indicative: arrival times and car models can move the result.

Keep in mind that many cars do not accept more than 7 to 11 kW on AC, so a 22 kW charger is rarely used to its full capacity in an office.

Five models for sharing the chargers

With fewer than five drivers per charger, a well-agreed rotation may be enough. Beyond that, time-slot booking is the only option that keeps sharing fair without someone having to referee every day.

A usage policy in 7 rules (ready to copy)

Whatever model you choose, these rules prevent almost every conflict. You can copy them, adapt them and publish them on your intranet.

1. Who can use the chargers. For example: employees with an electric or plug-in hybrid car. Decide whether visitors and fleet vehicles are included.
2. Maximum duration per slot. One or two hours cover most daily needs. If someone needs more, they book two consecutive slots.
3. Booking window. Limit how many days ahead people can book (for example, 3 days) so nobody reserves the whole week.
4. Grace period to move the car. Fifteen minutes after the slot ends, and then the spot is free again for the next person.
5. If you will not use your slot, cancel it. A slot cancelled in time is a charge for a colleague.
6. Reasoned priorities. For example, people with reduced mobility or service vehicles. Document them; do not improvise them.
7. How to report a fault. A broken charger that nobody reports blocks everyone. Define a clear channel and who responds.

A rule that cannot be checked will not be followed. That is why each slot should have a name and a time that everyone can see.

Who pays for the electricity

There are three common options:

• Free for the employee, as a benefit. It is the simplest and is usually acceptable when consumption is low.
• Flat fee per slot or per month. It covers the average cost without having to measure each charge.
• Pay per kWh used. It is the most accurate, but it needs chargers with a meter and a system that records each session. Many chargers connect to central software through OCPP, an open protocol for managing chargers from different manufacturers.

Decide this before installing, because it determines which chargers you buy. Also, the tax treatment of offering free charging to employees varies by country, so check with your advisor.

Important: a parking-booking tool decides who charges and when; it does not measure kWh or bill for them. That is done by your chargers' own system. They are two layers that complement each other.

Are you required to install charge points?

More and more. The Directive (EU) 2024/1275 on the energy performance of buildings (the recast EPBD) requires Member States to demand charging infrastructure in non-residential buildings. For existing non-residential buildings with more than 20 parking spaces, the directive sets 1 January 2027 as the date: one recharging point for every 10 parking spaces or, as an alternative, ducting for at least 50 % of the spaces. For new buildings or those undergoing major renovation, the requirements are stricter.

The details (how many points, whether pre-installation is accepted instead of a charger, exceptions) depend on how each country has transposed the directive. Check the national and regional rules that apply to you before sizing the installation. If you are going to have to install chargers, it is better to design the usage policy at the same time.

To see how many charging points apply to your car park, use the EV charging requirements calculator.

How to do it with LoomiSpot

LoomiSpot is office parking management software that includes EV charger booking by time slot. This is how the rules above are applied:

• Mark any spot as an EV charger and book by start time and duration (1, 2, 4 hours or whatever you allow). Several cars share the same charger in turns on the same day.
• The spot is free again when the slot ends, without anyone having to do anything.
• You decide the booking window: how many days ahead people can book.
• Report issues from the app: if a charger does not work, the user reports it, follows its status (open or resolved) and chats with the admins in a thread.
• Web, iOS and Android with the same interface for admins and employees.

EV charger booking by time slot is included in the free plan, which allows up to 10 spaces and 15 users. LoomiSpot manages who charges and when; it does not measure kWh or bill for the electricity.