Vebus: Add BMS Connection lost alarm

[vejpasop]

Add an on alarm on BOL frame timeouts and VE.Bus BMS frame timeouts. See https://www.victronenergy.com/live/mppt-error-codes#err_67_-_bms_connection_lost

Multi firmware >= 502 supports a BOL frames timed out status flag.

mk2-dbus:

D-Bus path/Alarms/BmsConnectionLost will be added to mk2-dbus

Todo:

• [x] Add to mk2-dbus
• [x] Add to GUI
• [x] Add to VRM

[vejpasop]

Implemented in mk2-dbus v3.50

[mpvader]

@vejpasop : when this happens, do you show both a low voltage alarm and a BMS comms lost on the dbus? In that case, isn't it better to supress the low voltage alarm?

cc @izak

[vejpasop]

Indeed the the low voltage battery will be shown along with the BMS comms lost. Suppressing this alarm in vebus-interface is not really favorable (in my opinion) . The low battery alarm will usually come up before the comms lost. And after the comms lost it takes a while (>20 seconds) to clear the low voltage alarm, afterwards it will go through a low battery warning. This has to do with the charge engine state in the Multi.

[mpvader]

Hi @vejpasop you wrote:

Indeed the the low voltage battery will be shown along with the BMS comms lost. Suppressing this alarm in vebus-interface is not really favorable (in my opinion) . The low battery alarm will usually come up before the comms lost. And after the comms lost it takes a while (>20 seconds) to clear the low voltage alarm, afterwards it will go through a low battery warning. This has to do with the charge engine state in the Multi.

So, if user sees low voltage and error 67 at the same time, what he/she needs to look at is a comms issue.

And not have to think about battery running flat.

right?

[vejpasop]

Correct,

Only it is note error 67 but a /Alarms/BmsConnectionLost

[mpvader]

Can you share me screenshot of how that looks in the gui?

[vejpasop]

[warwickchapman]

Have tested this with site 308284.

GX

Product | C014 Firmware version | v3.00~42

VE.Bus

Product | MultiPlus-II 48/5000/70-48 Firmware version | 502

I unplugged the the VE.Bus cable from the GX device to simulate GX failure and after 30 minutes, nothing happened in 30 minutes.

I unplugged the BMS CAN cable from the Cerbo for the BYD BMU and after about 4 mins 30 seconds the BYD BMU shut the batteries down. The Cerbo reported a low battery and then continued running for an hour with the DC bus energised by the AC Input. I reconnected the BMS CAN cable and fired the batteries up again:

I will try this on another system with Freedom Won and report.

[vejpasop]

Number 1 can be explained: The BMS connection lost alarm in case of a managed battery is triggered by the Multi. So the Multi tells the GX device that it did not receive battery management messages for at least 5 minutes, If you unplug the VE.Bus cable from the Multi the GX device can not read the status and will therefore not show the BMS connection lost.

Number 2 where you disconnect the CAN cable should have triggered a BMS connection lost. I will look into that.

[vejpasop]

It works on our BYD setup. Disconnected the CAN cable of the BYD only. (So GX device remains connected). After 5 minutes I get the alarm.

[vejpasop]

@warwickchapman Found it. I looked on your site. You need to update the MK3 in order for this to work.