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z-zk-z avatar image
z-zk-z asked

Is it safe to have two Battery Monitors, should I remove one?

Hello,

I am using a Victron Smart Shunt (aka Battery Monitor) feeding battery data to other components in my setup (e.g., MPPT charger). Please see my first two setup photos. I recently learned how to have my EG4-LL (version one) batteries to communicate with Cerbo GX (photos aren't showing the communication cables between batteries and Cerbo GX). As you can see from the other photos, I now have two Battery Monitors in my setup. Should I remove the Smart Shunt (it seems the battery communication has more data included, so I should keep that and remove the Smart Shunt)? I also like to know, if it is safe to have two Battery Monitors in my setup. It seems the Smart Shunt is reporting higher SOC value, however the reported charge current and voltage values are similar from both Battery Monitors (see photos, which are captured at different times). Thanks in advance for your reply...


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BMSSmartShuntbatteryVE.Canmonitoring
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2 Answers
JohnC avatar image
JohnC answered ·

Hi @z_zk_z

Victron don't recommend their installers provide more than one SOC reading source, as clients get confused with a second, resulting in complaints and uncertainty. There's likely no real issue with your system because you're aware of it.

That's of course providing your network data is using the correct source. If you're using DVCC (whether deliberately or Forced on by the battery connection), it would be prudent to check what's selected there to provide the master reference data (all types) for the whole system.

Having 2x could also foul your summaries, VRM, etc. If you're happy with how the batt link is working, maybe you could repurpose the shunt more usefully as a dc load monitor or something. They can be reallocated and set to other duties as you choose.


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z-zk-z avatar image
z-zk-z answered ·

Thanks for your reply. DVCC is disabled (I don't even know what that is), anyway I found out that Victron software allows a user to select specific Battery Monitor (see photo below). The menu is located under Settings, System Setup, Battery Monitor. I used to have the Automatic option and I then selected the EG4-LL on CAN bus option. I started getting tons of warnings when the batteries got to 100% SOC which were cleared after a few seconds, so I decided to go back and using the SmartShunt as my Battery Monitor, regardless of the face that everything seemed to work fine. I am still getting those warnings with SmartShunt as my Battery Monitor. I guess, I could disconnect the cable for the EG4-LL CAN BUS (batt link).



Device		 Triggered by Description Started at Cleared after

Battery Monitor [512]

Automatic monitoring

High voltage alarm: Warning

2023-02-20 15:22:21

 3s

Battery Monitor [512]

Automatic monitoring

High voltage alarm: Warning

2023-02-20 15:22:03

 3s

Battery Monitor [512]

Automatic monitoring

High voltage alarm: Warning

2023-02-20 15:21:48

 2s

Battery Monitor [512]

Automatic monitoring

High voltage alarm: Warning

2023-02-20 15:21:37

 3s

Battery Monitor [512]

Automatic monitoring

High voltage alarm: Warning

2023-02-20 15:21:24

 3s

Battery Monitor [512]

Automatic monitoring

High voltage alarm: Warning

2023-02-20 15:21:09

 2s

Battery Monitor [512]

Automatic monitoring

High voltage alarm: Warning

2023-02-20 15:20:56

 3s


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JohnC avatar image JohnC ♦ commented ·

@z_zk_z

Your system is complex in some ways, and you owe it to yourself to find out about DVCC. It's not rocket science, see the Cerbo manual. It just helps your system talk with the same measured values.

Keep your CAN link to the batteries. On the face of it, it seems to be working ok. Victron has called the BMS a 'Battery Monitor', and allocated it the 512 identifier.

Those error messages come from 512, but aren't messages directly related to SOC. They're overvoltage warnings from the BMS, and you should deal with them as such (like maybe you're overcharging them).

If you can't trust your BMS you have a problem. And I'd be inclined to return to it's SOC as your display, so that you can always see what the BMS sees, rather than an external (and possibly untuned) shunt.

Victron have documented a bunch of batteries they've tested. I suspect yours may be similar to Pylontechs (lots of clones about), so take a look there to get some clues about where to head with your optimizing steps. https://www.victronenergy.com/live/battery_compatibility:start


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