Start stop systems on non-hybrids may decrease agm battery life

Yes it is the same thing BMW and Porsche and lots others have done. I wouldn't be too worried about decreasing the life of the 12v battery in those vehicles. Remember as a preventative maintenance item they should be replaced every few years anyways.

The real question is if it helps at all. The answer in the US, is almost always no. Here people creep up to lights, then creep along a bit, and then a bit more, and then a bit more. It is like if they get closer to the intersection, the light will turn green. It is ridiculous but happens everywhere. In this situation, the engine will not be able to shut off. If you drive where you stop and then stay stopped even if the car infront of you creeps up a whole car length, then maybe it will help a very small amount. But to move, the engine must be on. The beauty of the Prius is that during these creeps or low speed deceleration, the engine is off. Really these start/stop systems help very little and all they do is perpetuate the myth of slow and annoying hybrid technology.

When your engine is stopped and you floor it, there is extra time for the engine to come back online. Also there is no way to prevent the vibrations of the engine starting and stopping all the time. In the Prius it gets spun down gracefully, and you can still feel it. In these cars there is no spin-down mechanism, it just stops so the car will jerk. Now it happens every time you stop and every time you start?

I can't see this ever selling, and those that do buy it will complain and force people away from better implemented systems.

 

The energy needed to crank a warmed up healthy engine doesn't approach what I'd call deep cycling.
You're stringing a bunch of "mights" together in your posting and concluding that you don't want the feature. I don't recall hearing about any problems with such a system (and they've been around for several years in some cars).

 

The info for the TTAC article comes from Pacific West, which appears to be a bank or securities company. The info might be biased.

Not all start-stop systems are the same. Mazda's puts little extra strain on the battery. They use injector finessing to start the engine. If you also opt for their regenerative braking, you get a super capacitor with a battery backing it up.

The more traditional start-stops should have a beefed up alternator. Considering a standard alternator doesn't really do the job of a battery charger, it's possible these systems aren't fully recharging battery between events, and the deeper the discharge, the shorter a lead acid battery's life.

I FAS my cars, and try to top the battery off with a battery charger regularly now. I didn't at first, and a 6 year battery may have lasted only 5 because of it.

 

Never been a fan of start stop technology in a non hybrid. It's a nonsense idea and will put massive strain on the 12v battery, however 'uprated' it may be. It's winter, your lights are on, your heating is on, you have the radio on and you're in start stop traffic.

The 12v isn't going to last 12 months in that environment and the opportunity of having the 12v fail to start the car up again will be high a year or so.