ELECTRIC VEHICLE MANAGEMENT SYSTEM V3
ZERO EMISSION VEHICLES AUSTRALIA
Description of Connections
Terminal name
I/O
Description
+12VDC
Input
To 12V battery positive (permanent supply, not key
switched). 8-16V maximum range.
Ground
Input
To vehicle chassis or 12V battery negative
Key In
Input
To key signal, should be +12V when key is turned on
Charge Sense
Input
Connect to your charge detection switch, such as a fuel
door switch or 240V detect relay/circuit. Should connect
to ground/chassis when the switch is on.
MPI
Input
Multi-Purpose Input, assignable to a range of additional
functions.
Main Ctr Cathode
Input
Connect to the power terminal on the motor controller
side (i.e output / cathode) of your main contactor
HV+
Input
Connect to the most positive potential of your battery, or
the input / anode of your main contactor.
HV-
Input
Connect to the most negative potential of your battery.
Main Ctr
Output
Connect to the positive wire of your main contactor coil.
The contactor coil negative wire should be connected to
ground/chassis.
Aux Ctr
Output
Connect to the positive wire of your auxiliary/secondary
contactor(s). The coil negative wire should be connected
to ground/chassis.
Charge Enable
Output
Connect to the +12 terminal of a relay which can enable
your charger (usually turning the AC supply on, or charge
enable input pins supported by some chargers). The other
side of the relay should be connected to ground/chassis.
Ground
A spare ground connection point, often used as a ground
for contactor wiring.
MPO1
Output
Multi-Purpose Outputs 1 and 2, assignable to a range
of additional functions. Please refer to section Multi-
Purpose Input and Outputs for more information.
MPO2
Output
Fuel Gauge
Output
To the fuel gauge input connection on your vehicle’s
OEM instrument cluster (or aftermarket fuel gauge).
Tach Gauge
Output
To the tachometer input connection on your vehicle’s
OEM instrument cluster (or aftermarket tachometer).
CAN Bus Wiring
The EVMS uses CAN bus to communicate with other devices in the vehicle such as BMS
modules, EVMS Monitor, CAN current sensor, TC Chargers and ZEVA motor controllers.
Note that every manufacturer tends to implement their own protocol on CAN bus so the
EVMS will not be able to communicate with CAN-enabled devices from other manufacturers
(other than TC Chargers). Normally it is best for ZEVA devices to use their own dedicated
CAN bus rather than share an existing CAN bus with other devices, to avoid the possibility
of bandwidth limitations and ID conflicts.
The EVMS itself has two CAN bus connectors, joined to the same bus internally, which
can be connected in either order in any location along the CAN bus. The EVMS3 and
most associated devices use Molex Eurostyle pluggable screw terminals for the CAN bus.
Connector wiring is shown in the diagram below:
Shield
Ground
CAN L
CAN H
12VDC
Note that while connectors into most devices go screw side
up, due to the orientation of the internal circuit board in the
EVMS3, its CAN plugs are inserted with screw side down.
CAN buses work best when wired as a single daisy chain of devices, with 120ohm termination
resistors at each end to prevent signal reflection. Most ZEVA CAN-enabled devices have dual
CAN plugs for easy daisy-chaining. The order of devices is unimportant - usually the shortest
path between devices is best. The EVMS Monitor is most commonly installed at one end of
the CAN bus so only has a single CAN port, and a built-in internal termination resistor. The
monitor may be installed in the middle of a CAN bus by creating a short Y-branch off the bus
to the Monitor’s CAN plug, and removing the small pin jumper on the right of the CAN plug
to disable the internal termination resistor.
For the sake of noise immunity, CAN buses typically use twisted pair cable. Since electric
vehicles can involve high electromagnetic interference (EMI) from the traction circuit, we
recommend using shielded twisted pair wire for maximum noise immunity. Very short spans
are usually OK with untwisted and/or unshielded cable.
CAN buses and the attached devices do consume some power (an EVMS with a few BMS
modules and an EVMS Monitor will use in the order of 200mA), so in order to reduce
quiescent drain on the auxiliary battery, the EVMS will normally switch off the CAN bus after
a configurable number of minutes in Idle state (i.e neither driving, charging, or in setup) to
save power. Setup mode can only be entered from Idle state, so needs to be done during the
time window before the CAN bus powers down. The sleep delay is configurable in settings,
and sleep can be disabled altogether.
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