So, I've read most, but probably not all, of the threads about dead and dying batteries. From what I can figure out, here's the summary:

1) If you added stuff to the car after you purchased it, like an alarm system or fancy-schmancy stereo/Nav, be careful. Investigate this first if you are having battery problems.

2) You cannot leave the car sitting in the garage for more than about 5 days, or you risk the battery draining to the point where the car will not start.

3) If you're going to leave the car sitting for more than 5 days, put it on a trickle charger. Any reputable brand will do: the Porsche variant is not required.

4) If the battery dies without your knowledge, and you insert the key in the ignition, it's stuck there until you charge up the battery.

5) You need to drive the car at speed (> 45 MPH ?) for more than ~ 15 min to get the battery charged.

If anyone knows any of these are wrong, or thinks something should be added to the list, please post it. As someone who has "searched" and tried to accumulate information on the "dead battery" topic, it would be nice if it was all in one thread (maybe this one, or if Ken or someone wants to make a sticky). I think this is a bit like the "trunk clunk" issue in it's popularity, and should also have been a sticky, IMHO.

Eagle

Agree with all your points.....especially the trickle charger, it's amazing how a little item such as this takes care of a bunch of headaches.

There is a solution to #4. See the Faq's here: http://www.caymanclub.net/faq.php?fa...llan#faq_idios (ignition key)

There will always be antidotal exceptions but I think you hit the nail on the head.

From my own experience:

6) If you leave the key in the ignition after turning off the motor, it will drain the battery to the point of needing a charge within 1 to 2 days.

The car comes with an alarm. Has anyone actually added an alarm on top of an alarm

Ancedotal data only that you cannot trust as characteristic of the set of cars sold as a whole. As others may have had isuses, I left it for 5 days with no issues. That might be a good poll. It's just something to think about, but not necessarily something to worry about.

Not true. A trickle charger is NOT what you want. That is old-fashioned. Porsche version (AKA CTEK) is far more sophisticated and conditions the battery. Google around to learn the difference.

I'm not believing that one entirely either. There may be many variables here but my wife might take under 15 minute drives, at times during the week. I got "worried" about this because of the somewhat paranoia about battery, stuck the battery tender on it and it was charged within 30 minutes (considering the rate of charge meaning it was basically a fully charged battery). I think cold weather has a LOT to do with this and there is no hard and fast data but that's my experience.

You know that old saying about don't have a new idea because you might get stuck actually doing? Feel free to writeup a FAQ on it and we can get it included into the existing FAQ. The answers, however, need to be factual and not just ancedotal data by a few people relating their experience. I believe we just added some factual battery drain info in the FAQ here http://www.caymanclub.net/faq.php?fa...#faq_batterysp

Care tips from the manual.
"A well-charged battery prevents starting problems and has a longer useful life.
Traffic density, speed limits, requirements regarding noise, exhaust gas and fuel consumption reduce the engine speed and, hence, the generator output.
However, the large number of electrical loads has markedly increased the demand for electrical power.

In order to avoid unintended battery discharge
Switch off unnecessary electrical loads in city traffic, on short trips and in queues.
Always withdraw the ignition key when leaving the vehicle.
Avoid frequent operation of the Porsche Communication Management system when the
engine is not running."

False. I just got back from a vacation and the car sat in my garage for 10 days without being driven. Started up normally when I got back with no problems.

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Brian

I'd go with this, I've left the car for a couple of weeks without being on a charger and had no problems. Battery is only about 5 months old though

There are so many variables that there will be all kinds of examples but the OP said "risk of" and he is probably correct on the very conservative side of things (starting with a battery in a low state of charge, very cold and so on.) Just be aware that taking care of the battery is as important as taking care of the tires and there are a lot of people that might forgot how important that is until too late. Porsche Emergency Services relate that battery failure is the number one issue they deal with.

Exactly. Too many variables to give factual data.

This happened to me as well. I left the key in the ignition for over 24 hours. It drained the battery and the car, although not totally dead, would not crank without a jump. I was all excited to use my nifty black & decker battery booster, you know the one that fits perfectly in the little storage compartments in our beloved Cayman....

Simple Start Auto Battery Charger from Black and Decker

Big negative to answer the obvious question, did it work? I had fully charged the booster but it had been a while (a few months). The booster turned on and the indicator lights looked ok but it didn't have enough ump to start the car. Guess it needs to be charged more frequently.

That's interesting - I have one of those too - now I'm wondering if it has enough juice to start the car even when it's freshly charged.

Has anyone used one successfully?

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