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edvanz avatar image
edvanz asked

NMEA network down when connecting NMEA2000 out from Cerbo GX

I have an NMEA2000 network with a lot of Maretron items, Cerbo GX with NMEA out, and a REC BMS master-slave setup. The REC Bms is connected to the BMS Can on the Cerbo GX with 500kbps, Ve-can has 2x MPPT smart solar, and Skylla running on 250 kbps. Ve-bus has 2x Quattro in paralell. As soon as I connect the Ve-Can to NMEA cable every device after the Cerbo GX on the NMEA network disappears from the n2kanalyser software( greys out). I have used the original Ve-Can to NMEA cable and have made 2 new ones myself with all the same results. The Victron network on its own works great and the "maretron" network including all the navigation items runs great too. The NMEA network is rather big and consists of 2 networks bridged by an NBE100 from Maretron. Has anybody seen this before?

NMEA 2000 - N2K
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4 Answers
Patrick avatar image
Patrick answered ·

I have the exact same issue. Patiently waiting for some wisdom.

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urbansk answered ·

I have the same behavior too!

https://community.victronenergy.com/questions/133949/connecting-smartsolar-15070-vecan-to-nmea-200-neto.html

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jwfrary avatar image
jwfrary answered ·

Hi all,

I expect your issues are to do with how you have connected the ve.can network to the nmea network.

There are two ways to achieve this.

1. Use a spur (the ve.can to N2k cable) to connect each ve.can device to the network backbone. Place a terminator at each end of the backbone.

2. Daisy chain the Ve.Can network, have a terminator at the far end. Connect the ve. Can cable as a continuation of the backbone cable removing the terminator. The other end of the N2k network should have the other terminator.


You should only have 2 terminators in each network.

Be careful about voltages, some devices need power from the network others feed power in, though the N2k network can be 24v often they are 12v only in the case of raymarine and simrad so take care!

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urbansk avatar image urbansk commented ·

@Jwfrary I have a fully functional NMEA 2000 network. Connecting a Smartsolar 150/70 ve.can using a Victron ve.can to N2K cable with no fuse installed kills the network!

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fguiot answered ·

I have a similar problem. Actually I spent a fair amount of time trying to troubleshoot the issue and here is what I believe I found:

It seems that when there are too many N2K devices connected to the backbone, the Cerbo GX seems to send conflicting packets that creates issues with the GPS receiver or kill the communication between the MFD and the autopilot. Reducing the number of N2K devices seems to reduce the occurrences of the issue.

I don't have any tools for sniffing or troubleshooting the N2K protocol, but the wiring is correct with only 2x terminators (on the N2K backbone side), and only Cerbo GX attached to it.

Any hint?

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