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Quick question. My battery won't hold a chatrge for more than 3-4 days in the cold undriven. It needs to be replaced as the alternator is pushing to keep it charged. Can the battery be completely removed and replaced without having to reset factory settings with a bosch hammer. Would it be wise to hook up a 120 volt charger to the cigarette lighter receptacal.

jimq

change the battery, reset the clock and radio do a DME reset and your good to go. DME reset is idle a couple minutes then a spirited drive or just start driving it and it will soon relearn its settings.

Marc Shaw

Don,

I unhooked my battery when re-wiring my stereo and it caused no problems.

Just remember to reset the DME by letting it idle for about 5 minutes then going for a spirited 20 minute drive to remap the DME program.

Marc

Marc Shaw

Darn - Jim just beat me to it.

Marc

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Thanks guys. Didn't know about the DME procedure, that was good to know.

jimq

I could delete my post Marc and then you could be first

MARC A. 964 C4

Don, Porsche makes a Trickle Charger, transforms current to 12 volt via the cigarette lighter, I had the same problems,..since then, never again!!

ARE YOU READY?...GENUINE ORIGINAL PARTS...980 611 980 00 .....in German, written on the paper grey box is: 1 LADEGERAET...You understand it's the size of a small transformer, and so easy to use, std. eqt. on the 996 AND 997 AND BOXSTERS, all those cars are dead the next day, too much drain, etc. Hope I helped a buddy! Ask Porsche, for more detail, and price...

Adrian

Dear Don,
In the area that you live I recommend if you are not driving the 964 to remove the battery completely. When you reinstall it the only thing reset is the DME so let the engine idle for a couple of minutes and then go for a drive to load up the maps that you usually use again. No stress.
I do not believe in using trickle chargers of any kind, under these circumstances. Having seen batteries let go when an unattended (often forgotten) trickle charger fails is not a pretty sight, despite all the built in cut off protection as well. I do not trust them suckers.
The part number that has been given for the Porsche one by the way is expensive. There are MUCH cheaper versions available in your homeland. The Canadians have some experience with a very cold climate and battery problems. I have a nice Canadian designed and built solar powered unit.
You also need to take care if ordering such toys from Porsche that you get a 110V version. Germany uses 220V.
The other alternative is to use the powered heating blankets after you replace the battery of course, if you intend to drive in winter.
Keep the new battery warm and it will stay charged. Ask me how I know? I helped install the battery warmer blankets in the entire Air Ontario aircraft fleet. -22 to -40C and the batteries kept warm worked like a charm.
My advice, remove old battery, cover the 964 in your garage, leave it, relax and go back after winter and install a new battery.
If you need to drive, replace the battery and install the battery warmer blankets that plug into your wall socket in the garage.
Ciao,
Adrian.

Pesty

Just a word of warning if you have LWF. I am having battery troubles at the moment you may remember the post.

Anyway I removed the battery completely to charge it up completely then took it to get it tested Guy put a load on it and said it was ok.

Put battery back on car then car stallled at every junction and would not idle. I had to start the car about 30 times (at least the battery was charged but probably is low now) drove it up to my mechanic where he plugged in the bosh hammer which sorted out the problem.

so i cant just unplug my battery because every time I do I will have stalling problems

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Thanks for all the feedback. Adrian, my daughter is buying me your 911 Enthusiast Companion Book for Christmas and I'm anxious to get my hands on it. I wish I could put the car away for winter but I won't be able to resist taking it out when the weather is nice. Not that I would have any reservations driving it in winter fulltime, I just don't trust the other 2 million drivers in Toronto that still don't understand the meaning of "black ice". Think I'll get a heating blanket.

Mark A., Pelican sells a genuine Porsche trickle charger for $68 US. Porsche dealers are selling them for $175 canadian per a friend.

Pesty, not sure what LWF means? Sounds like you have a continuous drain on your battery from your strater, just guessing.

DaveK

LWF=Light Weight Flywheel.

DarrylH

The dealers now sell two different chargers, the original is a little "wall-wart" transformer battery maintainer (CA$95 at Downtown Porsche (no affil)), and a larger battery charger that also has the maintainer function. The latter is the ~CA$180 one. I saw them both here http://www.eagleday.com/carcare2.html but bought the little one locally.

Indycam

Im not sure you have a bad battery .
You might have a battery drain .

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I checked the battery on a meter and it's showing only 239 CCA after I ran it for about 30 minutes to recharge it and the meter is showing the alternator to be putting out excessive charge. If there is a drain, it's not from any lights but could be from the aftermarket Alpine radio. I have a feeling it continues to pull a current after I shut down the car. I keep forgeting to check that out. Thanks

jimq

Maybe the infamous green wire behind the radio is shorting to ground.