These days, car batteries last a lot longer because the ECU is a far better charger than the old voltage regulator.
my 25 YO car was not designed to only be driven 17 miles, once a week. The ECU (including a misbehaving OEM alarm system) puts a constant drain on the battery. My 17 highway miles are not enough to top off the battery after two or three starts. I can see with my smart charger that it goes into de-sulphation repair mode. I leave the charger connected 24x7 and it isn't smart enough to supply enough low level current to prevent the battery weakening, but it periodically shifts into repair mode.
In the old days, a dying battery faded out slowly. The last car battery I replaced, still provided 12V, but the ECU refused to provide voltage to the starter. Of course, I doubted the ECU's judgement, but it was right. Despite still providing 12V, the capacity was too low to crank the engine AND provide enough juice for the electronics. It lasted six years, so that's not too bad.
Another advantage is that the starter motor will last longer too.
That reminds me of my starter motor story... I have messed with cars since I was a yout so i am pretty familiar with automotive symptoms. Back last century the starter motor for my current car failed. I was still working at Peavey so didn't have much time to wrench on my car. I didn't trust the local ford dealer (thats another story***), but the local Lincoln/Mercury dealer was OK******. I parked my car on a slope so I could jump start it. I drove over to the Lincoln/Mercury repair shop and told them I needed to get the starter motor replaced (not trivial in this car the large engine needs to be unbolted and jacked up out of the way. The head mechanic came out and told me to shut off my motor, so he could test the battery (his diagnosis). I told him I would, but the car would not start again. He measured the battery and was surprised that it measured good (meaning I was correct). I had him give me a push so I could jump start it one last time and pull it inside his shop.
And, no John, I don't need any more batteries. But thanks for the offer
Both driveway lamps were still lit at 6AM this morning so I think I can stick a fork in these for several more years. It stands to be seen if these can deliver the 2000+ cycles (almost 6 years).
[edit- a perhaps final update on this, the lights were still lit, pre dawn this morning, despite yesterday being overcast and raining. It looks like the extra battery capacity is useful. /edit]
JR
*** I lost trust in the local ford dealer when they botched a simple tune up. I paid them to swap out my spark plugs, but noticed a misfire after a few days. I popped open my hood during my lunch break to check for a loose spark plug wire. When i was a kid pumping gas I fixed at least one car that the day time mechanic didn't seat the spark plug wires completely. This time while checking the wires, I found a spark plug that was only finger tight. I unscrewed it and could see that the electrode was burned up from overheating. The spark plug is kept from overheating by transferring heat to the head, being loose it over heated. Since there was a car parts store within walking distance of my office, I bought a new plug, and borrowed a spark plug wrench from one of my coworkers. I drove over to the ford dealership to give the service dept manager some useful negative feedback. When I showed the manager the burned up spark plug, he said it looked like "water damage"
. Then he offered to give me a new spark plug... I said no thank you, but have heard other similar horror stories.
***** The better Lincoln/Mercury service department was not without issue. After my car was repaired and I went to pick it up. They couldn't find my keys. After a little scrambling they found my keys in one of the office worker's pocket. He had apparently needed to take it for an extra test drive.
Most of mine see very little use these days. I just wish I could find a set of 9V blocks that are really good. The best ones so far came from a US company, but they aren't cheap. Add shipment cost and buying a dozen or so is way too expensive. I can't find them over here. I'm sure there must be good ones out there, but as I don't buy large quantities I can't tell them apart.
