DataHub > Services > NMEA > DC Battery and Alternator monitoring page
The DataHub uses the Services > NMEA > DC page to display battery and alternator information received from the boat’s NMEA 2000 network.
The DataHub does not measure battery voltage, current or charge state itself. Values are measured or calculated by equipment such as a battery monitor, shunt, BMS, Victron Cerbo GX, or a compatible alternator regulator, and then transmitted to DataHub Pro via N2K.
The DataHub supports two levels of battery and alternator information:
Enhanced Victron support for a Victron Cerbo GX and connected Victron SmartShunt, battery monitor or BMS.
General NMEA 2000 support for other compatible battery monitors and alternator regulators.
What can the DataHub display?
Information | Victron Cerbo GX local page | Other compatible NMEA 2000 source | Victron battery data on GPS Tracking |
Name | Yes | No | No |
Manufacturer | Yes | Yes | No |
Model | Yes | Yes | No |
Version | Yes | Yes | No |
DC instance | Yes | Yes | Grouped by battery instance |
Voltage | Yes | Yes | Yes |
Current | Yes | Yes | Yes |
Temperature | Yes | Yes | Yes |
State of Charge | Yes | Yes | Yes |
State of Health | Yes | Yes | Yes |
Time Remaining | Yes | No | No |
Ripple Voltage | Yes | No | No |
Amp Hours Used | Yes | No | No |
A value displays as NA when the source equipment does not provide that measurement.
Enhanced Victron Cerbo GX support
A Victron Cerbo GX can make battery information from connected Victron equipment available to the DataHub through NMEA 2000.
How it works:
A SmartShunt, BMS or battery monitor measures or calculates the battery information.
The Victron Cerbo GX receives the information from the connected Victron equipment.
The Cerbo GX publishes the supported information to NMEA 2000.
DataHub identifies the Victron source and displays the extended field set.
DataHub can upload selected battery fields to GPS Tracking.
For Victron Cerbo GX and any compatible device, the DataHub > Services > NMEA > DC page can display:
Name
Manufacturer
Model
Version
Instance
Voltage
Current
Temperature
State of Charge (SoC %)
State of Health (SoH %)
Time Remaining (Victron only, not shown on GPS tracking)
Ripple Voltage (Victron only, not shown on GPS tracking)
Amp Hours Used (Victron only, not shown on GPS tracking)
The available fields depend on what the SmartShunt, BMS, battery monitor and Cerbo GX provide. For example, one battery instance may include State of Charge and Temperature while another provides only Voltage and Current.
The DataHub does not calculate State of Charge, State of Health or Time Remaining from voltage. These values come from the connected Victron equipment.
General NMEA 2000 battery and alternator support
For other compatible NMEA 2000 devices, when supplied, DataHub can display:
Manufacturer
Model
Version
DC instance
Voltage
Current
Temperature
State of Charge (SoC %)
State of Health (SoH %)
The source must provide sufficient NMEA 2000 information for DataHub Pro to identify it as a battery or alternator.
Additional fields, such as State of Charge, may appear in the source’s NMEA 2000 data and will be displayed if the DataHub Pro can interpret the manufacturer's PGN.
For detailed compatibility and PGN requirements, see DataHub Pro: NMEA DC Status Compatibility and Troubleshooting.
Before you start
You need:
A DataHub connected to the boat’s NMEA 2000 network.
A battery monitor, shunt, BMS, gateway or alternator regulator that supplies compatible NMEA 2000 information.
The source equipment is powered and showing valid information on its own interface if it has one.
Firmware 4.54 or later for the enhanced Victron behaviour described in this article.
To view it on your GPS Tracking page, you must have set up a tracking page and have registered your DataHub Pro serial number to update it.
View battery and alternator information on board
Connect your phone, tablet or computer to DataHub Wi-Fi or a DataHub LAN port.
Open Safari or Chrome.
Go to 10.10.10.1.
Log in using your DataHub Pro administrator credentials.
Under Services, select NMEA.
Select DC from the top menu.
Each battery or alternator appears as a separate source or instance. Battery and alternator values update approximately every 10 seconds.
What do the values visible on the DataHub > Services > NMEA > DC page mean?
Data Field | Definition |
Voltage | The voltage supplied by the battery monitor, BMS or alternator regulator. |
Current | The Current flowing on that circuit, as is usually measured with a shunt.
|
Temperature | In degrees Celsius (C°). This data is supplied by a connected sensor. NA usually means no compatible temperature value is being transmitted. |
State of Charge | The source equipment’s estimate of how much usable battery capacity remains. State of Charge is not calculated by the DataHub. |
State of Health | A health or capacity estimate supplied by the connected battery equipment. Not every SmartShunt, BMS or battery system calculates or transmits State of Health. |
Time Remaining | An estimate supplied by the source equipment based on its current load, battery capacity and calculation method. |
Ripple Voltage | A voltage-ripple measurement supplied by the source equipment. |
Amp Hours Used | The amp-hour value supplied through the supported Victron integration. The interpretation and availability of this field depend on the connected Victron equipment. |
How to use the DataHub to view battery information away from the boat
Example GPS Tracking page > Boat Data > More Data > scroll down to Battery Instances
Remote battery information is available through DataHub GPS Tracking.
Open your boat’s PredictWind GPS Tracking page.
Select Boat Data.
Select More.
Scroll to the battery-instance sections.
For a supported Victron Cerbo GX installation, GPS Tracking can display:
Battery Voltage
Battery Current
State of Charge
State of Health
Battery Temperature
Each battery instance may supply a different field set.
A dash means no value was included for that field in the uploaded tracking information.
What to check before you leave the boat: The GPS Tracking page shows the most recently uploaded information. A valid value on the local DC page confirms that DataHub Pro is receiving the value over NMEA 2000. Check the GPS Tracking page Updated date and time to confirm that DataHub Pro has an internet connection and is updating your GPS Tracking data.
What you can expect to see
On the local Services > NMEA > DC page:
Each detected battery or alternator appears separately.
Victron Cerbo GX sources can show the enhanced Victron field set.
Other compatible sources show the general voltage, current and temperature field set.
Unsupported or unavailable measurements show NA.
Example GPS Tracking Page > Side Arrow > Boat Data > More button (down arrow)
On DataHub GPS Tracking:
Supported battery values appear under Boat Data > More.
Different battery instances may display different fields.
Important limitations
The DataHub does not measure the electrical values itself.
The DataHub does not configure or control the battery monitor, BMS, Cerbo GX or alternator regulator.
The local page is read-only. You can label the batteries in the DataHub; however, this will not be reflected on your GPS Tracking page.
The feature does not provide configurable battery-protection alarms.
GPS Tracking depends on the DataHub, Tracking configuration, subscription status and a working upload path.
Battery information should not replace the source equipment’s own alarms or protection systems.
Why are some fields missing?
Different battery monitors, BMS devices and sensors provide different information.
For a Victron system, first check whether the value appears in the Cerbo GX interface. If it is unavailable there, the DataHub cannot display it.
For another NMEA 2000 source, the general DataHub DC status page will display and upload any data it can interpret.
For detailed troubleshooting, see DataHub Pro: NMEA DC Status Compatibility and Troubleshooting.