car battery

Why guess-- test it. If it has removable caps, pick up a specific gravity tester for a few bucks at the local auto supply store. The kind with the floating balls are cheapest and accurate enough for a keep/replace decision. The ones with the calibrated float are only a bit more money and give a more precise reading if you're the kind of guy who likes that.

Or get it load-tested. Most places will do that for free-- AutoZone, Pep Boys, NAPA, etc. -- maybe even your dealer.

Make sure they use the right test load though. My OEM battery has a sticker on it that says to test it around 200 (I forget the exact number) but my dealer tested it at around 400-- which is the more common test load-- and told me my battery was bad.

I doubted that and tested the specific gravity myself which was fine and then took it to two different auto stores where it also tested fine.

Basically I did test it and it was borderline. I opted to replace it. Manager told me that the lack of use did degrade the life of the battery too. Of course it's no exact science.

The battery in my ancient 1956 Studebaker is about eight years old and is still good. This car gets very limited usage but is driven occasionally.

Conclusion, no single answer applies. Some batteries last longer than others for whatever reasons..

JT

They can last very well. I replaced the original battery in my regularly used 1999 Peugeot 406 diesel last year. I reckon 11 years is pretty good. Even then it didn't fail but I was dubious about it getting through another winter.