What's your average battery life for your 996?

I find my 996 C4S to be a reliable vehicle most of the time. That being said, it seems to be really hard on batteries. It's not a garage queen that is rarely started - this car is my daily driver. This morning, I went out to the garage to start up the car to go to work and the battery didn't have enough juice to crank the engine. It was just driven on Saturday and it didn't have an issue. My batteries seem to last for roughly 18 - 24 months. Is this normal? Perhaps I have a failing alternator or a slow power drain somewhere... My Cayenne is also hard on batteries, but it's not as bad as the C4S.

Dammit Dennis you jinxed me! I was thinking to myself how I've had good luck with mine. But of course mine died in my parking garage at work. On my way to buy a new battery now. Anyone know the sizes of the nuts on the terminals and the one in front of the battery? I want to make sure I have the right tool sizes.

I had my original 2003 996 battery go after 9 years...was hoping for 10.... It's plugged into a battery tender when not in use.

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The posts are 10mm, sorry can't remember the size for the bttery clamp

What brand of battery? I use the porsche battery and get 3 - 4 years out of them in the hot Florida weather and drive it somewhat seldom. My garage swears by interstate batteries

I've always used the Porsche branded batteries from my Porsche dealer. I think it might be time for me to consider another brand. Mine's connected to the smart charger now. It only registered 10.6 volts when I connected the charger. It's up to 14.7 volts now. Hopefully it just needs a charge and then it will be good for a little while. I last replaced it on February 6, 2013. I'm not sure how long the warranty lasts on a Porsche battery, but I think it may only be one year.

Dennis, a few things to check. What does the voltmeter or the one in the cluster read when the car just started, at idle and at speed? Say with low beam and a/c ON? If it's 13.5v to 14.5v, then it's likely your charging circuit is fine. Typically they last at least 3-4yrs. If driven daily, they could last 5 to 6yrs. If the charging is fine, most likely you have a parasitic draw. Any aftermarket electronics on the car such as amp, radar detector, lojack, etc?

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Sorry but that doesn't count A lead acid battery doesn't deteriorate much if it's fully charged all the time.

The volt meter in my cluster typically reads right around 14 volts when the car is running. I have noticed that right when the car starts, it tends to drop down into the low 12 volt range, but it quickly goes up to the 14 range after that.

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Do you have any problem starting the car if you leave it parked for say 10 days or longer?

I don't think it has gone for 10 days without being started since I've owned it. The longest that I recently let the car sit without starting was 7 days, and it started up without any issues.

The longest I've let either of my 996s sit without being driven is about two weeks (on a couple occasions). Both fired right up after sitting that long. My car regularly sits for at least 5 days, with doors locked and alarm on and I've never had a dead battery.

I hope this isn't a jinx topic. I am at 7 years on an O.E.M. battery in the C2 and never had a problem as a daily driver for 5 years and it still seems strong although it is driven only a few times a week. I have never used a battery tender and we do see extreme temps here in both winter and summer. Oddly I was just thinking about replacing it as I really didn't expect much more than 5 years out of it. The battery in the C4S is also O.E.M. and about 3 to 4 years old with no issues. Both of my cars do show a voltage drop immediately after starting but quickly rises to 14v plus then settles in at what looks like about 13.5v.

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If you have a low current DC amp clamp, it's super easy to check parasitic draw. If not, I would consider non OE batteries such as costco, interstate, duralast, etc.

I had to change my bought new Diehard Platinum out at 3 years +/-.

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The clamp is 13mm. Thanks for the answer!

Despite multiple hours on the battery charger, my battery is dead. Again. I'm going with an aftermarket brand tomorrow instead of the Porsche/Moll battery.

I have had my 03 Targa for 7 years now. When first bought in 6/07 it had a non Porsche battery installed at a Denver Porsche dealer. In 6/09 I took it back to the dealer because the car could not sit more than two days or it would not have enough charge to start the car. I had to change the battery again in the summer of 2012 and this time went with a Sams Club Energizer size 42. This summer I am again seeing the car not be able to sit more than a couple of days without needing a charge before starting. I may need to replace the battery for the 4th time in 7 years. No special accessories installed and I lock the car with the key when I let the car sit more than a day. I drive the car from May to November at least weekly and take the car out on winter days at least once per month. I usually keep the hood un-latched and put on a 2 amp charger every weekend during the winter. I did use a trickle charger from Harbor Freight one winter but I was not sure that was good for the battery. I guess I need to spring for the Porsche quality charger. The Sams battery should have a 3 year warranty. John

I average 3-4 years from the OEM. I went through 3 of those before switching to a Diehard GEL and haven't looked back.

Dennis, I replaced a dead battery in 2008 with an Interstate battery, so 6 years and still working fine in my 99' C2 Porsche. I have a battery in my center console boat that is original from 2001.

C'mon!! I don't think there really is any mystery here...any typical car battery will need to be replaced after 3-4 years. Doesn't matter the make, model or whatever. It's a throw away item. Cold is a battery killer and so is heat. My daily driver 99 996 C2 w/130,000...replaced old 4 year old DieHard battery one year ago with DieHard AGMG Group 48. Drop and drive....never misses. Very happy with my choice and there is a Sears just about everywhere you go. Paid (w/tax) $187.96

I would be really happy with 3 - 4 years of battery life as opposed to 1 - 2 years!

3 1/2 flawless years on a Walmart Maxx battery that is made by Johnson Industries same as Interstate. It looks and weighs the same as the Interstate except the stickers. Thought I'd give it a try as it's easily returned and only $70... so far so good!

My local dealer did the right thing. They tested my battery and diagnosed it with a bad cell. The battery is being replaced with a new Porsche battery at no charge to me. I'm pleased with the outcome.

You can't beat free! Happy to hear you got it sorted out. On the road again....

Congrats! Does the warranty restart for this new battery? If so, you're just gonna have free batteries every 2 years from Porsche

The new battery does have a new warranty!

Geez guys! 6 years on a battery? Cheap bastards! LOL

Pep Boys has the Bosch 49-850B for $177. and offers a 25% discount for online orders. Order it online then pick it up at your local Pep Boys for $132. plus tax.

http://goo.gl/ogAOGN im not a fan of autozone, but my battery on my truck dies will "die" about every 3 years or so and AZ replaces it for free each time. I havent bought a battery in over a decade for the truck...I plan to do the same with my 996 when I have to finally buy a battery, I am sure that it will be the last battery that I will ever have to buy for it.

Thanks for passing on the battery curse guys! My beloved 996 has been sitting in my office parking garage awaiting a new owner. I was on vacation for 2 weeks and of course, the battery was dead when I returned (no nearby outlet for a trickle charger). The battery is less than 3 months old. Jump started it (took a looooong time to turn over) and drove it for about 15 minutes. Voltimeter registered close to 14. Turned the car off when I stopped to top off the gas tank. Started but was a bit sluggish. Drove back to the garage shut it off and tried to start again. Started but was even more sluggish. I doubt it will start on Monday. How long does it take for a battery to get back to full strength?

Depends on either how much you drive on the highway or how many amps your charger is rated for. Best bet is to drop it off at Autozone in the morning and pick it up in the afternoon. They have a commercial charger and do it for free.

Once the battery has lost charge it is a steady down hill slide. Unfortunately they can't make up that loss...you eventually need to replace it.

All new cars have computers that need power. The more they sit the more likely they will go flat. If a battery goes compley flat for 3 days, it will never recharge. So keep that in mind.

Correct I find if I am not using the car for a extended period of time I have to put it on a trickle charger or I run the risk of it being completely dead when I go to use the car ,,,,,I generally get around 2 years to a battery using this method ..........

Gonzo, Id be looking at my alternator if I was you.

In 12 years and 70K the car has had two Porsche batteries and now an Interstate. So... Roughly 4 years a battery. No trickle charger and driven at least weekly. Nothing abnormal compared to other cars that I have noticed. My long-time shop strongly recommends Interstate over other brands. When I went with an AutoZone battery in my 968 it lasted less than a year, and that car was a daily driver.

I think my battery was shot at around 3 years old ... car sits for 5 days or so between runs (a lot of the time) and if I leave it longer than this - cranks real slow. I put it on trickle charger if I know I will be gone for longer than this. I just replaced with Sears DieHard Gold AGM 94R (H8) battery - fits well - I want to see how that does after sitting for 5+ days - I'm expecting it will be much better - but let;s see. One note on fitting new battery - vent hole is hard to see on side of battery - and it has holes on two sides. I connected the vent tube to the positive side - but need to go find a plug (I think) for other side. I guess I didn;t look hard enough at old battery to see if it had plug on the spare side when I recycled the core.