Another battery issue

I just bought a new duralast battery from Autozone. If my car sits for 3 or 4 days, it will not start without a jump. Once it's started, its fine for a few days. I thought it may have been the cold weather, but it hasn't been cold... Could this be the alternator? Thanks people!!

Most likely (if the battery is not faulty) you have an errant current draw. Do you own an ampmeter or a multimeter? If so, you could put the multimeter between the battery negative post and the chassis ground and then disconnect the ground strap from the battery. The multimeter will then show the number of (hopefully) milliamps of current draw. If the number is high (~100mA?) you would need to start checking door switches and then start pulling fuses individually until you notice a large drop in current draw. Pulling fuses (with the multimeter attached) and relays (to check a relay you need to attach the multimeter before you remove the ground strap from the battery) will point out the offending component or wiring. And then you just need to go from there. If the current draw is not very high then you check the atlernator and voltage regulator, etc.

you also need to lock the car and wait for it to go to sleep before you start pulling fuses. do you have aaftermarekt stero equipmnet or sat radio or a radar detector or a phone charger you leave plugged in all the time

Radar is left on. Guess I'll have to unplug it.

that could do it. easy way to do it would be to run the trigger to 15 power instead of 30 power that way its only on with the key on and you dont have to plug or unplug or play with switches

Silly question, but does leaving a window open affect the drain? Bill

NO SIR

It's pretty annoying the key-off drain is so high on these cars. The key remote is among the poorest performance imaginable, yet they turn off the receiver after a week to preserve the battery. My minivan sits for two weeks w/o turning off the receiver (which works from 10x as far away) and the battery doesn't go dead. I love Porsches, but really. Pfft! Bill

actualy the remote shuts off for security reasons

The owners manual states it's to prevent discharging the battery. Bill

How do you run the trigger to 15? Whats the trigger, whats that mean?

if you have a wiring diagram for the radar it will shwo which is the trigger wire . 15 is a key on power that turns off with the key off. there should be 2 term 15 points in your fuse block

I don't get it, sorry...

From what was said, I suspect it's just a plug in RADAR - correct? So unplugging it is a great idea, will reduce you power drain for sure. Amazed that your battery could be killed by this alone - do you perhaps do short trips when you do use the car, not giving the alternator enough time to recharge the battery after the start? if this is the case - get a battery maintainer from the dealership, and plug-in at the lighter socket. $60 Assume you've checked the obvious - such as interior lights being left on, or the trunk or rear deck-lid being left open with light on? One other possibility that comes to mind is a failed ignition switch. These can fail leaving the car 'powered' even with the key removed, and drain the battery that way very quickly. On your 02 it's a possibility - and in fact would explain the rapid drain better than a radar detector being left on. Current draw when idle should determine if you have excessive standing current - as previously mentioned. Brad - is there a quick test to see if the ignition has failed 'powered-up'? If that's inconclusive you could have a faulty battery - or faulty charging.

oh YES...... you're letting the power escape at night... gotta be careful, they take off and never returns...... happens to me all the time....

Well, it if makes the alarm think a switch isn't closed, who knows what it might do. Bill BTW, I'm a EE.

i dont understand what your asking ?

If the ignition switch fails - and I understand this can leave circuits that are normally powered off live - is there a quick check on the dash or something that would confirm that the ignition switch had not killed all the circuits it's supposed to? i.e. something obvious that should not work without the ignition being ON, but is still working with the key removed.

When mine was failing sometimes the PCM would stay on after I took the key out.

Don't know if you covered this but leaving your key in the ignition will drain the battery over a period of days. (Even in the ignition off position)

the headlights are the most obvious to stay on with the key off but generaly you can feel a bad switch if hes leaving his radar plugged in thats the most likley casue you would be amazed how much current those little things will pull

FWIW, after letting the car sit for a few hours and everything power off and settle down, my battery drain is about 18 mA. Bill

Is the dash lit up while its 18ma ? do you have all the lacthes closed and the alarm armed ?

That was with everything off, key out, not locked or alarmed. Trunk open for a few hours, long enough the light in there had timed out.

proper draw test is all lacthes closed alarm on everything else off

"proper draw test"? Please. That's not how I "store" my car in the garage. I'll redo the test though, just for the hell of it. Bill

proper draw test per porsche, you can do what ever the hell you like