There are various external Electric Vehicle charging systems
available. Vehicle manufacturers build their EVs utilizing one of
two charging systems referred to as Inductive and Conductive
charging. EVs will only use one of these technologies because
they are incompatible and they employ different connectors.
Because of the fact that these two types of systems are
required by EVs on the road, providers of public EV charging (such as
the City of Pasadena) usually provide both types of chargers at any charging site.
In addition, the connector that is inserted in the vehicles
charging port for either type of charger is also somewhat unique.
PWP plans to continue to upgrade its EV charging infrastructure to support
new charging technologies.
Chargers available are UL Listed and typically provide either 120
VAC or 208/240 VAC single-phase in a safe manner. Few vehicles have integrated the
charging system onboard such that only a cable and plug is needed (i.e.
the GM EV1 onboard 120VAC extension cord). Semi-permanent or
portable external chargers are available but are difficult to locate and
require a unique UL Listing.
Fast or rapid chargersare
another type of charging system available. These systems require a
large consumption of power at typically 240 VAC or 480 VAC 3-phase.
Only certain vehicles can be charged this manner such as unique Ford
Rangers or Chevy S10 pickups since it requires specialized battery control
or cooling
technology. The Chrysler EPIC Minivan
EV allows for this type of rapid charging. Charging for this
vehicle from an
empty tank takes about 20 minutes (as opposed to 4-6 hours) and provides a
75% tank.
EV charging (inductive, conductive, or rapid) is performed at three
voltage and current levels. The levels are defined to meet the EV's
needs, to meet anticipated future technology needs, and to provide
compatibility with distribution systems. The NEC Handbook describes
the three charging levels. The following table summarizes the
electrical requirements of the three charging levels.
Voltage
(VAC)
Current
(Amps)
Power
(kVA)
Freq.
(Hz)
Phase
Standard
Outlet
Level 1
120
12
1.44
60
Single
NEMA 5-15R
Level 2
208/240
32
6.7/7.7
60
Single
SAE
J1772/3
Level 3
480
400
192
60
Three
N/A
Level 1 Charging
This type of charging uses a common 120 Volt, singe-phase outlet for a
three-prong grounded (NEMA 5-15R) connector with a ground-fault circuit
interrupt. Level 1 charging requires 8 to 14 hours to fully charge a
vehicle, depending upon EV and battery type. Sometimes this type of
charging provided with the vehicle as an alternate backup charging method
such as the GM EV1. Level 1 charging requires 12 Amps maximum
continuous current with 15 Amps (minimum) branch circuit protection.
Level 2 Charging
When using Level 2 charging, an EV can be charged in 4 to 6 hours,
depending on the EV battery type and capacity. This type of charging
requires 208-240 VAC single phase maximum nominal supply with 32 Amps
maximum continuous current with 40 Amps branch circuit protection.
Required safety features include grounding or electrical isolation,
personnel protection from shock, a no-load make/break interlock, and a
safety breakaway for the cable and connector.
Level 3 Charging
Commonly known as fast or rapid charging, this type of charging requires
high levels of voltage and current to replenish more than half of an EVs
battery capacity in as quickly as ten minutes. Level 3 chargers use
a 480 VAC, 400 Amp, three-phase electrical service and require the same
safety levels as Level 2.
Because of the fact that these two types of systems are
required by EVs on the road, providers of public EV charging (such as
the City of Pasadena) usually provide both types of chargers at any charging site.
In addition, the connector that is inserted in the vehicles
charging port for either type of charger is also somewhat unique.
PWP plans to continue to upgrade its EV charging infrastructure to support
new charging technologies.