I recently suffered 12v battery failure in my 451 ED3. I think that battery had been in there a long time (from new?) but the car was in use only a couple of days before and had fully charged so no chance for the HV battery to get depleted.
I have now replaced the 12v battery (nightmare job on a RHD car) but although the car runs ok, there's an error on the dash:-
HV System -> Workshop
Can OVMS read and/or clear such error codes from the car?