We decided to have an EV, Plug-in Auto Show, Saturday in honor of Earth Day. We had a Tesla, two BMW i3-REx, and a Prius Prime BUT it was our first attempt. I presented the program. This chart comes from the USA Energy Information Administration, Dec 2017 for Alabama. Understand I have no problem with burning coal to make electricity. Rather I think it is wrong to burn coal inefficiently. A simple formula show coals can be burned more efficiently: The J1772 connector is an SAE standard: In the USA there are two types of power distribution. Split phase is what is found in the home, neutral is center tapped and two legs. Commercial power can be three phase: Between L1 and L2 in the home, the unloaded voltage will be 120VAC to neutral and between L1-L2, 240 VAC. In three phase, each leg is 120VAC relative to neutral, a white wire, and due to the phase angle, 208 VAC between any pair of legs. The pilot signal is how the EVSE tells the car the maximum current, regardless of voltage. At the same time, the car signals to the EVSE that it is there, received the maximum allowed current, and time to enable power to the J1772: At -12V between the pilot and ground, the EVSE is broken. It may take 30 seconds before the two drops the link with an error. If someone walks away too soon, they won't see the error show but they will find there was no charge. There is a 1k ohm resistor on the pilot line in the EVSE. The a car plugs in, it has a resistor that reduces the voltage to 9 V. Then the EVSE can signal the maximum allowed current by a pulse width modulated, 1 kHz signal. In the example, 75%. Using the chart it corresponds to ~45A. Then the car adds another resistor to lower the voltage to 6V so the EVSE will connect the power pins to the grid. If the car needs a cools environment, it can lower to 3V so the EVSE garage can lower the ambient temperature. One issue is many do not know how to answer the question of how much does it cost to drive. The USA EPA provides kWh and gallons per 100 miles. These can quickly give a credible metric of EV versus gas miles, more than 2-to-1, gas over electric: Now a replacement EVSE can come in different makes and models: The cheapest is a straight replacement. Although tempting, a dual voltage EVS at 16 A can not be used in the older NEMA 5-15 plug. A better but more expensive solution is dual voltage and multiple current. An expensive but better approach is a home EVSE with management: The EVSE communicates with a server that the user can access and manage with either a personal computer or cell phone. When trying to get a commercial installation, the goal is to make a fair trade. Provide 'free' electricity to pay for the trip down: Here is an example of typical, PC based management including monthly summary, daily summary, and down to individual charge sessions: It can also provide performance graphs fo charge over time: Here we see the smart phone App of the same data. NOTE: the internal voltage is shown higher than 208VAC. I don't know if it is some local power or more likely, internal voltage measurement error. Bob Wilson ps. Fuel cell advocates were absent.