Vers 2.0 - Multiple Daly RS485 - BMS cable fault

[CaptKrisp]

Today I updated to version 2.0.20250729 from 1.3.20240705 and now constantly see BMS cable fault alarms.

System consist of:
3 - Daly BMS on single RS485 bus
1 - rPi 3
2 - Multiplus II, split-phase

I don't recall the previous driver version giving the "BMS cable fault" alarm.
The upgrade failed using "install.sh" from the then installed v1.3 and required manual install by pulling new install script, which succeeded
After the upgrade the driver logs showed many "invalid config" messages, which made little sense due to most of those configs were defaults of the previous "config.default.ini" file as well. At any rate, renamed the existing config.ini (which was the previous config file that appeared to have some new config options added by the install script) and started with copy of config.default.ini.
Modified the new config.ini to reflect only key parameters. Specifically:
MAX_BATTERY_CHARGE_CURRENT = 120
MAX_BATTERY_DISCHARGE_CURRENT = 150
MAX_CELL_VOLTAGE = 3.64
BATTERY_ADDRESSES = 0x40, 0x41, 0x42, 0x43 (4th battery, 0x43, expected to be added soon)
BLOCK_ON_DISCONNECT_VOLTAGE_MAX = 3.62
CVL_CONTROLLER_MODE = 2
CELL_VOLTAGES_WHILE_CHARGING = 3.650, 3.645, 3.625, 3.600, 3.375
BMS_TYPE = Daly
POLL_INTERVAL = 5

All other configs remain at default.

I hope this all makes sense as I described it.

Any idea the cause of this alarm?

BTW, I have another system still running an older version (maybe 1.2) with identical cofigs, except only 2 batteries on the 485 bus, and never receive any such alarm... if that's helpful.

Thanks for any guidance/feedback,
Cap

[CaptKrisp]

For those who are interested, I reverted to v1.6.20250131. This doesn't completely eliminate the occassional "battery cable disconnect" issue but it does greatly reduce the occurrances as seen by the driver and removes the annoying barrage of alarm messages.

[mr-manuel]

Did you try the latest nightly and this setting?

venus-os_dbus-serialbattery/dbus-serialbattery/config.default.ini

Lines 212 to 216 in 7c161b7

	; --------- BMS Cable Alarm ---------
	; Description:
	; Enable or disable the BMS cable alarm on the Victron system.
	; When enabled the alarm will be triggered if the driver detects a lost connection to the BMS for more than 60 seconds.
	BMS_CABLE_ALARM = True

[CaptKrisp]

Thanks for reply @mr-manuel
I did install the nightly version 3 days ago. The new BMS_CABLE_ALARM parameter does prevent the alarm when set to False.
There has not been an alarm notice since that time but there is still the log entries of communication problems and includes driver restarts.
Thanks for this addition.

It should be noted that since the original post a 4th battery pack has been installed on the RS485 bus. This occurred before the nightly version was installed.
The addition of the 4th battery pack does cause occassional "BMS cable fault" alarms for random packs but mostly for pack 4. This has occured 2-3 times since the nightly version was installed.
The total bus length is ~5m and the terminating resistor in BMS for pack 4 has been enabled.

I suspect the primary cause of these alarms is a combination of 1) the 9600bd comms in the Daly, 2) the serial driver process of open/close serial port for each BMS on the 485 bus.
If my suspicion is correct one way that can greatly reduce or eliminate such alarms is to institute a process flow of; 1) open the port, 2) read data from each BMS, 3) close the port.
Given the structure of the driver this might be difficult to implement. Althought, if I remember correctly, the Daren485 code seems to do exactly this so it might be used as a template.

Anyway, thanks for your efforts.

[mr-manuel]

Feel free to open a PR for it.