Determining the number of charging stations needed for your company’s parking lot is crucial. You want to ensure that your employees have convenient access to charging, but at the same time, you don’t want to overspend. While the charging stations are visible, the invisible infrastructure and network that power them rely on copper wiring, which can be quite costly.
This decision is not straightforward, as several factors influence the number of charging stations required. These factors include the range of the electric vehicles (EVs), the distance between the parking lot and the office, the frequency of office visits, the employees’ ability to charge their vehicles at home, and other considerations.
Additionally, the available power supply must be taken into account. I recommend implementing load balancing. This method prioritizes electrical power for critical infrastructure, such as the office building, warehouse, and manufacturing unit. Only the remaining electrical energy should be allocated to the charging stations, where it can be redistributed among all connected vehicles. If this redistribution results in charging speeds that are too slow, structural interventions—such as installing a higher-capacity transformer—may become necessary.
To estimate the lower limit of the number of charging stations needed, I have successfully used the following formula as a rule of thumb. This approach provides a starting point, allowing expansion later if required.
The formula will yield the number of charging stations, each with two charging connections.
For clarification, you can estimate the number of charges per week for each EV as follows: If most employees come to the office twice a week and charge each time, then the number of charges per week per EV is 2. If they attend every day, this number would be 5, although that scenario is unlikely.
The variable “Session” is equal to 1 if employees can charge their vehicles for a full day. However, if they are only allowed to use the charging station for half a day (for example, if there’s a mandatory shift change at noon), then “Session” should be set to 0.5.
Here’s a practical example:
– Number of EVs: 100
– Number of charges per week per EV: 2 (e.g., due to mandatory office days on Tuesdays and Thursdays)
– Session: 1 (employees can park at the charging station for the entire day)
Using the formula, the result would be:
100 x (2/5) x 1 x 0.5 = 20 charging stations with 2 charging connections needed.