Battery Summary?

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.planet-9.com/faq.php?faq=miscellan#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.planet-9.com/faq.php?faq=techdata#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.

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

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.

I put one in my truck but have not used it however the instructions say to let it stay plugged in for ten minutes or more. My understanding is that it charges the OEM battery enough for it to be able to start the car and is not an aux. battery for starting. I do have doubts about Black Decker stuff but this was an impulse purchase.

I followed the instructions when I tried to use it that first time - pretty straight forward & easy. All I can figure is that it needs to be fairly recently charged itself to work. I did notice that when I plugged it into the outlet, the lights in the cabin got a lot brighter. But it wasn't enough to start the car.

For those that leave your keys in your cars, can you please PM me your addresses so that I can come relieve you of your car? Of course that's assuming I can start the car since all you guys are draining the batteries.

I've left the car without starting/driving for up to three weeks with no battery issues.

Whoooaaaa, you went 3 weeks without driving your car??? I would be in major withdrawal...

Don't forget that if you leave the car sitting there and it is unlocked, it will drain the battery faster. It is another piece of that puzzle

Not true. From technical FAQ 2. It does not matter whether or not you lock the doors when you leave the car in storage with the key removed. The idle current once everything (interior lights, dashboard, etc.) times out and shuts down is about 15 milliamps (0.015 amps) - independent of whether the doors are locked or not. A heathly and fully charged battery should be able to easily support this load for several weeks without problems.

Based on this unscientific poll so far, the worries about the battery dying appear overrated.

As are most things. It's typically the stuff you don't worry about that jumps up and bites ya in the butt.

Eagle, it isn't the battery it is the owner. Take care of the battery and it will take care of you, meaning just follow the hints that you first posted to some degree or other. As we know there are no hard and fast rules that apply to every driver's use of the car but common sense will take care of any concerns.

Eagle, some of your points ... That's why I called it "unscientific". People will tend to complain but they usually don't run around saying "Hey things are great". It might be a small sample size but it's something. Trunk Clunk and other complaints. Every car has problems. None is perfect. Compared to other cars and forums I have owned and frequent, the Cayman has virtually no issues. So your trunk might clunk. So take it to the dealer and let them fix it. My last care had so many issues (not a Porsche) that it basically lived at the dealer. As they say "Stuff happens" Battery worries. I tend to have the same concerns, especially since it can get cold here and sometimes the car might not be driven for a few days. But I just don't care anymore. Yes, it seems the battery needs more attention. But, so what? If you leave it for a long period of time, throw the tender on it. I view it as the price I pay for owning the car. No big deal. If it dies, it gets a new battery. It won't be the first time I had to buy a new battery for a car and won't be the last. It's not the battery. It's the electronic draw. As people want more widgets and add more stuff, that little computer or whatever is always running. For example, I wish I could turn off the alarm but leave the car locked. The battery draw is the price you pay for owning the car. Bottom line ... if worrying about Trunk Clunk or the battery dying is going to stop you from buy a Cayman, it's your piece of mind you need to worry about. Maybe you shouldn't. It all depends upon what makes you happy.

One thing to bear in mind is that as the battery ages so its capacity to hold charge diminishes, it could typically lose 10% per year. After 3 years your 70AH battery could be down to 50AH, so whilst a new car may sit for five or six weeks and still start easily a 3 year old car probably won't. A few other things to consider is the more a car battery is discharged the more lead is shed from the plates (this is what shortens its life and reduces its capacity). Leaving a battery in a discharged state causes lead sulphate to crystalise on the plates which is very difficult to remove and reduces the perfomance of the battery still further.

Preserve your battery's like new performance I've previously posted the following on a couple other threads but felt due to the topic, it would be beneficial to our members therefore I pasted it below. -------------------------------------------------------------------------- I don't know how many of our readers are aware of this fact, but batteries begin their slow death from the moment the acid is introduced to the lead plates and the electrons start flowing. Every moment of a batteries life, it is producing sulfates and it is sulfates that ultimately short out your battery rendering it as "shot" or "dead". Recurring deep discharges or annually allowing your battery's voltage to drop ("get weak" or "go dead") creates much larger amounts of the sulfates to form more quickly on the batteries lead plates and precipitate like a snowfall to the bottom of the battery. If anybody has been driving for a number of years, I'm sure that they have once or twice inadvertently left parking lights, glove box door or etc. energized only to return to their vehicle one or two hours later and be surprised to find a "weak" or "dead" battery. You may have noted that the same battery (when new) would have tolerated such acts of forgetfulness with no problem but now that the battery is aging (sulfate build-up) it is losing its capacity. There is a wonderfully simple to install, inexpensive and peace-of-mind producing product that I use on my families, my business truck and my Cayman S (six vehicles). This device will preserve and extend your "like new" battery performance for double or triple the normal battery life. For just a fraction of the cost of a new battery, you can keep your battery cranking strong at "like new output", prevent the inconvenience of an unexpected battery failure and also protect the environment by saving all of the energy required to recycle/manufacture two additional batteries. For winter storage, just leave the Battery Life Saver installed and use any battery maintenance charger and a conventional household timer that cycles the trickle charger on for a period of time then off for the same period of time repeatedly. This will keep your battery strong as new for maybe a decade. Learn more at Battery Life Saver - Lead Acid Battery Desulfator . Regards, Joe

Ok folks, I'll take a crack at updating my initial post (by posting a reply here so we can see the differences) this weekend. If I get enough help from "youins" maybe it will be good enough for a sticky. Eagle

A FAQ entry would be better. An FAQ entry for here would be welcome All the help we can get on FAQs welcome

Consider it an 'anti-theft' technique after two days.