Anywhere, Anytime: The Flexibility of EV Charging


Written by Zachary Lee, Technical Lead for Fleet Charging Solutions at PowerFlex

The 3 Models of Electric Vehicle (EV) Chargers

The EV market is rapidly evolving, and along with it, customer behaviors and charging habits. There are 3 models of EV Chargers: home based, DC Fast Charging, and distributed.

At-home charging remains the most common model today, however more and more people are living in apartment buildings or homes without off-street parking with a need to charge their electric vehicles. Even when at-home charging is available, it cannot take advantage of abundant solar energy produced during the day.

Outside the home, DC Fast Charging is a popular choice, as seen by Tesla’s Supercharger network. Many envision that public DC Fast Charging will be the gas station of the future. In the gas station model, EVs charge infrequently but need a significant amount of energy quickly when they do charge. Many fast chargers can provide over 150 miles of range in under 30 minutes.

The third model is distributed whereby drivers plug in their vehicles at every opportunity –at home, at the office, at the supermarket, or the mall. Since most vehicles spend 95% of their time parked, they can be available to charge for a long time. We utilize Level-2 EVSE chargers for the distributed model, which can deliver around 20 miles of range per hour and are much cheaper than DC Fast Chargers.

There are many use cases where fast chargers are a great fit—for example, charging an EV during a road trip or getting some extra energy for an unexpected errand. However, for day-to-day charging, distributed charging is preferable for most drivers. This is because Level-2 charging can be healthier for vehicle’s battery. Also, the marginal time spent charging is nearly zero. Drivers simply plug in their vehicles and walk away. By enabling this distributed model, EVs are not only cheaper to operate than gas vehicles, they are more convenient as well.

Adaptive Load Management®: How We Can Make Every Parking Spot a Charging Station

The distributed model requires a broadly accessible charging infrastructure. To truly enable distributed charging, every parking space needs a charging port. This may seem like an impossible goal, but at PowerFlex, we are working to make this a reality. The biggest challenge to installing large numbers of charging ports is limited local electrical infrastructure and grid capacity. Using Adaptive Load Management (ALM), we can actively control how each EV charges to stay within the power grid’s limits and reduce the need for costly grid infrastructure upgrades.

With ALM and a plug in every spot, vehicles can stay plugged in all day. Intelligent software then decides when each vehicle should charge. This software can schedule charging to respond to time-varying prices or take advantage of cleaner energy periods (like midday solar). ALM software can also ensure that each vehicle always has enough battery charge to get to its next destination. Since vehicles plug in at each destination, they can always have a nearly full battery, providing an ancillary benefit: reducing the dreaded range anxiety.

Meeting the Needs of the Driver and the Grid

A concern about ALM is that it just means slower charging. But in a distributed model, this is offset by the fact that EVs rarely need a lot of energy quickly. When they do, the system can prioritize power to those EVs with urgent needs while slowing charging to more flexible EVs. By enabling a charging station in every space, ALM also ensures drivers will never be stuck waiting for a space to open or leave an important meeting to move their car so someone else can charge.

Even if most charging is done with a distributed model, there will still be a need for fast charging to support long-distance travel and urgent needs. ALM helps here as well. By co-locating fast chargers with Level-2s, we can throttle down the Level-2 chargers when the fast charger is active. This smooths out the demand on the grid and reduces the need for costly upgrades.

With advances in vehicle-to-infrastructure communication, such as ISO 15118, ALM can provide a seamless refueling experience. No more waiting in line for gas or a fast charger, no more worrying about idle fees or time limits, simply plug in your EV and get on with your day with the confidence of knowing you’ll have the power you need when you need it.