1. First Use
A. Connection:
The OBD cable's male plug is plugged into a mating female OBD socket (connector) that is located about 3 inches to the left of the LEAF's steering column, and about 4 or 5 inches forward "under" the dash ... above the driver's left shin.
Normally, you would follow the Test Procedure at the first-use plugging-in, to minimize the real possibility of damage to the car.
After that, plug in/out will probably be infrequent, except when testing a friend's car, or removing the SOC-Meter before visiting a Dealer for Service.
B. Initial Test (First Time Use):
You should follow the Test Procedure (see pdf at my web site) if the SOC-Meter has not been tested (or if it has been opened, dropped, modified, ... etc.), or if you are not sure.
WARNING: A short in anything connected to a car's OBD connector might disable/damage the car.
C. Display Baud Rate Setting
1. If the SOC-Meter was tested and configured properly when it was built, this setting has already been done. However, if the display has been replaced with a new unit (perhaps a different color), its default 9600 baud rate will show mostly "strange characters", and forcing (setting) the display's baud-rate to 57,600 will be necessary.
2. Setting Display Baud Rate at Power-On:
With the SOC-Meter connected to the LEAF's OBD port (to provide nominal 12v power),
a. set the Power Switch toggle to "straight out" (not Up, not Down) to turn the meter off.
b. Holding BOTH the Red and the Black push-buttons down,
c. switch the Power Switch UP (to Always-On) and wait for 3 seconds, and
d. then release both push-buttons.
e. The SOC-Meter should set the display's baud rate, display the meter's firmware number (like "F1.07"), and begin normal operation.
D. SOC-Meter Default Configuration:
1. Power Switch in Auto-ON mode (usually the toggle lever is Down). In this mode, the SOC meter should come "alive" when the LEAF is turned ON (as in Ready to drive), or when the LEAF is in ACC-2 Mode (2nd press of the car's ON button with foot NOT on the brake pedal).
2. CAN-Selector is set for EV-CAN (usually the toggle lever is down). The EV-CAN buss (when active) carries the message with a 10-bit value that we call "the raw SOC value". Although this value is NOT strictly a nice linear indicator of the car's remaining usable motive power, it appears to be related, going up to around 281 when you charge to 100%, and down to roughly 50 when the Low Battery Warning (LBW) occurs, roughly 25 when the Very Low Battery Warning (VLBW) occurs, and roughly 5 when Turtle Mode (TTM) occurs.
Note: It is BEST to plan to be recharging comfortably BEFORE TTM. The remaining useful energy MIGHT NOT be as much as this "SOC" number might lead you to believe.
WARNING: It appears that the LEAF will STOP "early" if needed to protect the "lowest" battery cell-pair. Normally (I believe), the LEAF WILL stop before zero-SOC is reached.
3. In this configuration, the SOC-Meter will automatically turn OFF when the LEAF is turned OFF, to avoid drawing extra current from the 12v battery. When ON, the Meter watches for the selected CAN buss (if any) to become active, displaying "----" as it waits. Then, a 0.0 (or just 0) is displayed until the first "SOC-message" is detected. The SOX-value is displayed in one of two formats: the "raw" value, and a "percentage" (raw 281 is currently used as 100%). The default is "percentage" format.