Oilpan4 said:
Is this an internal GFIC? Or external like installed in the breaker panel?
It's the wire-lead current transformer inside the Juicebox. The original Juicebox (sold as a kit) has a procedure for adjusting this (you push/pull the A/C leads where they pass through the CT core, until the number of millivolts returned by the CT's secondary is minimized; then glue the wires in place with electrician's silicone).
To measure the CFCI output, you measure the millivolts between Arduino pin A1 and ground. In my case, I got a reading of "355 mV" at 6A of charging current, which doesn't seem to match the manual.
*** UPDATE, I got the text output from the Juicebox's Arduino microcontroller board ***
I connected a laptop with Arduino IDE to the Juicebox controller, and now I can see that it is throwing Failed Diode Check errors:
JuiceBox JuiceBox Classic:: HW:081401:: FW:100107:: Sup FW:04:: JNet Ver:07
Jfirmware MFG Date:Oct 25 2018:: Time:13:44:19
NFO:GFI Circuit Line Voltage Sensed at 275
0814011001070449459318990402
BG,103
iode Check Fail:
0814011001070449459318990402
BG,603:CLR Diode Check Fail:
0814011001070449459318990402
BG,103
iode Check Fail:
0814011001070449459318990402
BG,603:CLR Diode Check Fail:
...
(for posterity: I connected an Arduino FTDI's RX pin to juicebox TX pin, FTDI TX to Juicebox RX, ground to ground; and FTDI DTR to juicebox ground. The FTDI's CTS and +5V were left unconnected. I set the Serial Monitor app in Arduino IDE to "9600,8,N,1")
After seeing this Diode Check Fail error, I checked resistance from the Leaf's J1772 pilot pin to ground pin, and vice-versa. My MS8239D multimeter read 12 mega-ohms from pilot to ground, and infinite from ground to pilot. A second (even cheaper) multimeter read 3 meg-ohms pilot to ground and infinite from ground to pilot. This is odd, since YouTube claims that I should be reading K-ohms from pilot to ground, and Mega-ohms from ground to pilot ( https://www.youtube.com/watch?v=5R4dGg8nIUs ). But I checked both meters using a pile of 10K resistors, and on every resistor, both meters agreed to within 0.2%. I have no idea why they read an order-of-magnitude different from each other when checking for a working diode on the Leaf.
I've tested L2 charging the Leaf on public chargers, and it worked fine on Chargepoint, Siemens and Aerovironment. So I think the diode is fine. My takeaway is: don't expect that can reproduce the readings in that YouTube video for testing the Leaf diode.