Aux Batt Reference Voltage Issue

[RowdyDoc]

Seeing an issue with the detection logic for the voltage reference.
Basically the logic grabs the voltage while the aux battery is charging sometimes.
May be a race condition whereby the voltage is updated prior to the charging status being detected.

Attached a battery monitor trace that shows the issue.

This is causing a problem with the aux battery protection shutdown logic.
I am trying to ensure that the OVMS goes into sleep mode if it drops the battery SoC by a significant amount (which is maybe 100->75% which I am calling 12.4V)
Tried to overcome this with a manually entered reference voltage of 14.8V and an alert threshold of 2.4V -> this effectively ignores any detected reference voltage, but because the alert is only cleared at 14.8-0.6*2.4=13.4V, it effectively doesn't clear unless charging kicks back in again (even if the voltage "dip" was quite short - which it is in many cases).

Possible solutions here:

1. Require that the voltage drops below the alert threshold for a number of consecutive periods prior to setting the alert (ideally a parameter, but at least 5 minutes based on the occasional dips I am seeing).
2. Allow ignoring of the detected reference voltage (and just use the manually entered parameter) - this would allow me to put in 12.6V and a alert threshold of 0.2V ie alert cancelled if the voltage dips to 12.3V then restores to say 12.5V. This is probably the most solid solution from my pov.
3. Fix the reference voltage detection logic to require that the aux charging status is still off for the next period before locking in the new value (however, I think the reference voltage detection is never going to be very solid - so prefer to just be able to disable it).

[dexterbg]

I think this is most probably a vehicle specific issue of not setting the 12V charging state in time.

The 12V reference logic takes a calmdown period of max 15 minutes into account, but only does the countdown when the vehicle isn't charging the 12V battery. With a correct implementation of the 12V charging state, the system won't take a wrong reference voltage level.

If your vehicle adaptor cannot read the 12V charging state from the vehicle bus, it should not try to derive it from the voltage level. Or if it does, it should maybe adjust the m_12v_ticker state variable to accomodate the delay.

Regarding your actual use case, maybe you can now better use the new 12V shutdown feature for this?

Regards,
Michael