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Battery Monitor Connection Instructions:

Connections to 12-volt accessory power:

The battery monitor and display are powered from the accessory 12-volt
supply in your vehicle.  This supply is isolated from the main
battery pack in most vehicles and the monitor preserves this isolation
with an internal DC-DC converter.  Note that both the measurement
and display metal boxes are connected to the 12-volt system ground. 
They should never come into contact with any of the main battery terminals
or the positive terminal of the 12-volt system.

The 12-volt power to the meter is supplied to the un-marked red and
black wires on the 24-pin AMP circular plastic connector. (red is positive
and black is negative)  Be careful to ONLY connect these wires
to 12-volts and NOT to any of the main battery wires.  This will
damage or destroy the unit.

The monitor will still work in vehicles without an isolated 12-volt
system but be aware that the metal cases are connected to whatever 12-volt
ground you supply to the red and black wires.

Connections to the main battery pack:

The 24-pin AMP circular plastic connector houses
the connections to each of the batteries in the main pack.  Wire
#0 is connected to the traction battery ground, wire #1 is connected
to the positive terminal of the first battery, wire #2 is connected
to the positive terminal of the second battery, and so on.  (See
diagram below)

There MUST be a small-value fuse in series
with each battery connection as close to the battery as possible
(preferably smaller than a 1A fuse closer than 1 foot from each battery
terminal.)  Fuses are extremely important and the warranty will
be void if the unit is used without proper fusing in place.  Plastic
in-line fuse holders are ideal for this purpose.

Connecting the wires:

Care should be taken in connecting the wire
pigtails into your vehicle.  Be sure to insulate the connections
well to prevent any shorts or contact to the vehicle frame.  Also
be sure that all of the connections are tight or else erratic voltage
readings may result.

Display Connector:

The graphical display receives data and power
through the standard DB9 connector.  A straight-through cable must
be used between the two boxes.  The communication is via standard
RS-232 at 19.2 kBaud.  5-volt power is supplied to the display
box on pin 9 and the RS-232 data is present on pin 3.  Pin 5 is
ground.  Do not attempt to power any other devices from this 5-volt
supply!  It is only designed to interface with the display unit.