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How Many EV Chargers Can I Install? EV Charging Systems in Existing Buildings

When installing EV chargers into an existing building, a key step is figuring out how many chargers the building can handle. This is a deceptively complicated question to answer as there are multiple factors that need to be considered including: building type, electrical distribution system, historical load data, type of charging system to be installed, predicted demand, etc. Due to the interactions and interconnectivity between these, it is important to work with professionals with extensive experience in energy projects.

Existing Conditions: Building

The first step in identifying the right charging system, including number of chargers, is a feasibility study. This involves a detailed site visit to collect information and an analysis of load data from electric bills and coordination with the utility. Building use is especially important as that determines its load profile, electrical infrastructure, and expectations from users.

For example a high-rise condo building has a reduced electrical demand at night and residents that expect relatively cheap overnight charging in their own parking stalls, while a supermarket will have customers that will expect faster charging at a premium while they shop.

Charging Systems: More Than Just Chargers

Another major factor in determining the number of chargers is the type of chargers being installed. Not all chargers are the same, depending on the type of building and users there is a choice between level 2 and level 3 chargers. The table below compares the different charger levels

Charger Type

Supply Voltage

Approximate Range/hr of Charge

Approximate Time to Fully Recharge a Battery

Level 1

120 V AC

8 Km

30 h

Level 2

240/208 V AC

30-50 Km

4-10 h

Level 3 (DC Fast Charger)

480 V AC

>100 Km

25-30 mins (80%)

As seen in the table as charger level increases, the power draw also increases while decreasing the charge time. Level 2 chargers are typically used for overnight charging in residential buildings, while level 3 chargers are more ideal for destination charging and public use.

Beyond the chargers themselves, when multiple chargers are planned it is important to monitor and control electrical load to avoid overloading your building. Networked chargers allow for dynamic load management, reducing power consumption during peak load hours. Communication between the charger system and the building is the key to getting the most out of chargers and future scalability.

How We Can Help

Not sure where to start? If you are interested in EV charging for your building, have your tenants/building users fill out our building user survey to get an idea of how many chargers are needed now and in the near future to plan accordingly.

Mann Energy Solutions (MES) is a professional consulting engineering company that specializes in electrical and energy solutions, including engineering and implementation. Our experienced engineers can help work with your building’s unique profile to identify spare electrical capacity, energy saving opportunities, and design the best system for you. We have extensive experience with energy retrofits that make the most of your existing electrical capacity by optimizing building processes and equipment such as lighting, mechanical systems, electrical loads, and building envelope to reduce your energy use.

Our firm has hundreds of installed electrical and power projects and we have been in business since 1983. Some of our services include:

  • Free site walk-through by our experienced engineers and technicians to provide an initial site assessment

  • Engineering feasibility studies

  • Incentive study and application

  • Engineering, Procurement and Construction (EPC) for a turnkey project

  • Coordination with utilities for distribution system upgrades, service size expansions, and microgeneration through solar PV and cogeneration

For more information or a complimentary assessment contact us through the main site,, or call (905) 597-5855.



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