Battery dead after key was left in car

This isn't a complaint...maybe we could change the forum name to "issues"? I left my key in the ignition for two days in the off position and just found my battery completely dead. Only Porsche knows what the car was doing that whole time. No outward display of power usage was evident. Nothing was "on". Anyway, I popped my maintenance charge into a 12V hole and opened the hatch. Now I have the battery on my super-deluxe computerized charger. I selected 10amps...which is supposed to charge the battery in about 6 hours from where it is now. What should I expect from this battery now that it has been run down? Should I be doing a 2 amp charge? 20 amps? I am think of rigging a battery tender junior connector to the battery and plugging my car into the wall as a regular habit.

Oh Dave I feel so used. After we have warned about this so many times, you a frequent poster and reader went and did it ( Porsche even warns you in the manual on page 236 of the '06 manual)...but I'll give you credit for confessing. Also consider this from the manual "After the battery is connected or after an completely discharged battery is charged, the multifunctional PSM light lights up on the instrument panel and a message appears on the onboard computer to indicate a fault. This fault can be remedied with a few simple steps: 1. Start the engine. 2. With the vehicle stationary, perform a few steering movements to the left and right and then drive a short distance in a straight line until the multifunctional PSM light goes out and the message on the on-board computer disappears. 3. If the warnings do not disappear, then: Drive carefully to the nearest qualified specialist workshop. Have the fault remedied. 4. After the warnings disappear, stop the vehicle in a suitable place, and perform adaptation of the power windows. To do this, close windows once with the rocker switch. Press front half of rocker switch upwards again to store the final position of the windows in the control unit." Rapid charging can shorten battery life but I'd guess you will be o.k. if you take care of the battery from now on.

Always kick a guy when he's down. That's what I say. LOL. Lead-acid batteries don't live real long when they get drained to stone-cold-dead. But with the new technology, you should be able to jump and go. That alternator will have you up to full charge in no time. The formula is basically CCA/charge amps. So a 550 CCA battery on a 150 Amp charge will take far less time than 10 amps ...

fyi when the key is in the ignition the car remains ready to be started, so all the electrical c/u's in the car remain energized. The draw on the battery can be as much as a couple of amps, which will kill it fairly quickly. The car draws the least power when it is locked, and the alarm is armed. With those conditions being met, the draw on the battery (with no electrical issues present) is less than 30mA, which should keep your battery alive for weeks if not months.

I caught the part about needing to power the car via a 12V socket to get the hatch open in the front...a little credit is due here...LOL. When I plugged in the car, by the way, the passenger window and the interior lights went through a start and stop process until the passenger window was all of the way down. Once convinced that evil spirits were not in the garage, I hooked up the battery charger. Of course, my cargo area light in the front appears to have burned itself out. Now I have to perform some kind of ritual madness? Great. If you guys need me, I'll be out re-training my windows.

Dave the cargo light in front is controlled by a switch in the driver's compartment. Check that first. I could tell where but I want you to go on a treasure hunt and read the manual...

Santa Fe: Okay, so beat me with a wet noodle but I did the same thing. Left the key in. Problem is that the key is locked in the ignition. When I connect an external battery to the emergency connection as suggested, nothing happens. Well, not quite accurate, something "clicked" near the front of the car the fist time I did it, now when I do it absolutely nothing happens. Is this because the key is locked in the ignition? How can I unlock this thing so that I can get the front hood open? EZ

See your FAQ's here: Planet Porsche - FAQ: Indiosyncrasies Ignition key and Key lock. Boiling noodles...

Okay, so I am supposed to pry that little door open. Okay I'll try that. But what do you think about the reason that the battery release won't work? In the unlikely but of course possible option that I accidentally reversed the polarity of the battery I was using to attempt the release, what would that do to the car and how do I remedy it?

Might be time to check to make sure no fuses are blown, are we sure the battery being used to open the front is fully charged? And the proven procedure is "hook up the positive jumper to the red pull out post on the fuse box. Then use the chrome door striker as the ground for the negative. Use the front hood release remote button on the key to open the hood, not the release button on the rocker trim" and there is this "there is a mechanical backup cable release for the trunk lock. It is meant to be used if part of the electrical opening system fails, such as the solenoid, so it's not easy to access. You need to jack up the car, remove the left front wheel, remove the fender liner & you'll see the loop pull handle of the cable" but it may be time for 1-800- Porsche call, they tell me that this is their most frequent call.

Checked again... nothing blown. Yes, the battery was actually on another car.

Well, the proven technique isn't working. I applied the external battery exactly as you note. The problem with the manual release is ... the antitheft lug wrench adapter is in the front. I suppose everyone else has long since removed theirs to a safer place or replaced it with a normal lug. I did look under the front left and there are 2 obvious fender liners, one containing the vents and the other just above it. Which one is hiding the manual release lever? I could try to remove it without removing the wheel if I can contort a bit.

1-800- Porsche its free.

As as a soon to be new first time owner of a Porsche (whose family has owned everything from American, to Japanese, to German cars of all sorts, prices, shapes and sizes), when I first read this dead battery/hood release procedure, I thought to myself, "sometimes those damn german engineers just over think waaaaayyy too much" I understand about security and everything, but sheesh.

Santa Fe: It turns out that 1-800- PORSCHE had some good pointers. The absolutely best one is this: Despite what the book on page xxx says, do NOT put the donor voltage source (battery etc) negative wire on the door "U" bolt. It turns out that this is clear coated like the rest of the car and often does not make contact. Instead use the door hinge/pin which is not. Did this and bingo, the front opened like a champ. The second bit of advice was about the manual release under the left front fender. I was told that since each car is hand made, the LOCATION of the tiny loop is usually not taped in the same place behind the left headlight assembly. This makes it difficult to identify and inconsistent to find at best. I was advised not to go this route unless absolutely necessary. So now, I have another problem. After charging the battery back up, I have a PSM and PASM fault. They don't work. So I'll have to go searching the forum for info on correcting these.... If I'd only taken the key out of the ignition.... aaaah!!

Good data to add to our knowledge. Drive the car a few miles with left and right turns and I bet your faults go away. Let us know. Knowledge is power..

What's the logic behind capturing the key if inserted when the battery is dead? And why no manual trunk release in the cabin?

The faults all went away within 1 block. It's been like a dream since. But I guarantee I remove the key each time and lock it up (the lowest power drain mode) even in the garage. http://www.planet-9.com/images/smilies/dance.gif

I did much the same and drained the main battery. I was working on detailing the car and left the front hatch up. I noticed it much later and then shut it. And a day or so later, the remote key didn't work. Hmmm. Tried a second remote, no luck, then I remembered. Like the instructions said, I used the key to unlock the door manually, used a battery charger to pop the front boot and put the battery on a charger for about 2 hours. Then it started just fine. Got a few strange messages but they went away with driving. I'm more careful with doors and keys now. Ed

Something was on, the steering lock solenoid. Our ignition switches are completely electrical with no mechanical connection to the steering column like most other cars. So an electrical steering lock is used to lock the steering when the key is removed. For whatever reason, the boys at Porsche decided to leave the steering unlocked, which requires an electrical current be applied to the solenoid, until we remove the key. So if you turn the key off, and leave it in, the steering lock solenoid is still pulling current. Not a lot, but enough to kill a battery in a day or two. The next time you remove the key, listen for the click. This is the steering lock releasing (into the lock position). A lead acid battery doesn't like to be completely discharged. Typically, one that has been totally discharged will only recover to about 80% of it's previous CCA abilities. This may never be a problem for you if you don't use your car in cold climates. It's always better for a battery to charge with lower current over a longer period of time. But a completely discharged battery may not respond to a trickle (low current) charge until it's brought up a little from full dead. In this situation, I would start with a 20 or 40 amp charge for about 10 minutes, then drop to a trickle charge (<5 amps) for 8-10 hours. General rule of thumb is to not exceed 1/10th the batteries Cold Cranking Amp abilities during charging. So on a 600 CCA car battery, don't exceed 60 amps during charging. A 20 Amp motorcycle battery, keep it under 2 amps. Exceeding this will raise the risk of boil over or explosion. Never try to charge a very cold battery. Boil over or rupture is very likely. Always charge a battery in a place with good ventilation, and be very careful not to make sparks near a charging battery. Charging batteries release hydrogen and oxygen gasses, which are explosive. Always turn the charger off before disconnecting it to avoid sparks. Just like the steering lock, the key lock is also electrical. We need a key lock to make sure the key can't be removed when the key is on. Without electricity (dead battery) the key lock can't do it's thing.

So I left my keys in my porche boxter and drained the battery we have taken to battery wield and they charged it up again! The car starts but is now running rough! There was no problem at all with it prior to this and now put the charged battery back in and it’s running really rough.

The car "learns" while it is being used. When the battery is dead, it forgets this learning and needs to relearn. Try driving for awhile. Obviously if you have lots of codes you should have those checked out. PSM failure code is expected after a discharged battery and will go away after a little driving.