My 12V battery & high voltage battery pack died on the same day at the same damn time?

[billyho613]

Bad luck or has Tesla misdiagnosed this?
I booster the 12V yesterday and the range is still showing as 150+ Miles....ust as it did when I parked it last week my buddy swears I just need a new 12V, but Tesla SC is saying no way, you need your third battery pack installed!

Original battery pack lasted 60K miles died in 2019

Now 35K miles later--- DEAD AGAIN?


Gas is cheaper than these kinda shenanigans

 

[NV Ray]

Yes, unfortunately there have been several cases where initial 12v recommended solution actually was faulty HV pack from the start.

 

[EVRider-FL]

Is the HV battery out of warranty now? I assume the first replacement was covered under warranty.

 

[shahryaran]

You should always check alerts in service mode. Sometimes some alerts won't show up on the consumer side

 

[EVRider-FL]

You should always check alerts in service mode. Sometimes some alerts won't show up on the consumer side

Yes, but on the other hand, a lot of the alerts in service mode are benign and nothing to worry about.

 

[peakay]

Having just been through this, something fails and then the car burns out the 12v battery as a result. In my case it was a rear drive unit, but my understanding is it could have been the HV or the DCDC converter

 

[vindroid]

Having just been through this, something fails and then the car burns out the 12v battery as a result. In my case it was a rear drive unit, but my understanding is it could have been the HV or the DCDC converter

is yours a model S too? which year?

 

[IronCoffee_Max]

This happened to my mom as well a few months ago. Model S Raven. Thankfully under warranty.

 

[Hank42]

It sounds like bad luck right?

The 12V needs a constant supply from the DCDC converter driven off the main pack to survive. If there is a HV isolation fault - from the drivetrain, or main battery, or coolant heater, the power to the 12V is cut off and the MCU and other 12V systems draws thier power JUST from the 12V battery. When that supply gets too low, the battery "dies". The knee-jerk reaction is to replace it, only to find a bunch of more sinister failure codes.
Some people suggest checking alerts, but I don't think the "12v low" alert works anymore - I have not seen it in multiple tests with "bad" 12V batteries.

"Why did the pack fail?" is probably what you should be more concerned about - sure it's the pack? Might be your drive unit - have them check for coolant there - that often gives similar symptoms of a pack failure. Also, just read this is your 3rd? Have them check that battery connection interlock - moisture there will cause the next pack to "fail".