Communication between Cellmon and Victron Cerbo Gx drops in and out

The Comms between the Cellmon and the Cerbo Gx ,as well as to the software via WiFi drops in and out continuously . It will disappear for 20-30 seconds sometimes longer then reappear. Athough this is a little annoying it is fine as long as it is not having any effect on the system. Has anyone else experienced this. I have re-terminated the connections many times.
Now when I run my Generator the bulk charge will kick in via Victron Quattro 24/5000 but it will only stay charging for a minute then drop to nothing it will also stop the two Mppts from charging. A minute later it will kick in full charge again until it stops a minute later. Would the BMS be controlling this? It was working fine previously. I have been looking at the victron configurations to see if they are correct but now I’m starting to think its the BMS that’s the problem. When I put load on the Inverter it stays powering no problem which suggests the Generator is fine and the Quattro is fine , I feel its just the control of the charger that’s the problem. Any advice would be most welcome.

Hello Aiden,

I had the same issue and reported to Battrium Support. It seems that this has troubled others similar as you and me.
My Batrium SOC droped out quite precisely every three minutes, and this started in the morning almost every day at the same time when MPPT 150/35 coinstantly started to work.
I found out that when SOC request via Can-bus is send from Cerbo GX it seems that WatchMonCORE does not send reply, looking at the Tx and Rx packets at Cerbos GX’s Remote Console on LAN: Settings - Services - BMS-Can port - Network status.
My components are mounted very close to each other on a wooden board and my w-lan is quite weak at the location.
So I was assuming wl-an interferences with MPPT’s step-down current PWM switching.
When CellMon Core is without w-lan connection the issue was gone.
That was fine for me in general but the cool supervising and testing configurations of the Batrium via w-lan then of course is not possible.

Yesterday I received Batrium Support e-mail recommending new beta firmware for stability testing. That made me very happy, Update was successful and CAN drop outs are gone so far ;-))

I’m looking foreward to your upcoming experiences.
Stay charged, Ralf form Germany

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I have the exact same problem here.
Victron dropping periodically out due to CAN issues. I figured they were somehow related to WiFi but there was no good way to read anything from a logfile.
I will contact Batrium so I can get my hands on the 2.17.42 and give it a try.
Some hope at last!
thanks, teemischer

Update: I am running 2.17.42 for about a month now with success:

  • no voltage spikes/drops
  • no more CAN disconnects between Watchmon and CerboGX
  • stable wifi (not sure what caused this change)

Very happy so far, thanks @batrium !


Thanks for this feedback, @teemischer.

We’re currently in the process of working n the DVCC integration in the Victron inverter. We’re optimistic that this feature will be included in an upcoming release in the near future.

Thanks for your patience.

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Please be aware that Victron sells several devices that support its distributed voltage and current control (DVCC) system. This community seems to call them all inverters. Some inverters have chargers built in. Some don’t. There are devices that are only inverters or only chargers. There are solar max power point controllers that act kid of like DC chargers without an inverter. This is quite different from an inverter used for a rooftop solar install. The BMS doesn’t communicate with any of them as you suggest. It only sends status messages over the CANbus to a Victron GX device. The GX device controls the chargers and inverters, etc. I hope you don’t focus only on inverters. It’s the chargers that are the most concerning - whether they include an inverter or not.

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Hello Teemischer,
are you still using version 2.17.42 or have you already updated to x.43?
If so, does it run as well as the x.42 version?
If no, could you share the x.42 version?

Thanks and greetings

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I have the issue also.

every 180 seconds - as precise as a swiss train - the WMCore reboots. During startup, the battery is charging from the grid, after it’s hard discharged.

CR1220 is taken out of the WMCore.

Anyone any idea? I get really frustrated with this “top notch” product.

running x.27, x39 and x.43 is the same.

sorry, can’t say yet. I am still running .42 and I am on holiday till September. Will install newest version then and of course report here.

update: I updated to .43 this morning. no issues so far.
Will keep you posted.

Hello everyone!

We have a new preview build, Build 46, that we have been testing for a week that aims to address the voltage dropout issues reported on K9 systems. So far, we have not seen any voltage anomalies.

If you have a WMC-K9 system and would like to test this preview build with us, please send an email request to and the download link will be sent to you.

I have a similar issue, currently on 46, with SMA SI’s … has been an issue for a couple years where the SI believes the signal from the batrium drops and at best it simply trips the relay connection, at worse it restarts the whole inverter and and very worst it turns the inverter off completely.

I have monitored CAN traffic while it was happening a couple times and it appears the batrium is sending signals when the SI believes it is not. The logs clearly show the SI stating the SOC is out of range or it has lost the BMS signal while the batrium is sending the right SOC or a signal in general.

I have sought out help from other DIYer’s and documented some of the information on other forums but haven’t reached out here yet. Batrium SMA Sunny Island Integration issue? | Page 2 | DIY Solar Power Forum