how are the 12 volt batteries charged

[llcsf]

curious how these batteries get charged…

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[Whale Blubber]

I'm told that under the 12V there's a DC to DC converter box that draws from the high voltage battery pack. But I have no personal knowledge of this.

 

[R1DEW/ME]

I am getting a battery replacement rn at the SC they are also installing a new dc converter. I don’t know the exact science but yes when the 12v gets low or when you are plugged into a charger at home it will top them off.

As far as if it’s every time car is started, plugged into a charger, or at a specific voltage before it starts the 12v charge I don’t know.

Just know that the car requires the 12v to start a lot of the cars functions then it switches to the battery pack. That is why I had a 84% soc but couldn’t turn on my car, or even unlock it for that matter without jumping from tow hitch area

 

[Electrified Outdoors]

Your correct. The HV system is 400v in the Rivian. There is a DC to DC converter that steps the voltage down to 12v. It's powers all the vehicle electronics that run on 12v power and it will also kick on to maintain the 12v battery when needed.

 

[ekirkpatrick]

So when you are in camp mode or stopped and not charging and are using 12v outlets - does the HV battery still keep the 12v batteries topped off?

 

[River Ghost]

From how the service technician described the system, when the 12 volt battery is drained to a certain level it triggers a relay to the HV battery so that it charges the 12 volt battery. So the only way for the 12 volt battery to fail is if the battery fails, the HV battery is at zero charge, or in my case, there is a break in the wire to the 12 volt battery.

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