question

Hi have you read the victron pylontech setup manual? Take a look at troubleshooting section, there is a section about this

See: https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom

Hi @duivert,

I've read this about a 100 times (at least it feels so) ...
Do you refer to:
"Note: The “Limit managed battery charge voltage” feature should be left OFF, unless you are experiencing “High Voltage” or “Internal Error” alarms. These alarms can indicate that there is an internal cell imbalance in the battery. It may be useful in this situation to enable this feature, and then adjust the voltage limit down so that the batteries are able to balance charge without reaching over voltage internally. This imbalance is at a cell level, so might not be reflected as a high overall battery voltage if measured with a Multimeter. This can then be turned off once the battery has balanced itself properly." ?

At first I left this feature off as described there, then - after getting some alarms I set it to 52.5 and then to 52.0 Volts. Didn't help.

I *could* set it even lower, however, this morning - for example - the battery was down to 15% @ 48.80 V, so setting the limit to anything lower than 52.0 (but above 48.8) wouldn't have made any change, would it?

Also the Minimum/Maximum Cell Voltage (which I *assume* is reported across all 6 Pylontech modules) shows minimum delta of a few mV. No high voltage visible.

This system is setup up step-by-step, so first I only had one, then the two SmartSolar-Chargers (Bluetooth Network) in combination. Venus OS came about 2 weeks ago and the Pylontech connection was added just a few days ago.

So in case you're referring to:

'High voltage' warning or alarm shown on battery status

The 'high voltage' warning or alarm is not unusual on new batteries that are not yet balanced. To help the batteries balance quickly, keep the batteries fully charged until the errors go away.In an ESS system, set it to 'keep batteries charged', in an off-grid system the fastest way is to either charge / balance the battery before installation, or to fully charge with a generator if not enough solar is available to keep the batteries fully charged.
As you can see in the screenshot above, the battery was in float/absorption a couple of times. Originally (25 days ago) I've played with the Pylontech limit of 53.5 V, then I reduced to 52, 52.5 and 52 again - that was before the battery was connected to the Venus OS just 4 days ago.
The batteries were fully charged a couple of times as well as I had fully charged them one-by-one before connecting them to each other ...

What puzzles me is the fact, that min/max cell voltage is reported to the Venus OS (and VRM) and both Values are always pretty close (3-5 mV) to each other.
If there is/was any overvoltage internally, shouldn't that be reported as "Max Cell Voltage"?

More ideas welcome.

Have you manually set the config on the chargers?

I would suggest you wait until your whole system is ready and configured.

For what you spent I would have rather bought a cerbo, it eliminates issues with a Pi that ultimately makes support interesting.

Duivert is correct, I had exactly the same issue with my Pylontech setup (4x US5000) I initially set my max. voltage to something like 51.4V having a Cerbo is neither here nor there. The only real advantage is it has lots of inputs. After a couple of weeks it settled down and now Limit managed battery charged voltage is disabled.

hmm ... I will try ...

However, I still would like to understand where that "high voltage alarm" comes from and why it is not shown in the min/max cell voltages?
Either there is high voltage - then I would expect the "max cell voltage" value to reflect that, or there isn't any high voltage (as reflected in the min/max cell voltages), then I would expect no alarm.

Someone from Victron (SW engineering) should be able to explain where that message comes from. Since it does not show up in Venus OS I don't expect it to come from Pylontech but rather in the communication between Venus & VRM.
BTW: I did have a dbus-monitor running (on the Raspi) for a while - writing all the values to a log file - and couldn't find any traces of those alarms ... strange.

In the end, that doesn't leave a good feeling.

hmmm ...
"Plenty of reports here saying that Pylontechs can take a few weeks to settle down."
Okay, I can accept that. But WHY don't they show up in "Max Cell Voltage"?

Basically you're saying, the Pylontech BMS sends out the high voltage alarm (which the Venus/Cerbo does NOT show, but it does forward it to the VRM Portal). In parallel the BMS sends out Min/Max Cell Voltages (which the Venus/Cerbo does show and forward) and they all look fine.

This is like saying:
"My truck doesn't fit under that 14ft bridge. And, by the way, my truck is 10ft tall"

So there's two distinct points here:

1. The Pylontech BMS sends out high voltage alarms while Min/Max Cell Voltages shown are well within range - WHY?
2. The Cerbo seems to forward all the information it gets, but it does NOT show all of it.

Thanks for your support.