@NY_Rob - I know you sold your first Rivian (I believe you'll be back someday), but I, for one, really appreciate your Rivian knowledge and continued active participation in the forum. Thanks!
Thank you, I appreciate that!
For me, because I have a current 12v battery warning and don't want the 12v to die and leave me stranded until it can get replaced by service. I agree, the HV should act as an alternator but something is clearly amiss on a 1 year old car. "Restoring" the battery as much as possible with a battery conditioner/optima charger was just a test. I also wanted to see what the charger determined as the current percentage and whether it was able to improve state of charge - it did not seem to do much though. When I connected it was showing 75% charge and remained that way after 14-16 hours I would estimate.
The hypothesis is that waking up the HV battery to trickle charge the 12V has A LOT of electrical overhead (running computers, etc) and that leads in some cases to the very significant vampire drain many are seeing. So the battery maintainer in theory should require the vehicle to wake up far less and minimize vampire drain. The reader can calculate the monetary and environmental cost of 1-2% vampire loss per day over time, assuming the battery maintainer minimized vampire drain.
The theory here is that the DC-to-DC charger from the HV to the 12V battery, would STOP charging when drawing too much current for too long in order to protect the HV battery and it's charging circuitry.
In the instances you're referring to, those are problems with the battery themselves and not the HV etc. So even if the battery was still on a trickle charge, the same problem would occur because the 12v battery fell below voltage window due to either lifespan or in many of Rivians cases, bad batching.The theory here is that the DC-to-DC charger from the HV to the 12V battery, would STOP charging when drawing too much current for too long in order to protect the HV battery and it's charging circuitry.
When that happens, then your 12V will be drained and your car will shutoff. That's how and why many of us found our R1T 'dead/bricked' one day
My HV battery state of charge was 69% when it died, so plenty of juice to still keep the 12V charged but a failsafe device kicked to avoid further discharge and voilá!
