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12v battery died while main battery was fully charged and car plugged in to charger

AaronD

Member
Feb 15, 2020
21
15
Salt Lake City
I don’t know if the car specifically avoids charging the 12V while plugged in, that would be weird. But it did turn out to simply be a dying 12V battery, complemented by the Tesla software doing a poor job of keeping track of the battery health, or rather not really tracking it whatsoever.
 
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ucmndd

Well-Known Member
Mar 10, 2016
6,670
12,532
California
Basically, if the car is plugged it, it actually WON'T charge the 12V. The 12V is only kept topped off when the car is NOT plugged in to a source of electricity.

I'd love to find the actual Tesla documentation on this, but I'm guessing it's a safety feature.
Personally I think this explanation is complete rubbish - the usual sort of nonsensical garbage we should all be accustomed to receiving from front-line Tesla staff by now.

Of course the car charges the 12v when it’s plugged in. There are ample stories from members here leaving their cars plugged in for months at a time, even a year or more, and they come back under normal circumstances to a fully functional car with a charged and functional 12v battery. The excuse Tesla gave James May was completely misinterpreted, or fabricated, or maybe both.
 

Eriamjh1138

Member
May 31, 2017
463
531
Michigan
Personally I think this explanation is complete rubbish - the usual sort of nonsensical garbage we should all be accustomed to receiving from front-line Tesla staff by now.
I agree. Total BS and untrue.

Tesla isn’t stupid about what to do when plugged in. That’s when all the diagnostics can be run and everything can be topped off.

The phone advisor had no clue and needs to be retrained.
 
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