Three basic types of charging stations exist today:

Level I charging typically uses a standard electrical outlet.  It uses a standard 3-prong plug with a ground-fault circuit interrupter located in the power supply cable within 12 inches of the plug.  Although 3-prong standard electrical outlets are present almost everywhere, Level I charging is not the preferred means of charging.  Depending on the battery type and capacity, it can take from 8-30 hours to fully recharge a battery.  In addition, several studies conclude that for some battery systems, Level I charging shortens battery life and reduces performance.

Level II charging employs a permanently wired and fastened station at a fixed location.  It requires ground fault protection for users, a no-load make/break interlock (which prevents vehicle startup while charging takes place), and a safety breakaway for the cable and connector.  Depending on the battery type and capacity, Level II can recharge and EV in 2-6 hours.

Level III is available and awaiting standardization of the connector by fall of 2009.  Fast-fill chargers are able to recharge 50% of an EV’s capacity in 25 min or less.  A level III system relies on an off-board charger that converts AC to DC.