Battery drain

[gnetwerker]

I'm not a super motorhead, but I thought it would be simple enough to install an AUX audio cable to the CDR-220 stereo in my 2001 S. Well, either by coincidence or because of something I FU'd, I am no longer keeping a charge on my battery. The car starts when jumped, it starts if I charge the battery overnight, but within a few hours being turned off and parked, the battery is drained. There are no obvious problems -- no lights left on, etc. I pulled the radio again to see if I had pinched some wires or did something else obvious, and didn't see anything. I'm not near a shop right now, so I haven't tested the battery, but it is only a year or so old.

The good news is that the radio now works with my MP3 player, but that's not of much use if I can't drive anywhere!

Ideas?

[Tool Pants]

Not the electrical guy. Think you have a new battery going out. Have it load tested. Don't see how an MP3 on aux-in could drain the battery, when the radio is not even on. Plus the radio drains so little amps your battery should not be dead the next day.

If you search around I bought an Autozone replacement battery some years ago. After some months it would not keep a charge. I could drive all day and in the morning is was dead. Battery was replaced under warranty.

It was another dud. When I got home from work I would hook up my 10amp charger for a few hours. Would not start in the morning. I have the stuff to test a battery and one of the cells was bad, which usually mearns there is a short inside the battery, and a fully charged battery reading 14 volts will quickly drain itself if it cannot hold a charge.

Back to Autozone to have it tested with a guy who pretended he could not speak English when I asked him a specific question. He tested for volts and it showed good. Amps are what you need to start a car. I asked him if he was testing the battery for the load with amps - that is when he said I needed to speak to the manager.

That is why a 12 volt flashlight battery will not start a car - the starter needs amps. I received another battery and this one has worked fine for about 2 years.

[wemkehou]

I have a similar problem on my 99 911 (996). I have had two bad batteries in the last 15 months. The current (dead?) battery is from the Porsche dealer (Bosch) and was only 8 months old....and the dealer will not offer any warranty. :angry:

Before I replace another battery (probably from Costco), I have a few additional symptoms:

1. My trip odometer and clock reset when I do my first attempt to start the car (with or without a battery booster pack connected). It usually will crank once and fail to start. Further immediate attempts to turn the ignition key result in a relay-clicking sound but not for more than a few seconds and definitely no engine crank. I usually see the voltmeter on the dash drop from 11.8 down to 11 volts once the short cranks fail to start the engine.

2. If I am lucky and wait about 30 seconds with the ignition turned off and a battery booster connected, I can usually get the car to start, albeit with a weak initial crank.

3. The voltmeter on the dash shows 14 volts once the engine starts and then usually drops down to 13 volts after 15 minutes of driving. Once I saw it drop when I turned on my headlights, but it may have just been coincidence with 15 minutes.

4. After even 45 minutes of highway driving, I am uable to immediately restart the car after turning the engine off.

5. The Porsche dealer did a current draw check when I got the last battery and found a slightly higher draw (100 ma vs 50 ma expected) but did not think it could cause problems. I also have an aftermarket iPod hookup.

6. I now have both a Porsche battery maintainer and a battery charger. The charger seems to show the battery is fully charged but I still need a battery booster pack to get the car started.

I was going to start a new post but I thought I might have the same problem.

Any feedback would be appreciated. I am really impressed by the discussions on renntech.org. :renntech:

Thanks!

[Hanziman]

I had a similar battery issue with 996 C4S which I kept in garage for half year every year - always draining the battery even if the battery was disconnected. Would not keep up voltage after recharge - usually resulting in a lame cell in the battery. Took me 3 brand new batteries - until someone tipped me that most new batteries need a refill of battery fluid (acidic water) after a month or so of being used first time. Well, this did the trick - no battery problems ever since.

[gnetwerker]

Yep, on analysis, even with a 6amp charger on it for 24 hours it isn't over 65% charged, so it is likely a bad battery. The coincidence is weird, though. I'll pop the tops and look at the fluid levels tomorrow and let y'all know. If that doesn't do it, its the shop next week and see what they say.

[mpdlg]

I have a similar problem on my 99 911 (996). I have had two bad batteries in the last 15 months. The current (dead?) battery is from the Porsche dealer (Bosch) and was only 8 months old....and the dealer will not offer any warranty. :angry:

Before I replace another battery (probably from Costco), I have a few additional symptoms:

1. My trip odometer and clock reset when I do my first attempt to start the car (with or without a battery booster pack connected). It usually will crank once and fail to start. Further immediate attempts to turn the ignition key result in a relay-clicking sound but not for more than a few seconds and definitely no engine crank. I usually see the voltmeter on the dash drop from 11.8 down to 11 volts once the short cranks fail to start the engine.

2. If I am lucky and wait about 30 seconds with the ignition turned off and a battery booster connected, I can usually get the car to start, albeit with a weak initial crank.

3. The voltmeter on the dash shows 14 volts once the engine starts and then usually drops down to 13 volts after 15 minutes of driving. Once I saw it drop when I turned on my headlights, but it may have just been coincidence with 15 minutes.

4. After even 45 minutes of highway driving, I am uable to immediately restart the car after turning the engine off.

5. The Porsche dealer did a current draw check when I got the last battery and found a slightly higher draw (100 ma vs 50 ma expected) but did not think it could cause problems. I also have an aftermarket iPod hookup.

6. I now have both a Porsche battery maintainer and a battery charger. The charger seems to show the battery is fully charged but I still need a battery booster pack to get the car started.

I was going to start a new post but I thought I might have the same problem.

Any feedback would be appreciated. I am really impressed by the discussions on renntech.org. :renntech:

Thanks!