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ZEVA

Electric Vehicle Management System v1.1: User Manual

Introduction

1. 

Developed to address the need to build safer, neater EV conversions, 
the  ZEVA  Electric Vehicle  Management  System  combines  several 
common functions required by EVs into one device:

• Battery Management System (BMS) Master Unit: Monitors your 
BMS cell modules and takes action to protect your battery pack.
• Staged Precharging: Most motor controllers require a precharge 
(soft-start)  system  to  slowly  charge  up  their  internal  capacitors 
before they are enabled.
• Contactor control: Many EVs run multiple contactors for redundant safety. 
This device manages auxillary contactors, which must be engaged when either driving 
or charging.
• Charge/drive interlock: Ensures that the vehicle cannot be driven while plugged in.
• Status light and buzzer: A multicolour LED indicates the vehicle status, and a buzzer 
gives audible warning of any errors detected.

Installation

2. 

The EVMS should be mounted securely to the vehicle using screws through 
the four 5mm holes on the case flanges.

There are 20 I/O terminals to connect for full functionality. A recommended 
wiring diagram is overleaf. The use of forked crimp terminals is recommended 
for  the  most  reliable  connections  to  the  EVMSs.  Wire  gauge  used  for 
most  connections  should  be  around  18-20  AWG,  to  ensure  reasonable 
mechanical strength. Small multicore cable is acceptable for the LED and 
buzzer wiring harness.

Status LED and Buzzer

3. 

The status LED may display the following codes:

Blue, blinking: Vehicle idle (sleep)

• 

Blue: Charging enabled

• 

Green, flashing: Precharging

• 

Green: Drive enabled

• 

Red: BMS error

• 

Red, flashing: Precharge error

• 

Green/red flashing: BMS shut down drive

• 

Blue/red flashing: BMS shut down charger

• 
The buzzer will sound continuously on BMS error, or intermittently 
on precharge error.

Zero Emission Vehicles Australia 

 

 

           http://ww.zeva.com.au

Description of I/O Terminals:

5. 

+12V: 

• 

A  permanent  +12V  supply  (9-16V  range), 

in  series  with  any  emergency  stop  switches  to  ensure 
everything downstream from the EVMS (charge and drive 
systems) switch off immediately in an emergency.

Ground: 

• 

Connect this to chassis ground in your vehicle 

(not traction circuit negative)

Key In: 

• 

Should see +12V when they key is turned on, 

ground or floating otherwise.

Chg Sense: 

• 

This terminal should be pulled to ground 

whenever  you  wish  to  charge. Typically  achieved  with 
either a normally-open switch on your charge door, or an 
AC relay that closes when the charge cable is plugged in.

BMS  In: 

• 

This  terminal  should  be  pulled  to  ground 

whenever  there  is  no  error  reported  from  the  BMS 
modules. If using a one-wire BMS system, connect one end of your cell module daisy 
chain to ground and the other end to this terminal.

Status RGB: 

• 

Outputs for Red, Green and Blue pins on the multicolour status LED 

(should be installed in the vehicle cabin).

Buzzer: 

• 

Connect this to the positive terminal on the included piezo buzzer (should 

be installed in the vehicle cabin).

Ground: 

• 

May be used as the ground connection for both the status LED and buzzer.

Prech A & B: 

• 

Connect these to either side of your main contactor. These The polarity 

is important: A should be on the battery side, B should be on the controller side.

Drive  Enable: 

• 

Connections  to  the  drive  enable  relay,  which  will  close  when  the 

vehicle is allowed to drive. Best used to switch in either the controller enable or throttle 
signal to controller.

Charge Enable: 

• 

Connections to the charge enable relay, which will close when the 

vehicle may be charged. These internal relays rated to 10A current at either 250VAC or 
28VDC. They are not suitable for switching typical traction pack DC voltages, or high 
charge currents. Unless using a low current charger, in most cases you will need to use 
the internal relay to switch an external power relay to control AC power to the charger.

Main Ctr: 

• 

This terminal goes to the positive connection on your main contactor.

Ground: 

• 

May be used for the negative connection on your main contactor.

Aux Ctr: 

• 

This terminal goes to the positive connection on your auxillary contactor(s).

Ground: 

• 

May be used for the negative connection on your auxillary contactor(s).

 

6. 

Brief Specifications

Power supply: 9-16VDC (~20mA idle, 5A max)

• 

Suitable for traction packs: 12-160VDC 

• 

Dimensions: 150x100x50mm 

• 

Casing: Fully enclosed die cast aluminium, weatherproof to IP65 

• 

Internally fused, reverse voltage and over-voltage protected 

• 

The ZEVA EV Management System is proudly 
designed and manufactured in Australia.

Zero Emission Vehicles Australia 

 

 

           http://ww.zeva.com.au

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