Photos courtesy of Oregondot (Flickr)
The decreasing charge rate is not visible to the driver...It would help to have both the car and the station present the driver with this information average charge rate was just 6.6 kW, the same as a 2013 LEAF with a 6.6 kW on-board charger would pull from a Level 2 station. So, for a 3.3 kW LEAF driver seeking a full charge, a DC fast charge station offers no advantage over a Level 2 station above 85% state of charge. For a 6.6 kW LEAF owner, the advantage ends at around 75%. Going up to the 85% mark makes sense even for a 6.6 kW LEAF owner, but continuing to charge all the way to the top makes little sense if Level 2 charging is also available. The decreasing charge rate is not visible to the driver. Neither the LEAF, the Blink DC station nor the Aerovironment DC station (also common in the Northwest) shows the charge rate. It would help to have both the car
and the station present the driver with this information. On the other hand, there are circumstances when a driver may need to get a full charge from a fast charge station, for example along a highway where a charge is needed to get to the next station with a comfortable buffer. In such cases, assuming there’s no opportunity to conveniently switch to a Level 2 station, charging until completely full is reasonable and justified.
Billing model options and efficient use In light of what we want to accomplish with public charging infrastructure and how DC fast charging actually works, let’s examine the most obvious candidates for billing models.