low battery indicator light stays on

[ecuke]

After a long winter, I needed to charge my dead battery which was replaced 2 years ago. The battery charged in full in 5 hours. Drove for a few miles; went out the next day for a few miles, and then the light came on. Then shut the car off for 20 minutes and engine would not turn over. Then 1 hour later engine turned over but was weak. I have read some threads that this may be a regulator/alternator. Would another charge do the trick???

[JFP in PA]

Probably not. If your regulator is bad, you can tell by testing the battery voltage with and without the car running with a simple volt meter; or if you have access to a load tester, perform and engine running load test, which should cause the regulator to respond with about 15.5V or so if it is OK..........

[mptoledo]

Yep, get a $10 meter from walmart. located in their automotive department. I used their batter charger/tester all in one. Test your battery with car turned off, then with car on. You should jump from 12 v to 14 v, if it doesn't go up at all its probably your alternator. Thats what Mine did. I got my alt from Orielleys auto. $220 with lifetime warranty. I have a DIY for alt replacement in the DIY section.

[ecuke]

So JFP says to test for faulty regulator? Is this also part of the alternator? I have a voltage meter but now have to recharge the battery in order to get correct readings. I understand the voltage increase while engine running (test of the altenator); not sure about the voltage regulator .

[sd_boxster]

Allowing a "normal" car battery to discharge completely and remain discharged for a significant period of time causes sulfation - a chemical deposit on the plates of the battery - that reduces the capacity or renders it completely useless.

One or two seasons - especially if you have some parasitic drain - is enough to destroy a new battery.

That said, you might have a charging system fault - but if you haul the battery to Autozone and have it tested, I bet they'll tell you the battery is shot. Order a maintainer now, while you're thinking about it, so the battery can be properly conditioned the next time you store it.

[ecuke]

Thats interesting; Would it be OK to charge the battery back to 100% and then do my voltage tests, since yesterday I did have it charged 100%(according to the battery charger) just to be sure my alternator is working>
. Although some other forums suggest the alternator replacement is rare on this car (35k miles 2001)

[mikefocke]

You abused the battery so it probably died. If that was all that happened, it is an easy fix and no need for a special Porsche battery, any of the correct size will do. And if you get the battery into any place that sells batteries, they will run a test for you in a twinkle that confirms they need to sell you a new battery. You can take the battery out and install the new one yourself without any risk of stalling and not having juice to start by just removing two access screws, lifting the cover and climbing in the front trunk and removing the battery....with the key out of the car and the radio code in your pocket if the radio needs one.

It is out-of-hibernation season, batteries are failing left and right.

A list of batteries that are known to work at here

[jmatta]

Next time buy a battery maintainer...you can not leave a battery to completely discharge and expect miracles to happen. A $25 or $30 investment will cure your future problems; that is, after you purchase a new battery.

[sd_boxster]

A somewhat more expensive alternative to a battery maintainer - but no less effective - would be to consider moving somewhere where "Winter" means "65, partly cloudy, and a chance of showers" rather than "start tearing up and burning your hardwood floor - the heating oil delivery guy slid off a bridge in an ice storm."

[ecuke]

Man SD am I ready for that move!!! We had such a tough winter; powerless for 5 days with tree damage everywhere. So Cali sounds good, but cant afford it. Mabye Florida in a house boat with a Boxster engine

[ARModen]

If you get the light when the car is running then it is likely a regulator/alternator issue. I've never tested to see if a really bad battery issue can cause this on a newer car. I know an older Porsche won't get the light with it's battery removed or completely shot. I've got firsthand knowledge of both of those.

A battery is a chemical/mechanical device. Fully charged it's basically lead plates and sulfuric acid. As the battery discharges the lead dissolves into the acid. This is normal and completely ok. If the battery is left discharged over a long period of time then the lead will collect at the bottom. The more lead on the bottom the less charge the battery can hold. At some point the lead on the bottom will short the plates out and then the battery is toast. The reaction is temperature sensitive so very hot or cold weather will change it's behavior.

My guess is the regulator/alternator is failing. The battery was probably discharging to keep the car running the first and second days. Once the battery got too low the load on the alternator caused the warning light to come on. Have the alternator and the battery checked at a parts place would be my recommendation.

[ecuke]

OK had the battery tested at Interstate dealer and battery is fine; therefore I need an altenator. Question is: do I need one with or without free wheel lock? 2001 S 6 speed