question

Derek Gaeth avatar image

Ramarine Axiom not displaying Aux Battery Voltage Correctly over NMEA2000

I have just installed a new Axiom MFD on my boat and connected the Cerbo GX via NMEA2000. I am able to see the house battery voltages correctly, but. I cannot see the Aux battery voltage. It is displaying 39-40v and it should be ~13v. Do I need to change the PGNs on the Cerbo to make this work on the Axiom?


BMV Battery Monitorraymarine
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4 Answers
Derek Gaeth avatar image
Derek Gaeth answered ·

Problem solved. The issue was the solar MPPT controller and Raymarine's implementation of NMEA2000. I logged into the command line on the Cerbo and used dbus-spy to change the Settings/Vecan/can0/Forward/solarcharger/278/DCDataInstance0,1 to 3,4. This resolved the conflict and now my Aux battery shows correct. DCDataInstance 1 was the solar array voltage. Instance 0 was the house battery and was the same as BatteryInstance0, which is why it always displayed the correct voltage.

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Paul B avatar image
Paul B answered ·

You should also be seeing the below screen on the axiom without using any PGNs - its selected under apps - then you can see all the BMV info under settings - plus you also have full control over the Cerbo as well - I know this is not a direct answer to your question - as I presum you are adding extra data info selections - I dont know what the Aux bat PGN is that would be coming out of the cerbo - the but it maybe coming out as bat 2 or instance 2 battery value so presume you have tried all those ???


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Hi Paul, I don't have the Cerbo connected via Raynet, only NMEA200 so the HTML5 app does not work. Or should I be looking somewhere else?
kevgermany avatar image
kevgermany answered ·

Do you have a common earth between the batteries and Cerbo?

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Hi, yes. The Cerbo is not doing the voltage measurement the BMV is and that displays the correct voltage. So it is an issue with how the data is being presented or what value the Raymarine Axiom is reading.
Derek Gaeth avatar image
Derek Gaeth answered ·

I used my Veratron App to look at the NMEA2000 data yesterday. It appears that the correct voltage is being sent, but the value is changing very quickly every second to some other value. I believe this is causing the Axiom not to pickup the correct value. I have confirmed the broadcast is coming from the Cerbo as it stops when I disable to Can-out function. Any help would be appreciated.

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