How to Control Victron equipment using a GX gateway to the WatchMon

Here are the steps to configure the Victron Venus GX.
The same methods can be used to any of the other GX device variants to the WatchMon Supervisor.

CAUTION:  Example below has values shown for a demo LiFePO4 cell pack, ensure that you adopt values suitable to your application and comply with the battery suppliers recommendation. 

Step 1 - Install communication cable to CAN port on WatchMon.

For newer WatchMon (Note 120 Ohm resistor shares CANbus High and CANbus Low)

For older WatchMon with 4 pin CAN see below

Step 2 - Install communication cable to Victron Venus can2 socket (extract from manual)

Custom Cable pinout for Venus GX



Supply negative / ground



CAN low



CAN high

Function Venus GX (canbus2) Watchmon

For reference here’s an ethernet plug diagram. Be aware that some ethernet cables may vary.

To make up the custom ethernet cable for the Venus properly you should use a proper crimper and fresh RJ45 male connectors.

Step 3 - Navigate to Hardware, then Integration tab.

Step 4 - Select Canbus protocol to "Victron Colour Control GX" and Save.

Step 5 - Navigate to Control Logic, then Charging tab.

Step 6 - Adjust the charging control logic to suit the application.


  • Low power must be enabled.
  • Cell Hi Cut out should be above the CellMon bypass voltage threshold as a safe guard target.
  • Low power current should suit the bypass capability of CellMon.
  • When the bypass current is above Initial will trigger the system to low power.
  • When the bypass current for all cellmons is above Final the system will complete charging cycle.

Step 7 - Navigate to Hardware, then CellMon tab.

Step 8 - Adjust the CellMon bypass voltage to suit the application if required.  

Note:  We have profiles such as Li Ion Long life that give suggested values, If batt Type is changed to Custom this can be adjusted

Note: Make sure to "Device Sync" the changes to the CellMons.

Step 9 - Navigate to Control Logic, then Remote tab.

Step 10 - Adjust the remote charging target to suit the application.


  • Scaling must be 10 for both voltage and current.
  • Low power must be enabled on charging tab.
  • Low power current should suit the bypass capability of CellMon.
  • Charger voltage target needs to be sufficient for all cells to reach bypass threshold.

Step 11 - Adjust the remote discharging targets to suit the application.


  • Scaling must be 10 for both voltage and current.
  • Do not run low power mode on discharging tab.
  • Control logic discharge voltage cut out should match the remote target.

Step 12 - Navigate to Telemetry, then Live Stats to Observe System Operation.

Step 13 - Within Victron Software - VEConfigure Settings

13.1 General tab
  1. Check “ Enable battery monitor

  2. Enter the battery capacity in Amp Hours ( i.e. 120.0 Ah)

  3. The other parameters ( “State of charge when bulk finished” and “Charge efficiency”) can be left to their default setting. They are not used in this setup.

13.2 Charger tab

Battery type


Charge curve


Absorption voltage

60.75 V

Float voltage

60.00 V

Absorption time

1 Hr

Parameter Setting

Note: make sure to double check the float voltage after completing Assistants, and if necessary set it back to 60.00 V.

This needs to be adjusted to match the BMS operating targets

13.3 ESS Assistant

Select the fourth battery type:


  1. Do not change the dynamic cut-off values, they have already been set correctly after selecting the lithium battery type.

  2. Sustain voltage: 50V

  3. Same for the restart offset: do not change that.

14. Venus device Configuration

  • Select the  CAN-bus BMS (500 kbits/s) CAN-profile in the Venus device. Menu path:  Settings → Services → CAN-profile

  • Note that this changes the function of a VE.Can port: it is not possible to connect both VE.Can products and a BMS battery together on a Color Control GX. Is is possible on the Venus GX 

  • Select CAN-bus BMS (500 kbit/s)
  • After properly wiring and setting up, the BMS the ESS will be visible as a battery in the device list:

  • The parameters option within the battery page shows the actual battery charge and discharge limits:

Additional useful screens to monitor:

  • Node Chart
  • Charging logic control 
  • Remote logic control
  • Live Statistics telemetry
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