Powering Up: EV Charging Solutions for Multi-Family Projects

Best practices for Electric Vehicle (EV) charging in a multifamily building
As the EV market continues to gain momentum, the need for EV charging capacity will only increase. All multifamily buildings will need to consider how to provide the charging infrastructure needed to fulfill this demand and create a more sustainable future. The high cost of development leaves most developers and owners budget constrained; this is why it becomes imperative to provide the most responsive charging system. This piece will consider the practical realities of what an EV driver desires and needs from a charging system and offer solutions for the most cost-effective way to deliver the most expansive system possible. You’ll learn that it is imperative for a developer to plan for charging capacity from the utility for 20-30% of the parking spaces with L2 type stations. (that is only for capacity. Actual deployment of stations is better served with a mix of L1s and L2 stations.) This will set up developments to maximize tenant satisfaction and charging capacity in the future.

The EV driver and their wants and needs
What does an EV owner and resident of a multifamily building want in terms of charging capacity, and how does this compare to what they need? Sure, we’ve seen the stations with a credit card reader that give a relatively quick charge, but are these types of stations the right ongoing solution for an EV driver living in a multifamily building? The reality is that these pay stations are best suited for someone in a bind who needs an emergency charge of their vehicle. Most often an EV driver needs a dedicated charging station located where they park frequently for long periods of time. This means that residents of a multifamily building are best served by a dedicated parking space and charger. It’s that simple. All the other chargers serve as backups or sources needed for taking longer trips.

What does an EV driver need for driving range and charging?
The average American drives less than 30 miles a day, and those living in a dense city in a multifamily building would likely drive even less. While charging capacity is most often quoted in how many hours are needed for a full charge, it is more practical to think about a charger’s capacity as the amount of range that can be added for each hour of charging. There are three levels of charging stations: A Level 1 (L1) station is a standard 120V plug, a Level 2 (L2) is a 240V plug (like those used for a dryer or oven), and a Level 3 (L3) is a 480V plug, which can be used for fast charging.

An L1 Station on average provides 4.5 miles of charge per hour, so a 12-hour charge gives approximately 54 miles of range. This is clearly sufficient charging capacity for the average American who drives less than 30 miles per day. This same person, after a work week of charging, would have an extra 120 miles of range ready to go for a weekend trip. An L2 Station typically charges 4 to 5x faster than an L1, so you can assume 20+ miles of range per hour of charging. While this station type clearly has a higher recharge capacity, cost and quantity of chargers also need to be considered when determining which system to provide. 

(Note: Tesla states that you can get 3 to 4 miles per hour of charging with an L1 charger. This level of charging capacity would produce between 36 to 48 miles per overnight charge.)

The most responsive charging system for cost and quantity
The most responsive charging system for a multifamily building is a combination of L1 and L2 chargers. Consider the cost dynamics: an L1 charger is $750 to install, whereas an L2 is $2,000 to $2,500. That pricing will vary by location and time, but the important takeaway is that an L2 charger can be 3x the cost of an L1. In other words, you can get three times the quantity of chargers providing L1 chargers. Additionally, an L2 charger uses 3 to 4x the power draw as an L1 charger, meaning that a garage with electrical gear capacity supporting charging for 20% of the spaces with L2 chargers could be serving 75% of the spaces with L1 chargers using that same capacity.

At this point, a spread of 70% L1 and 30% L2 chargers seems most optimal. This, however, might require your operations management team to sell the capability of L1s appropriately and help drivers understand the charging dynamics and range capacities. The L1s should be sold early and work to maintain some L2 availability for the EV driver that wants it. There are some drivers that will need the greater recharge range of the L2 charger or who demand it based on their perceptions of what they need. Obviously, the pricing strategy between the two can be adjusted to balance the uptake of these two different charging options.

L1 charging station installation and pricing specifics
L1 charging stations come in pairs. Each standard duplex plug has two outlets and should be mounted between two stalls to serve both. It is important to specify that each plug has a dedicated 20-amp GFIC circuit. That will provide for the maximum charge capacity for each of the L1 stations.

The approximate EV draw with a month of charging is $15 worth of electricity per the US Department of Energy. Therefore, it's recommended to price the L1 charger with a $20 to $30 premium over a standard space. The L2 station should be $25 to $35 above the L1.

Power management systems (PMS)
PMS allow a property owner to expand EV charging capacity using the power dedicated to L2 EV charging capacity. The result is the ability to provide 3 to 4x the charging capacity from an existing L2 supply circuit by spreading the charging through a series of “smart” chargers. This allows a developer to plan for an L2 charger at one space today and to create 3 to 4x additional stations off that same circuit in the future. Current PMS equipment is expensive, but the technology is developing, and the cost of the equipment will fall over time. To future-proof for this expandable network, the L2 station design should spread L2 stations with a spacing that allows 3-4 expandable stations in the direct vicinity of any given L2 space.

In summary, the first objective of a new development should be to get as much charging capacity from the utility as possible, with a target of 20% to 30% space capacity served by L2 charging. The second objective is to design a conduit distribution system that serves L1 and L2 chargers throughout a parking garage, with PMS that allows L2 locations to expand to 3 to 4 adjacent parking spaces in the future as the EV charging demand increases. The final objective is to trim out chargers for 30% of parking spaces for current use, which should likely meet demand until 2030. The conduit and charging capacity will by then be available to expand as needed to meet demand in the future.