Silver Surfer

I have owned my 993 since 2012, and my third battery is about to give up the ghost. I replaced my alternator last year, and I keep the battery on a charger when I am not driving the car. I do not plug in any devices, I seldom even use the radio when driving, and my dome lights are always switched off. The last two batteries have been Porsche branded.

Do any of you have any theories why this might be happening to my car?

vincer77

What type of charger are you using?

Silver Surfer

I don't know. It is a trickler I bought at an autoparts store.

PelicanParts.com

Typically batteries come with warranties. Might be something where you take it back to the place you purchased it and see what type of warranty they offer and if this is something they see often with the type of battery. It's a place to start at least.

-Luccia

Silver Surfer

Porsche has a one year warranty, and I am within it. But I should not be burning through a battery every year!

mpruden

Perhaps you're using the wrong tool for the job?

Shouldn't you be using a battery maintainer instead of a trickle charger?

I could see a trickle charger overcharging the battery causing damage.

Silver Surfer

My bad. It is a battery maintainer, not a trickle charger.

Neil Perry

I would check the negative power cable from the battery to the body, these tend to go high resistants, hence low battery charge and lower start voltage and current. I replaced mine about 6 months ago, it was 7.8 ohms resistance. The car started so much better, once replaced. The new genuine lead is only $25.00

Worth a look.......................

vincer77

If it is a cheap charger you could be overcharging. I have a CTEK and have had great luck. What is the symptom when batteries die¿

993/907

Something is definitely wrong.
13 years on the first battery in my '95, still on the 2nd battery..........

Porsche70T

I just had the same problem in my Acura. I replaced the battery twice under warrantee. Charging system kept checking out okay and finally traced the problem to the negative battery cable like mentioned above. It's been 2 weeks and so far no problem.

Aaron 993C2

+993

pp000830

A battery emits moisture as the electrolyte evaporates. When on a trickle charger a low level of electrolysis is going on continuously so it is incrementally loosing H2O over an extended period. For example I opened the cell covers on my battery and they were down on fluid over two ounces in each cell. As the electrolyte volume is reduced the ability of the battery to accept a charge and have reserve starting capacity is diminished. All batteries I have seen have a ring so as you fill it the ring changes the look of the surface of the electrolyte in each cell when the fluid touches the ring indicating the cell is full up. One should use distilled water to top off the cells. Even conventional maintenance-free batteries usually can have the covers pried off and filled. Maintenance-free = don't maintain the battery , just buy a new one every two or three years when it dries out. If you look in the battery cells and see the plates above the level of the water your battery is seriously low on fluid. Batteries eventually do wear out via precipitate crystals forming in the electrolyte and shorting out the plates diminishing the number of plates and so reducing the voltage. Also deep discharging a conventional batter causes the electrolytic process to coat the plates reducing their efficiency so after three deep discharges many batteries will fail to fully recharge and will need to be reconditioned. Modern car batteries are very carefully designed to have a limited service life as with some very simple cost-free design changes a car battery could last a decade or more but then the battery manufacturing industry would be decimated.

Andy

Raleigh993

Good info!

I am fortunate that I have encountered very few electrical problems to date and able to drive it often enough to avoid a battery maintainer.

pp000830

FYI - The battery is always loosing H2O even during alternator powered charging so the electrolyte fluid level should be checked and topped off once a year in most cases.

Andy