I've read a few of these posts but likely missed someone's explanation for why a 12v battery would ever die on a new truck? Presumably it was a new batter. Driving it presumably charges it. Vampire drain from what I understand drains the main batteries. So what is pulling all the juice out of a 12v battery so quickly, any ideas?
Not the R1T, but this has happened on the F-150 Lightnings as well. The general rationale there may..or may not apply.
Truck is manufactured and built, it then sits in a lot pending shipment, then shipped and can sometimes up to two months. During that time, it is rarely driven and not placed on a charger which leads the 12vDC battery to draw down.
The truck
should be recharging the 12vDC battery via a DC to DC converter from the main 400V pack during this time. However, Ford's service manuals reveal there are conditions in which the 12vDC battery will not recharge.
I don't have access to Rivian's service manuals, and the car doesn't even have some of these parts; but this may give a general idea that there may be conditions or situations where the vehicle is programmed purposefully to not charge the 12vDC battery.
Conditions where High Voltage (HV) to Low Voltage (LV) Energy Transfer is not supported
1) When the gear selection is not park (e.g. reverse, neutral, drive, sport etc.) the HV to LV Energy Transfer Feature shall deactivate and/or stop the energy transfer process
2) When the ignition status is not key-off (e.g. key-on, remote on etc.) the HV to LV Energy Transfer Feature shall deactivate and/or stop the energy transfer process and reset lock out period.
3) When OTA update is in the process with a software update (non-interruptible state), the HV to LV Energy Transfer Feature shall proceed after the Over the Air (OTA) software update is complete.
4) When HV to LV Energy Transfer Feature is in the process of an energy transfer, the OTA update shall stop the energy transfer and proceed with the OlA software update
5) When an internal error and/or fault is detected (e.g. HV to LV DTC etc.) the HV to LV Energy Transfer Feature shall immediately deactivate and/or stop the energy transfer process.
6) The HV to LV Energy Transfer Feature shall be enabled to provide energy transfer when vehicle is in "customer mode" or "transport mode". The feature shall be disabled in all other lifecycle modes.