What vehicle do you drive?

Lambourne said:

No, it doesn't make any real world difference but cars are designed around the standardized emissions test and saving 5 CO2's in the test can make your car substantially cheaper in some markets. It's mostly there as a result of start-stop systems putting a higher demand on the battery.
The car's battery management keep tracks of battery age, cycles etc to optimize the charging pattern of the battery (bit like a smart trickle charger vs an older unregulated charger) and it needs to know if the battery is changed so it can reset those adaptations and know the correct capacity etc. The car will start just fine if you don't reset the registration but it will hurt battery life because it'll try to compensate for battery wear that isn't there yet.

It's been on many German cars going back to like 2000, earliest car I had that needed it was an E60 5 series. A scan tool is every bit as necessary as a wrench or screwdriver if you want to do much of anything on a modern car. Shit's complicated in all sorts of ways now.

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Interesting, I guess. It comes down to knowing your vehicles then. I vaguely remember the controversy around the stop/start system before, but never looked at how prevalent it is or what it all entails because I've not looked at or owned a vehicle that had it. From a quick refresher read, it sounds like a shitty system for locations that don't need it and is just another reason to keep/buy older cars (or sports cars that don't have it). With the main complaint that it puts more wear on the vehicle's engine and starter, in order to save a negligible amount of emissions that don't matter to anyone outside of California (in the US). I try to drive all my vehicles until they die, so I would actively look for vehicles that don't have it (or can permanently disable it), if I was buying something.

Without looking every vehicle up, for US manufactures, these feature are not on very many trucks until around 2019, nor on most of the V8 sports cars I saw. There are rumors the Mustang and Corvette might be getting the system this year. Strangely enough, the 2016+ Cadillac CTS supposedly has it, even though it has the same engine as the Corvette.

I also read that many manufacturers have or are starting to put in the ability to disable it, some temporarily with a button in the cab and some permanently through the computer. Dunno if it would effect how the system fucks with the battery though.

Furthermore, if I can buy a different battery than recommended for my car (but still fits, with close to the same or better CCA), for $40-$50 less, I doubt the stop/start inefficiently charging it would make it die fast enough where it's still not a better deal. For like half this forum, the Texas heat combined with the battery getting boiled sitting in the engine compartment kills batteries faster than normal anyway, so there is more value on saving money up front, instead of on the back end (for daily driven vehicles, at least).