I have the same issue, and I can see that other installation companies are experiencing it as well, at least here in the Czech Republic. The people I’ve spoken to have dozens of installations and are seeing the same problem, even on older systems. In our case, the batteries have been installed for almost six months, and I’m still getting High Cell Voltage alarms. The recommended temporary solution — limiting the maximum voltage via DVCC — has not resolved the problem so far.
In my opinion, this is a systemic issue. However, after one out of eight modules was replaced under warranty, BYD is now claiming that everything is fine and that this behavior is a feature, not a fault. I strongly disagree with that. The evaluation of the state of charge is performed by the battery’s BMS, not Victron. Furthermore, advanced diagnostics show that it’s always a different cell in the system that has the lowest voltage. It’s as if the balance is thrown off after each cycle, and the integrated BMS is unable to fix it. And if I leave the voltage limit in place permanently — which BYD recommends if I want to get rid of the alarms — then the system will never reach 100% charge. That’s just stupid.
