One of my clients has eight US2000B batteries (the older version). They’re all running the latest Pylontech firmware, yet they still trigger an over-voltage alarm.
I’ve lowered the voltage in DVCC slightly, which has reduced how often the alarms appear, but I suspect that one of the batteries contains a faulty cell.
Is there anything in the Cerbo GX debug data that would reveal which module might have the bad cell? If not, how can I use BatteryView to pinpoint the problem?
I’d prefer to work through Cerbo GX because the installation is very remote; diagnosing the issue from a distance would let me make a single trip only to replace the bad battery once it’s confirmed.
Use vrm, load the bms min and max the battery and cell address is there. It is fairly easy to note a repeat offender using that.
As in you may find there will be cascade fail on the stack meaning now it has begun, there will be one following on shortly.
Which module (and by module I mean battery) has the min or max voltage is shown in Cerbo/VRM.
Which cell is the min or max, on that module/battery, you can’t know with Cerbo/VRM.
Therefore you use BatteryView.
The idea with Pylon is that you must allow them enough time to balance, as the balance is passive with max 70mA.
It could take up to 12 hours to fully balance a battery and with day/night cycling, this could be a problem.
I have in several banks now, noted a certain battery, gone to site and it is ‘the one’…
But usually after the one, several other follow in the next few months.
It does depend on the firmware older firmware doesn’t share addresses. And yes battery view is more in depth, not arguing it is a good tool.
But @peter wanted a way to see before he goes there.
The first two digits (01 - in picture) is the group number.
A group could have up to 16 batteries.
For example, I have only one group with 8 batteries connected in parallel.
The following two digits (06 - in picture) is the battery number in that group.
But which cell from the battery 06 is that max, I can’t say, you need BatteryView.
Otherwise no.
Well… kinda…
From Cerbo’s perspective, in this moment, you have there the “global” min and max voltage cell.
Meaning the minimum and maximum among ALL batteries in that group.
But you can find out, without additional software, the individual min and max voltage cell for EACH battery, individually.
But still, not which cell is the min and which cell is the max.
For this you need to SSH on Cerbo and send a request details command to the battery master and the master will respond with details.
I think which cell is less important as the whole battery where it resides would be replaced?
If the high cell and low cell are in the same battery repeatedly it is probably a problem battery.
Almost guaranteed that they have blown up like balloons and possibly even visible looking at the case bulging.
Nice screenshot saved me getting one. It is also good to see if anybare blocking charge as well.
No worries… they did not report that with the original FW. And as discussed elsewhere, there is better charging algorithm for the 48V Pylontech batteries when this info is sent to Venus, so my first attempt was to get them up to date and maybe they will balance themselves better. Before the FW update, they were also reporting Internal Failure at low SoC. This completely disappeared with the FW update… however the high-voltage did not.
