Battery maintenence techniques

I'm looking for some suggestions on how to keep my battery in working order. I just toasted an Optima Red 34/78 after 5 months because of my lifestyle. I live in a very urban area, don't get to use my car much, particularly during the winter. I garage it in a pay garage a few blocks from me. There's perhaps 1 or 2 outlets in the garage, and only a few spots that have partial sunlight. There's also no guarantees I get one of these spots when I park. I have gone 3+ weeks without driving the car, so I need to do something to keep the battery in working order, especially in the winter. Anyone have suggestions for me?

Your solution is obvious. You will have to move to California and drive the car in warm sunny weather everyday! AA

Many of my cars, including Porsche will sit for 3 - 5 weeks in 40F- temps and have no problems starting. Get a battery with the correct reserve power, like the stock size one. Other than that, just stop by every couple weeks and let it warm up fully.

i am planning to do that now. hate the single degree cold in NJ. guess the global warming is not lasting as long as i wished?

I have an Optima Red Top and it's superior to the stock battery in every respect. When my car sits for long periods of time though, I hook it up to the Porsche Charge O Mat II.

What do people do who live in high rises? My home in the city is a condo. Secure underground parking (yay). No electrical outlet for a battery minder (boo). I haven't driven mine for four weeks or so. Judging by the interior lights, I think the battery is fading on me. Not to mention the tires weren't aired up for storage. Not to hijack the thread, but how do you cave dwellers manage?

I have to assume that while you were observing the interior lights, you also started the car and ran it for 20 - 30 minutes?

Ah, no. I'd rather replace a battery than let my car idle for half an hour at a time. Sorry to be so blunt, but I wouldn't do that to my car on a bet. I'm sure there are lots of opinions, and that's only mine. The only precaution I've taken - maybe it's stupid - is that I left it unlocked. My reasoning was that the security system wouldn't be a factor in draining the battery.

bruce, did u try to work out some deal with those parking guys? they may be able to do something

I would LOVE to here an argument as to why idling your car for 20 - 30 minutes could, in any way, would be harmful to it. As for disabling the security, simply install a cutoff switch and your car would be safer than leaving it open. BTW: What is the address where you park your car?

Don't even think about it. There's, like, two security guys with flashlights and walkie-talkies you'd have to deal with. And if you DID break in and steal my super cool Porsche umbrella, I'd hunt you down like a dog.

Thats the same thing I do it is single to - in Chicago right now but I am warm in Australia. My wife says she will not go out to the shop to start it till it gets into the 20's. So I will let you know how it does. It has been sitting for 2 weeks now. With the Charge O Mat II on it.

I think leaving it unlocked is the best. If the battery craps out it's very difficult to get into it, and open the hood/trunk.

I seem to recall that the manual says that if the car is parked for more than a few days, the remote entry system shuts itself off and that you will need to use the key to enter the car. I have an '02, so that may have been a new feature that year. I assume that they do this to save the battery. However, it does seem to me that a relatively new properly charged battery should be able to sit for several weeks, even in the cold, and be able to start the car. Secondly, I also agree that starting the car and letting it idle for 20 minutes is a bad idea. Modern cars are designed to be started and then almost immediately driven. Letting it "warm up" like this could overheat the catalytic converter. But even more importantly, at idle, the car barely generates enough electricity to run the engine, it's not doing much of anything to charge the battery. Now here's an idea - a battery trickly charger. Parked too far from the available outlets? Modern technology has invented a device that you should be able to use. It's called an extension cord. For you unlucky bastards living in urban environments in the frozen North, I think I'd just make sure that I have a very good, relatively new battery. If the car is going to sit for several months, then it should be winterized and the battery removed anyway. And those are my opinions. Michael

At idle, a properly operating alternator generates maximum voltage to the battery. The alternator does not generate higher voltage output based on speed and driving the car will not charge the battery any faster. I also believe, as you do, that all these cars go into a sleep mode after an extended period of time which reduces the draw on the battery. You should be able to get several weeks out of the battery with the car just sitting, locked.

If only life were so simple. My battery is dead as of last night. The battery was new last August. The car was parked unlocked for only about four weeks (though, yes, I also have that battery saver feature). And an extension cord is a fine idea if the outlet you're reaching belongs to you. Otherwise, it's theft, not to mention a breach of one or two condominium rules. So, unfortunately, not much I can use here. This, cats and kitties, seems to be a Porsche thing. I've stored other cars for months at a time and started them right up in the spring without any trouble. I guess for next year, I'm going to have to look at this cutoff switch thing.

Yup, they do. But I figured that if I could safely leave it unlocked (I can), I could get MORE than several weeks out of it. Why drain the battery with the motion sensor etc. if you don't have to?

OK - three more ideas. 1) Maybe the car goes into sleep mode when locked, but not when unlocked? So, maybe by leaving it unlocked you sped up the demise of the battery? 2) Maybe you had a bad battery. 3) Buy one of those portable jump start thingies. You can keep it in your condo, charge it up the day before you might drive the porsche, and then take it down there with you, hook it up (surely the battery will be alive enough to unlock the boot) and start the car. Cheaper and easier than the cutoff switch thing. I say this because I think it's quite the PITA to open the hood with no battery. There's a thread on that somewhere, I'm sure. I also got a little confused because I thought you wrote that "sometimes I can't park near the outlets" which led me to believe that if you did park close to an outlet, you would be able to use it. If it "belongs" to someone else, could you not just ask their permission to use it for a trickle charger? I mean, we're talking pennies of electricity use here. Buy them a nice bottle of wine. Of course, your life would be much simpler if you would just move South. Or West, as someone suggested. Michael

Moving south is sounding pretty good right now... On your first question, dunno. Interesting theory. Maybe next time I'll just let it sit locked and armed and see if that works better. On the bad battery thing, the service history on this car shows that it's had seven of them since it was new. I'm thinking the problem is a short somewhere in the car. I doubt it's worth even looking for at this point, and my mechanic tells me 996s are famous for them. Judging by the two page spreads of battery maintenance products in the last accessory catalogue I got, he might be right. The cutoff switch seems easier. On the jumpstart thingie, I got one last night. Hopefully, it does the job! Sorry for the confusion on the parking thing. Works like this: I live in a condo. The parking spots are deeded, so the car is always in the same place. The condo police won't even let you leave a snowbrush in your parking spot, so my guess is that pirating electricity with a 50 foot extension cord would be a problem. Condo life has its pluses and minuses... Really appreciate the suggestions, though! Great community on this board. Bruce.

hmmm... Why does my porsche manual state that you should never let it warm up by idling? and before you say "idling and warming up your car are two different things, I'm not talking about warming up the car" most people are not going to drive the car and warm it up and then let it idle for 20-30 min.

Watch out Aaron! Mr. Meanie will jump all over you if you even dare to suggest that he was wrong! Because he's never wrong. Seriously, he's not. Just ask him. And then ask him what oil viscocity is approved, er, recommended. Heh, heh. Michael

Rob, can you tell me a little bit more about this Charge O Mat II? I've never heard of it. Thx.

Get a $12 Walmart floating trickle charger, doesn't charge all the time just when the charge begins to drop, the charger turns itself on and tops off the battery and then shuts itself off again. Same as this overpriced charge o mat thing. I've been using this on my car, this being year 4, in Buffalo below zero at weeks at a time and have had no battery problems.

I got mine from ebay at a decent price. It plugs into your cigarette lighter socket and is the latest generation of Porsche trickle charger. It has mode settings for different battery sizes (e.g. motorcycle, cars), detects battery charge level and automatically adjusts its output for battery charge or battery maintenance. It has an overheat protection feature to cope with high ambient temparatures and is maintenance free. Made in Sweden. Part no. 955 044 900 56

Thanks Rob; it looks mighty cool. Love the LED readouts.