August 18, 2023

What are dual EV chargers?

Woman charging a Hyundai Ioniq 5 next to a Tesla Model Y using an Enel X Way JuicePedestal

Whether they’re charging a proprietary electric vehicle (EV) fleet or offering EV public charging, organizations offering EV charging are all faced with the same dilemmas: how many chargers are needed, and when should they be installed. 


Underestimating the number of chargers needed has its consequences:


  • if an organization is using public EV charging to attract customers, increase dwell time in their location or offering fee-based public EV charging, chargers that get a reputation for being always occupied will drive business elsewhere
  • if an organization is charging their EV fleet, insufficient charging connectors will lead to vehicle downtime and begin to cut into revenue or require fleet vehicles to pay for charging elsewhere, increasing operational costs


While the way to avoid either consequence is of course to increase charger availability, the infrastructure costs of doing so can be prohibitively expensive. Especially if part of those costs are doing work that’s already been done: digging, trenching, cutting and covering conduit. There is also the danger of overestimating demand and installing charging infrastructure that mostly sits idle, putting an unnecessary Capex burden on organizations.


By drastically reducing the amount of electrical infrastructure required to install a second EV charger where one already is, dual EV chargers change this equation for organizations.


How dual EV chargers work

In short, dual EV chargers are two charge connectors that safely share a single electrical circuit. While it seems quite simple, it’s actually a fairly rare thing to find among electric vehicle supply equipment (EVSE) on the market.


Almost all chargers list either a kW maximum, an amperage maximum (e.g. the JuiceBox Pro 40) or both. Without getting into the weeds of watts vs. volts vs. amps, both represent the limit of electricity a charger can move from an electrical source to an EV.


The electrical infrastructure running from electricity source to a building’s electrical panel, and from panel to EV charger also have limits. No building can pull an unlimited amount of power from the grid, and if a building is generating its own power, it can’t use more than it makes.


If two identical standard EV chargers were connected to the same source, and both were plugged into EVs at the same time, they would both try to pull as much electricity as they could. If that pull represented more than your electrical load limit, this would at best lead to circuit breakers tripping and the circuit shutting off, at worst electrical overload and equipment getting dangerously hot. In either case, it’s not a tenable way to charge two EVs.


Here’s a simplified diagram to illustrate the limitations:

Graph displaying amperages of multiple EV chargers connected to the same panel

Rather than require double the amperage, dual chargers share the same amperage cap and actively communicate with each other. When both chargers are in use at once, they split the available amperage equally  up to their own caps (assuming both EVs can accept that much charge), avoiding overload.


When one vehicle is unplugged, or finished charging, the other charger uses as much amperage as it can. This load balancing is especially helpful for EV fleet depots, allowing organizations to install enough EVSE to charge their full fleet on half the electrical capacity otherwise required.


Comparing the costs of installing a second charger without dual charging

To duplicate the electrical capacity of a Level 2 charger (which is at least 240V), electrical panels often require pricy upgrades, then there’s the cost of conduit and wire to get from the panel to the plug location, the cost of a second 240V receptacle, the time and cost of any re-trenching, cutting and whatever else may required to lay the conduit.  Dual chargers eliminate the need for all of that, requiring only a junction (and second 240V receptacle if the charger is plug-in).


The two types of dual charger setups

There are two dual charger setups organizations can utilize to avoid adding expensive electrical infrastructure:


Dual charging stations

Dual charging stations, like Enel X Way JuicePump DC fast chargers, have two charging connectors attached to separate cables, both running to the same console. When two EVs are plugged in at the same time, they automatically split amperage evenly. All three dual chargers can charge one vehicle at the chargers’ max amperage (e.g. 50A), or two simultaneously at half the chargers’ max each (e.g. 25A).


Two chargers with load-sharing capabilities

WiFi-equipped smart chargers like the JuiceBox Pro 40 can connect to the same circuit, either hardwired or through separate plugs, sharing the available amperage just like a dual charging station does.


Dual JuiceBox Pros can be purchased and mounted on a JuicePedestal, which comes pre-assembled and ready to be hardwired to the electrical line. When an Enel X Way credit card reader (CCR) is added to it, the whole package is California Type Evaluation Program (CTEP) compliance. That gives your customers confidence that they’re getting exactly the amount of charge displayed on the charger, just like at a gas pump.

JuiceBox Pro 40s can also be purchased separately and either wall-mounted or attached to a JuiceStand Pro, the perfect solution for charging in open areas like parking lots.


Consider adding dual chargers to your site

Where superfast charging is not necessary, dual EV chargers should be the go-to for both fleet charging and fee-based charging. They significantly lower the cost of adding commercial EVSE to a site, take far less time to add than a standard EV charger and can integrate seamlessly into most parking setups while saving you space.

See how to JuiceBox Pro 40's dual charging functionality works for you