Today i finally went through my first 12V battery replacement, at 77K miles, I am happy that it even got this far given a deep cycle battery type. will report when 100k miles.
How many months since delivery?
May 2016 production
I don't know if I'm more impressed with the battery life, or the fact that you have 77k miles on a MX!
Hmmmm, AGM batteries should last about 7 years on average. Doesn’t the main battery charge the 12v battery when neede?
Hopefully Tesla can figure out why your battery failed prematurely.
The 12 volt battery is a mystery wrapped in an enigma because we don't know precisely what sort of cycling it goes through so it is hard to know what to expect. But sooner or later it goes dead and probably at a most inconvenient time.
actually its not a mystery at all, normal battery in petrol car go through much less cycles when the car not being use, in ev cars, the 12v battery constantly drawing power to run the cpu, and stay connected via many electronics and must have precise power draw therefore goes through much much more cycles, battery's life is measure by number of cycles, now if tesla decide to use lithium 12v battery, that might change, otherwise, 18 months is pushing it.
In An ICE car, the alternator charges the 12v every time the engine is on, and while on, much of the electronics are powered by the alternator via some smoothing electronics. The tesla must use the main battery to charge the 12v, so there “should” never be a deep cycle issue as the 12v battery can be kept topped up at all times whether the car is in use or not? I would expect the 12v to last longer than in an ICE car. Even if the electronics are really pulling a lot more power when the Tesla is off than in an ICE car, there would be a few orders of magnitude of battery capacity in the main battery to keep the 12v in its sweet spot to last many years. Hope mine lasts a lot longer than 18 months!
Plus fact we are plugged in each day. Like a trickle charger on an ICE car. Battery should lasr 7 years. Less than 5 is a complete failure since we never discharge battery to death.