Last update: Sep 16 2017
The charger is a Tiecheng ElCon PFC2500 (144V2K5W). With 240V input, the charger outputs up to 13A; with 120V, up to 7A. The ten profiles are set to allow adjusting the final voltage in 1V steps.
The proper shutoff voltage was determined by monitoring the individual cell voltages at the end of the charging process. No cell should exceed 3.5V.
The J1772 inlet is an ITT Cannon EVC-I-75A-600-P-5 purchased from Modular EV Power. I regret buying an inlet without a weather tight hinged cap. The wires on the inlet are quite large, enough for 75A. I used wire splicers and heat shrink tube from the hardware store to join the inlet to a 12 AWG extension cord that brings the power to the vicinity of the charger.
Mounting the inlet was straight forward. After removing the fuel filler pipe, I made some new holes and laid a piece of sheet metal under the plastic trim. The inlet is located at the bottom of the opening in the plastic trim, to provide space for the latch on the top of the J1772 connector.
The inlet cables are covered by the original fuel filler pipe protector. The protector originally mounted to the filler pipe itself. I fabricated two brackets with rivet nuts aligned for the protector's mounting holes. The inlet cables go through a plastic lined hole in the frame (whose original purpose I cannot remember), then up through the floor behind the rear seat.
The charger gets quite hot. To minimize heating of the cells located in the trunk, two 92mm 12V DC fans are mounted on the existing trunk vents, at the lower back of the rear quarter panels. The vents have flaps to allow air to exit, but not enter. Air enters the trunk through existing vents in the package shelf. The fans are powered by a 12V 6A DC power supply, model YU1206. This power supply is connected to the same AC source as the charger so that the fans blow whenever the car is plugged into a charging station. Like the charger, the 12V adapter accepts both 120VAC and 240VAC. The fans are Dynatron Top Motor DF129225BH, rated for 60CFM at 0.5A.
The charger has a status LED that blinks and changes color to indicates progress during charging. Since the charger is in the trunk, you cannot see the status LED without opening the trunk lid. An Arduino microcontroller circuit relays the status to a pair of LEDs mounted on the package shelf, visible when standing next to the inlet. The charger status LED is bi-color, green and red. I used two separate LEDs for the output rather than a bi-color LED because discreet LEDs are available with higher luminosity. The sun might shine in the window, so brightness is important. The output LEDs are mounted to a clip that slips onto a child seat attachment point.
The microcontroller is an Arduino Nano mounted in a plastic box just above the charger. Power for the microcontroller comes through an USB cable plugged into an USB power adapter, which is connected to the mains power coming to the charger. Thus, the circuit is only powered when the car is plugged into a charging station.
The controller determines the charger status LED state using a light sensor pointing at the LED. The light sensor is a Vishay TEPT4400 phototransistor. The microcontroller detects the color by the light level. The sensor detects the green color with a significantly lower output than for red.
Wiring diagram below. Source code is here.
At a car show, I opened the fuel filler lid to show the inlet. There were quite a few chuckles at the warning label that proclaimed PREMIUM UNLEADED FUEL ONLY. I never noticed this label myself, but it seemed everyone else did. I had a new label made to cover it up. Due to the economics of printing, I have quite a few extras. If you would like one, search eBay for EV Fuel Door Label.
When the car went through a car wash, the inlet filled with water. Unable to find a cap to purchase, I resorted to fabricating one from ABS plastic pipe, pipe fitting, and sheet. I used the retainer cord for a pre-2003 Subaru fuel cap (part 42032FC000). The cap is not water tight, but covers the inlet enough to keep water from running down into it. Next time, I'll buy an inlet with a built-in lid.