On June 28 the car would not start (4 month old 987 S, 1400 miles) - it was in the garage unlocked and was driven 6 days earlier. And nothing was plugged in, left on, etc. It had sat for longer beforehand and never had problems and is always driven for at least 30 minutes when taken out. Roadside Assistance towed it to Brumos and they replaced the battery - told me to buy a battery maintainer but I did not since the car should be able to sit for less than a week and start.

Same thing happened yesterday, July 5, and it was last driven June 30 after the 65 mile drive home after getting the new battery. This time though I locked the car when I got back. I had to use the key to open the door and as the last time, no dash lights, no crank, nothing. So it got towed to Brumos again and hopefully tomorrow they will figure out what is causing the batteries to die, which again just started happening.

I searched the forum but did not find any help although others have had similiar problems, but not twice in a week!

If someone has suggestions please post and I will update based on what they say; however, I will not settle for another battery replacement nor will I buy one of their battery maintainers since I drive the car at least once a week - this is unreal.

There are quite a few threads on this topic. The car should be able to start after sitting for a week, but usage plays into this. Do you drive it for 30 minutes once a week? 3 hours? If you only drive it a short period of time, you won't put enough of a charge back on the battery to replenish the drain from it sitting still. I would recommend, albeit against your advice, to get a tender. This would at least give you the ability to get to a 100% charge. Note however that a battery tender will not function if the battery is completely drained.

There is a thread around here where a member measured the resting load on the battery. You may want to see if you can measure yours against his results, and see if something is out of whack.

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"The Cayman doesn't need any more toys." -- My wife

He did mention that he drove it 65 miles (say 1 hour) from the dealer . . . should have been enough to sufficiently charge a new battery IMO.

Doesn't sound right that 2 new batteries wouldn't hold a charge more than a week - assuming you didn't leave your lights on or something like that. I can't think of what else would cause them to discharge prematurely though - maybe an alternator problem?

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My Blogs
2006 CS Tip (Daily Driver & Part-time Track Toy)
2005 Ford Expedition (to haul the CS)
2006 Lexus RX400h (wifey's)
Gone, but not forgotten: 2002 WRX, 2004 MINI

About battery tenders; Although the Porsche battery tender maintains a battery in charged condition, it will not charge a dead battery. There are tenders out there that will. There is a tender from Italy that maintains the battery as well as charge it from dead status. Brand name Polar.
Disclaimer: My company is involved in testing, evaluating and probably eventually marketing the Polar tender and charger.

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formerly cebotech1

Go to your local VW or Audi dealer they have the best battery tenders (solar powered) it even works in your dark garage, crack the blinds a little to let some light in. My car sat for 3 weeks and it kept charge. You can even find them on ebay. It came with my audi and jetta back in 01 so I have 2 of them. They leave them on port with those on the window. BETTER THAN ANY BATTERY TENDER ON THE MARKET IMO!!!!!!

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Cayman GT
369BHP 325LBSTQ
313WHP 276WTRQ
some people like the regular stock factory look, cool people modify the car.

I have one of these lying around but never used it. 2 Questions
1) Can you quantify how well does it work in a dark garage
2) Is it advisable to plug it in Porsche i.e. specs match ?

1) I have been using it for 2 years I put about 6K a year on the car.
2) I havent had any problems. It uses a standard 12v outlet on cars.

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Cayman GT
369BHP 325LBSTQ
313WHP 276WTRQ
some people like the regular stock factory look, cool people modify the car.

I had a similar problem, with my '08 C2.7. I was sure it wasn't the battey since I drove it everyday and I had only had the car three weeks or so. Further investigation revealed that the bolt where the battery ground wire attaches to the frame was just a little loose. I tightened about half a turn and haven't had a problem since. Afterward I wrote about it here and Suneet informed me of a Porsche note indicating some '08s may have shipped with this problem.

There is a TSB on that issue. It usually has to do with the car starting, but could very well apply to this. You can get the actual TSB from renntech.org, but your dealer should be able to find it and fix it for you.

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"The Cayman doesn't need any more toys." -- My wife

Got the car back today - they put in a new battery after determining it was bad - they said it must have been part of a bad batch (covered under warranty again). I also got a battery tender but plan to let it sit in the garage/locked for 6 days to test it out. Again, the car should be able to sit for 6 days without a battery tender and still start, just like it did for the first 4 months I owned it. What about the people who use them as daily drivers and park at the airport for a week long trip?

So,,you are happy with Brumos?
I purchased my 07 2.7 from them and have yet to have any issue with it. Except the trunk clunk which I will deal with at 10,000 miles.
Had a battery problem several years ago with my x wifes car. Somehow a cabin light got switched to the on position. Noticed it one late night in the garage.

Bob, that is insane. Return that damned maintainer, there is NO excuse for a car to not be able to sit for a week without the battery draining!

FYI, I've left mine sitting for two weeks before. Got in, it started right up.

My cab lights stay on unless the alarm is set and boy do they get hot. Battery has not died yet . Maybe you have a short or an open cicuict somewhere. Seem like your warranty would cover it. If not 3 times the Lemon law get another one!

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Flyboy