question

roger-gregory-allen avatar image
roger-gregory-allen asked

Connect BMV shunt Wirelessly to Cerbo GX?

I have an RV installation where my batteries are in one bay, and a Multiplus and Cerbo are in a separate bay. Due to how the batteries are wired, the only place I can install the shunt is in the battery bay, and there is no space to have the Muliplus in the battery bay.

The problem comes from my inability to run a cable between the two bays. A wireless bridge for the VE.Direct connection would solve my problem. I have not been able to find any solution for that. The closest I’ve come is using the VE.Direct LoRaWAN module and a gateway to connect to VRM, but that does not get my battery information available locally (via the Cerbo and a GX Touch 50).

Has anyone else faced this issue and found a solution?

Thanks,
Roger

cerbo gxVE.Directwiring
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neil-mclaughlin avatar image
neil-mclaughlin answered ·

Hi Roger,

Since I am watching this forum closely for an answer to my own question, I saw your question and I can inform you on what I just completed. My Victron shunt is located in the battery compartment. It is connected to the BMV-712 via ethernet cable. The BMV-712 is located in the accessory panel next to the main electric panel. Then, I ran a VE-Direct cable from the BMV-712 through to the Cerbo GX that is located in the aft cockpit locker on the inside of the hull next to the Multi-plus Compact Inverter / Charger. So, with the BMV-712, there was no need to run a cable from the battery compartment to the cockpit locker. All the BMV-712(or shunt) data is appearing perfectly on the Cerbo Remote Console and VRM Portal.

I hope that helps.

Neil

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roger-gregory-allen avatar image
roger-gregory-allen answered ·

Thanks, Neil. Your set up is similar to mine, just substituting "locker" for "bay" :). I also have a BMV 712 (should have bought the smart shunt, but in the early version of the project, I didn't realize that). It sounds like you are running a cable from the battery compartment to the 712 in a panel, and then from the 712 to the Cerbo near the Multi - that is, running cables from the Cerbo and the shunt to a common, third location. BTW, that is not ethernet between the shunt and the 712 - it's RJ12 (6 connectors) whereas ethernet is RJ45 (8 connectors). Incidentally, VE.Bus connections are also RJ45, but not the same protocol as Ethernet (I learned the hard way).

I don't really have such a third location. I would happily leave the 712 in the battery compartment and only connect by VE.Direct to the Cerbo, but that leaves me with the same problem - getting from the battery compartment to the Cerbo (which cannot be in the battery compartment).

One wild idea I'm considering is using two Raspberry Pi's, each with WiFi, the Venus OS and the VE.Direct to USB connector. There should be some way to periodically read the BMV with the first RPi, transmit that to the second RPi over WiFi and have the second Rpi write the data to the Cerbo.

I think something like that could work, but it seems like an awful lot of effort and expense.

So, still looking for some clever wireless bridge for VE.Direct.

Thanks,
Roger

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neil-mclaughlin avatar image neil-mclaughlin commented ·

Yes, Roger, I never even looked at the cable to see if it was RJ12 or RJ45 as it was shipped with the unit and I just plugged it in. You are definitely right. Good luck with your hunt for answers!

Neil

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Peter Buijs - NL avatar image
Peter Buijs - NL answered ·

I think VeDirect is a 19200 baud serial connection. Maybe a 2x serial to WiFi converter can help...

usr-w600-low-cost-industrial-serial-rs232-rs485-to-wifi-converter

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roger-gregory-allen avatar image roger-gregory-allen commented ·

Thanks for the suggestion. That lead me down a path that I think may be fruitful. The work done by @Vickey in this post may lead to a solution. In that case, the source device was an energy meter, plus there was an additional need to use Ethernet over powerline step, but the principle is the same.

For my case, I could use two of the USR600 converters with two VE.Drect/RS323 interface cables to create my wireless bridge.

Still a fair amount of work, but not nearly so much as essentially recreating the USR600 with a Raspberry Pi.

Thanks for the suggestion!
--Roger

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Peter Buijs - NL avatar image Peter Buijs - NL roger-gregory-allen commented ·

https://beta.ivc.no/wiki/index.php/Victron_VE_Direct_DIY_Cable

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