WatchMonCORE and Expansion Board 3 Hardware Guide and Pin Assignment

WatchMonCORE Replaces WatchMon4

Introducing the next generation of WatchMonCORE supervisor. We have made a new model, a stronger WM4...a better 4... now shall be named WatchMonCORE This revamp is taking the lessons we have learned from WM4 and building on this proven platform introduce a few new features.
Moving forward this will be the core building block that additional components will link to this supervisor in the future. 

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  • BMS to suit LiFePO4, Lithium-Ion or custom chemistry
  • User configurable parameters and control logic
  • Configurable 30vdc 5A relay (i.e. remote circuit breaker trip, contactor or fan)
  • Additional inputs / outputs via Expansion Board purchased separately 
  • Compatible with all Expansion Board (Series 1, 2, or 3
  • Clock with backup battery data logging of key metrics for 10 years 
  • Firmware upgrades via USB 
  • 4 stage display of State of Charge (SoC%
  • External ambient temperature sensor 
  • Easy to use pluggable screw-terminal connectors 
  • With distributed cell monitors capable of 28 Ah / day balancing adjustment for each cell 
  • Link to ShuntMon with 500A or 1000A power rating
  • Compatible with MultiMon (MM8)

Remote Communication

  • WiFi connectivity (normal, disabled, or read only
  • CANbus Opto-Insulated to remote Charger / Inverter equipment 
  • Future feature to connecting to Cloud Portal via MQTT (secure link)


  • Easier to use layout than previous models
  • Bigger DC-DC (6W) supporting 8-65V supply
  • Cell Monitor port (aka CMU) now with its own external fully isolated communication module named "IsoMon3" that can link to LongMon, BlockMon and LeafMon
  • CMU and Shunt serial ports have a different number of pins to avoid confusion
  • New on-board Relay (30vdc 5a relay) making it easier for DIY wiring

Optional Expansion Board (Series 3) Details

  • 3 x Mechanical 30Vdc 5A relay outputs
  • 3 x Solid state relay SSR 65vdc 5A isolated modules outputs
  • 2 x Isolated inputs 5-65vdc sensor channel
  • 2 x ADC 0-5vdc (future development option)
  • 1 x RS485 Serial port (future development option)
  • 1 x External Addressable LED (future development option)
  • Compatible with all supervisors


  • WatchMonCORE        Length 107 mm x Width 55 mm
  • Expansion Board-E3 Length 107 mm x Width 55 mm


WatchMonCORE requires the Latest release of WatchMon Toolkit (minimum of 2.16.4)

Connecting LongMons to CMU Serial Port

  • Best to number the first cells from Negative in increasing order
  • Hi speed CMU serial  with the isolation moved to separate IsoMon3 for single cell monitors      (i.e. LongMon, BlockMon and LeafMon)
  • CMUConnect and IsoMon3 are NOT interchangeable 
  • WatchMonCORE requires a IsoMon3, the use of a CMUConnect will damage the WatchMonCORE product

Follow the commission and trouble shooting guides to install:-

Connecting to ShuntMon

CMU and Shunt serial ports have a different number of pins to avoid damage / confusion

Connecting to Inverter / Charger using CANbus

List of available Inverter / Charging equipment can be found from the following link

Powering WatchMonCORE supply

For High Voltage battery pack systems best to adopt a Fully isolated DC-DC to provide a supply voltage of either 12v or 24v depending on application.

  • Built-in 8v to 65v DC-DC supply (non isolated)
  • Consumes ~1.7W with WiFi enabled (typical 48v battery budget 1Ah / day)

Controlling a FAN from WatchMonCORE Onboard Relay

  • Mechanical relay Max 30Vdc 5A
  • Labelled as Relay A
  • User defined function

Controlling a FAN from WatchMonCORE, Expansion Board-E3 using a Relay

  • Up to 3 Mechanical relay Max 30Vdc 5A
  • Labelled as Relay 1, 2, and 3
  • User defined function

Controlling a FAN from WatchMonCORE, Expansion Board-E3 using a Solid State Relay SSR

  • Up to 3 Solid State Relay SSR  3 to 65Vdc 5A (1 way disconnect)
  • Labelled as SSR 5, 6, and 7
  • User defined function(s)

Sensing Switch Signal from WatchMonCORE, Expansion Board-E3 using a Opto-Isolated Input

VIDEO Helicopter Preview of Product with Optional    Expansion Board-E3

VIDEO Overview and Unboxing

VIDEO Step by Step Supervisor Installation with LongMons

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