What is average lifespan of a battery?
 

My '02 S had an Interstate battery installed in 2013. Over the last few months it's been losing charge more and more, and the Battery Tender I use became more of a necessity. A friend was storing the car for me the last month or so, while I did some major home improvement stuff. I didn't know he didn't have a Battery Tender of his own, so the car sat without anything helping keep it charged up.

Yesterday when I went to collect the car, it wouldn't start. We jumped it, and it started normally, but after turning it off an hour or so later, it wouldn't start again. Thinking the battery was just extra-low, we left it on a charger all night. Today, same issue - no juice. So now I have a brand new battery, which I will monitor the performance of.

The question for you experts is this: What's the average lifespan of a battery? I live in the Pacific Northwest, where temperatures rarely get too hot or cold, and batteries in my other vehicles seem to never fail.

What's your experience?

Dave

I had an Interstate battery last 7 years, it could have been longer since it came with the car. And that is in temps from 0° F to over 100° F.
However, I think the average is more like 5 years.

Average lifespan means nothing.

Some batteries fail within a year, some last to the point that you replace them because you don't trust them anymore due to their age.

Personally, I've had one last less than two years and one make it 9+.

Bottom line is it sounds like you have a bad battery. Replace and enjoy your car.

The interstate battery in my 2001 boxster base lasted 10 years, but I'd say anything in a 5-10 year range is good.

A good way to cause them to die an early death (as it seems you've learned, unfortunately!) is to leave them in a fully discharged state for very long. This can cause lead sulphate crystals on the plates (always present when discharged, but usually small), to grow to large crystals, which reduces the surface area of the plates exposed to the electrolyte (reducing cranking current capacity), and which cannot be removed by a normal battery charging process.

The normal failure mode on 12v automotive batteries I've had is when the cells becoming unequalized, or have uneven current leakage such that the cells just can't be practically maintained in a satisfactorily enough equalized state. The unevenly charged cells (six cells wired in series on an automotive 12v battery) result in the inability for the battery to get a full or satisfactory charge.

I picked up a nice AGM battery for my 2001 boxster recently here in Seattle area locally. It's a bit heavier than conventional flooded battery the same size, and costs a bit more, but I've been very happy with the performance and fit. I've had very good experiences with other AGM batteries in several other vehicles. 8-10+ year life would be my expectation. Details here: http://986forum.com/forums/516919-post12.html.

Last car I had to replace a battery on didn't have an OE-sized AGM option available, so its nice that we have battery options for these cars!

I've had (cheap) batteries fail after a year, and some (expensive) ones that never seem to die after 7-8 years. But it's all just an exercise in basic math.

To determine the life of a modern battery, simply subtract the month/year purchased from the month/year of its demise.

The resulting number should match the lifespan warranty of the battery. If the number is lower, then you can prorate the cost of the battery on the purchase of a new one. If the number is higher, you did good, real good. Buy the same battery again.

Just sayin'..........

TO

An Interstate battery should last a lot longer than that unless its lived a very hard life.

Battery life is a totally open ended question. Batteries die because of how they have been used, the climate they operate in, parasitic drains of the car, condition of the car's charging system, etc. They can also suddenly succumb to internal shorts or component failures, sulphation, etc. We have seen them live happily for 12 years, or die in 2 years.

Depends a lot on whether they're kept charged or suffer from long periods on non use.

If the latter occurs, put a charger on it at the outset.

Because my 98 Boxster is a summer "Sunday Driver" (never sees rain or snow) I keep mine plugged into a Battery Minder (a battery maintainer) 24/7 when I'm not driving it. My Interstate battery is 7 years old and still going strong. I have Battery Minders connected to all my vehicles, other than my daily driver.....at about $35-$45 each they're a lot cheaper than batteries and I think they do a great job.

How long is a piece of string?

In my case..
 

I've had an Interstate for almost 9 years. I keep it on a Porsche battery tender when the car isn't being driven. (It's really a CTEK, but because it says "Porsche" on the front I know it works better.)