Random cell voltage drops

I’m using [GitHub - Batrium/WatchMonUdpListener: WatchMon UDP Binary Listener translates to JSON and stores to influxdb] to push the udp messages to an mqtt broker.
In NodeRed I just subscribe to 3e33 topic of the mqtt-broker. That broadcast multiple times per second a json like this:

	"first": ":",
	"MessageId": "3e33",
	"nd": ",",
	"SystemId": 5307,
	"hubId": 30553,
	"MinCellVolt": 3.325,
	"MaxCellVolt": 3.34,
	"MinCellVoltId": 2,
	"MaxCellVoltId": 1,
	"MinCellTemp": 22,
	"MaxCellTemp": 24,
	"MinCellTempId": 1,
	"MaxCellTempId": 33,
	"MinBypassAmp": 0,
	"MaxBypassAmp": 0,
	"MinBypassAmpId": 0,
	"MaxBypassAmpId": 0,
	"MinBypassTemp": 22,
	"MaxBypassTemp": 24,
	"MinBypassTempId": -39,
	"MaxBypassTempId": -7,
	"AvgCellVolt": 3.332,
	"AvgCellTemp": 23,
	"NumOfCellsAboveInitialBypass": 0,
	"NumOfCellsAboveFinalBypass": 0,
	"NumOfCellsInBypass": 0,
	"NumOfCellsOverdue": 0,
	"NumOfCellsActive": 48,
	"NumOfCellsInSystem": 48,
	"MinBypassSession": 0,
	"MaxBypassSession": 0,
	"MinBypassSessionID": 0,
	"MaxBypassSessionID": 0

then I’m just waiting for every event which is in the range I’m interested in and get the faulty ones.

There are many more topics in the UDPListener where you can subscribe on.
Saving that data to influxdb and creating some nice Graphana Dashboards is worth it :slight_smile:

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thank you for sharing, but wow, that is too much effort for me. I’m trying a simpler solution to figure out, if it’s always the same cell or not:

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Tonight 2 “events” , this time cell 33.
It looks like if it’s always the first cell of each K9

		"1.89": {
			"33": [
		"1.425": {
			"33": [
		"2.36": {
			"33": [
		"1.885": {
			"33": [
		"1.415": {
			"33": [
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yes, for me it was always No. 17 (1st cell of 2nd pack). I’ll wait for one more event, then I’ll swap the packs…

Swap the packs?
You mean swap the cells in one pack, or swap the K9 between the packs?

I have the K9s tied to the packs and meant swapping the order the K9s (including the cells) are daisy chained to the WatchMon.
But that doesn’t make sense anymore, I just had a drop on cell no. 1.

I have the same problem for a few days. It has happened 3 times so far. But it happened to different cells.

Hardware Ver. 14.5
Firmware 14.3.46
Software 2.17.39

Hello, it just happened again.

Any ideas what the problem is or what I can do about it?
Thank you.

Batrium is working on it, we have to be patient.


Just a question, I first configured my ShuntTrip on the Relay, by:
That is triggering all the time, when a cell reports this kind of low voltage out of nothing.

But I monitored now the
which is not changing during the low voltage episodes…

So I like to change my ShuntTrip to that Relay-State, but will the Critical BattOk State change. if there is a real low voltage on a cell?
Is in that case if the critical Voltage is breached, this time relevant?


So if I change that to 3sec, the CriticalBatOK will also be false for this false positiv VoltageDrops?

Unfortunately, I always (app. once a week) have short cell volt drops, too.

Since a BMS is a safety component, I would ask you to react accordingly.
Hopefully Batrium will find a SW solution…

HW Version 14.5
Firmware 14.3.46
SW 2.17.39

Hi everyone!

To work around the current issue, we will be pushing a PREVIEW release to restore the original Victron method. We are currently testing it internally and we’ll publish it in the coming days once we see favourable results.

We are pushing this preview release to ensure that 2.17.40 addresses the immediate issue.

We thank you for your patience on this matter.

Full update here: ATTENTION: Update for Victron Users [Upcoming Preview Release]

ATTENTION: Victron Users

For Victron users, we advise staying at the most recent stable release, Build 2.17.27 for now as we did not anticipate any issues when we created the new build.

Updating to preview release 2.17.40 is optional as Build 40 restores the Victron logic, however, the issue with the reported voltage spiking is something we are still currently investigating and working on.

FULL UPDATE HERE: ATTENTION: Victron Users [Preview Release 2.17.40]

was someone in the community able to find out a cause or achieve an improvement through an action?
I would be happy if the community or the readers of this message could give direct feedback on their experiences and the level of knowledge. thank you very much

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Please be advised that we now have a new preview release (Build 42) that aims to resolve the random cell voltage drops that have been reported on most Victron equipment.

Before we release it to the public, we would like to test and work with a couple of Victron systems to make sure it is working as intended. If you are interested in testing this build, please contact us via email: info@batrium.com

Hello Renzee,

what a pity. I will leave tomorrow for vacation and am a bit scared to make changes to my system right before I leave not being able to revert in case of issues.
Sorry for not being able to support here. I will test it once I’m back, after 23rd of July.

Cheers, luphi

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I run it now for 2 days.
Up to now no celldrop.
Looks good.

I have requested this new version to test here - I see spikes and drops via VRM

Can you please send us a copy of your Manual Extract Report so we can verify? You can also provision your device for remote access so we can look at your system remotely. Please direct the necessary information to info@batrium.com.

Unfortunately the old CellDrops comes back again every day.
Report was sent.