Simple. The cars that have needed new batteries were bought used, had the factory 12v battery still and went 4-5 years in both cases. No special treatment given to achieve that lifespan either.
Now you want to say ICE and Tesla in the same breath in terms of 12v lifespan and reliability? They're not the same nor are they even used for the same task.
In an ICE application, a 12v battery needs the amperage to crank an engine in all temperature conditions. This is a HUGE strain on batteries and why one of the biggest selling terms is how many CCA or Cold Cranking Amps that particular battery has. Without enough CCA you can't start your car. This number weakens over time with use and is greatly affected by temperature and weather conditions. Comparatively, Tesla uses the 12v battery only to power the low-volt (12v) accessories. The demands for amperage are so much lower that the battery isn't stressed as much and Tesla can more closely monitor it's life expectancy via voltage and more accurately predict when it will fail given how linear the needs are in a Tesla system. The way they keep the battery charged is drastically different as well and therefore produce different results in terms of life expectancy. I could go on and on but you don't care that the two applications of 12v batteries between Tesla and ICE cars is fundamentally different so, why bother?
There's also a very important difference between Tesla and ICE cars in terms of 12v batteries: Tesla will TELL you well in advance that your 12v battery needs replaced. You'll get an error message and will quite literally have months to replace this before it's dead enough to actually stop working. This is dramatically different than my experience with 12v in ICE cars which tend to let you know your battery needs replaced by not starting on the first cold day of winter potentially leaving you stranded somewhere. You're trying to scare people into spending more money but the fact is that you're getting dangerously close to why Tesla doesn't even need them in your chief selling point which I've outlined above.
This isn't how Tesla works so pedal your snake oil somewhere else.
In fact, if i didn't know any better, many of your claims come from someone who doesn't even know how these cars work from a fundamental level which leads me to believe that you are receiving some sort of kick-back by passing this info along as an "owner" with first hand experience on evil 12v batteries.
I’m not receiving any “kickback”, just trying to help others understand their options. I did not insult you so I don’t know why are insulting me or using phrases like “snake oil.” Uncool. However, I do “pedal” when I ride my bike. I don’t “peddle” anything here or anywhere else.
I know ICE cars use their batteries differently and keep them charged up vs Tesla’s “deep cycle” route. (That makes batteries in Teslas wear out faster, not last longer, by the way.) My point was that lead acid batteries do not last very long in Arizona’s heat, even with the gentler cycling of ICE cars.
Given Tesla’s common refusal to share any maintenance history with second owners, I’m not sure how you know that you were the first to replace the batteries, but, even if you could be sure, from my reading of this forum, yours would be the edge case, not mine or all the others.
Teslas
should give a 12V warning, but as we read in many situations recounted on this forum, that does not always happen. (I’m not sure where you have seen people getting
months of advance warning — the most I’ve seen on this forum are days and many virtually no warning at all.) Even if you had a warning while on a road trip, you’re still not getting home without either being stranded or relying on finding a service center able to help you with both an appointment time
and the correct battery in stock.
Unlike an ICE car, if your Tesla’s 12V dies, you are
stuck: can’t get in the car, can’t get in the frunk, etc. If you have the misfortune to suffer a 12V failure overnight during an update, you might be
really stuck! Where a new 12V battery doesn’t solve your problem at all. You don’t have to look far on this forum to see those tales of woe. I haven’t seen what Tesla’s out-of-warranty charge might be for rescuing a broken update but I know the tow bill alone will be more than Ohmmu’s price difference. God forbid it hastens an eMMC demise!
Out-of-warranty is another issue, besides reliability, that you’re not considering. As early Tesla adopters and their cars age, we have to pay all the repair and maintenance costs. $250 every 18 to 24 months in Arizona or $420 48 months or more? Again, the money savings for me is just icing on the dependability cake.
In closing, I’ll repeat: I hope that you continue to lead a charmed life where you never get stranded. I wish you well.