Sorry to hear about your battery, it is really annoying to wake up to a car that doesn’t want to start.
So it seems that the battery was drained from 14v to 5v in about 7 hours, I haven’t done the math if this is possible if the device was running the entire time, but given the missing events between the two voltage readings, it looks like the device has not been running.
That you have a reading of 4.67v does not indicate that the critical level is not working.
As you probably know, the device is by default configured to wake up from a voltage change of +0.2v within 2 seconds.
And we have seen where the battery voltage can change at random times, which is likely happening because the car will charge or run some maintenance on the auxiliary battery, which causes the device to wake up.
This trigger will also wake up the device in this situation, where the battery voltage is low, but the safety cut-out is still active, so it means that the device will only be up for 4 minutes, before it is shut down by the safety cut-out - and in this period the device will log data as usual, which is likely why you see the above voltage reading.
All the events logged on the device, should be sent to the cloud, and you can see those in the events page, but the log on the device could have more details that could indicate if the device was actually running between the last voltage reading, and the low value, or if something else has caused the issues.
So if possible, we’d really like to take a look at the log from the device, maybe both the syslog and the minion log.
Please send it to firstname.lastname@example.org - then we can investigate what has happened.