CJ Dillon

The original Porsche battery on my '95 993 -- which is a weekend driver -- seems to be weakening.

It has deteriorated from being able to sit (with the factory alarm on) for 3 weeks three years ago, to two weeks last year, to one week now.

Here's my question: From searching the forums I understand that draining the battery can damage it's ability to hold a charge. I've had to jump-start the car about 6 times in 3 years -- what are the odds that the battery is damaged and needs to be replaced?

While I'm at it, here are a couple more questions:
> How much city driving does it take to fully charge the battery? (And am I compounding the problem by only driving the car for an hour after I jump start it?)
> My car is parked in an apartment complex without easy access to AC power. Am I further ahead using a trickle charger than a battery maintainer?

Thanks in advance!

nile13

Replace your battery. They don't last that long, period. Yours is dead.
I just had mine replaced two days ago. Same issues with sitting and not starting. Mine was exactly 6 years old. Generally, batteries last 4-5 years on average in my experience.

CJ Dillon

Thanks Nile.

That's the conclusion I had reached, but it always pays to check with the experts!

Ray Calvo

Replace your battery, cheapskate - it's way overdue!

I don't think I've had an OE Bosch battery in any Porsche last more than 3 years.

The alternator/regulator in the 993 is a good one; I have found it ('95 993) putting out close to 14V right after starting the car (with the battery in a good state of charge). With a dead battery, drive it around for an hour after getting the car started. After that, I would say drive it for at least 15 minutes to recharge the power you drain from starting the car every time you drive. 5 minute trips are horrible for the battery - as well as the engine (you never get all that oil heated up).

If you are parking it, a battery maintainer is much better than a trickle charger. A trickle charger will boil the battery low or dry if you leave it connected for several days (the charge is not regulated). A maintainer is a trickle charger with a voltage regulator built in. I't s far betterthan a simple charger.

John W

heh heh heh, I haven' been on list for a while, and what do a see on my return ?
A post from Ray Calvo !!
Only thing missing was the now famous RTFM

I agree, change the battery.
I put my car on charge one week a month through the winter, and it keeps it in pretty good shape.

Be aware that some battery maintainers attempot to condition the battery. They do this by placing a small load across it and monitoring the voltage drop. Some then fail to recharge the battery properly. I have this problem with all of the generations of the Optimate chargers I use on my bikes,
which is why I don't leave the charger on all the time.

Cheers,
John.

SLVR

Older batteries (anything over 30 months) are usually pushed over the edge by being drawn down too far. I had an original battery in my 2000 ML430 which was going very strong (it is a HUGE 100 Ah monster!). Though I had noticed it becomiung less eager on cold days it was still serviceable. It got killed when my son left the Rt. RR door ajar one nihgt in the garage and I caught it only 48 hrs later.

On garage queens with nasty long cable front to back I would expect 30 months to be the max on most batteries. You might get 48 mths with luck, a lot of it, and neither extreme heat not cold conditions.

Crappy batteries in my Jeep GC V8 required changing every 16 mths until I upgraded.

mjsporsche

Agree that it is time to replace the battery. Many people recommend the Interstate brand batteries as longer lasting.

Ray Calvo

Interstate and Sears batteries are both good brands in my experience. Don't know about the present Optima in the car now (less than 1 year old) but know it recovered from a total (to zero volts) discharge without any apparent damage. Time will tell.

Bill (NC)

We bought a Corvette in 75' and needed a battery about three years later. Firestone was running their "forever" battery at that time, so we bought one. I felt like that old guy in the commercial because ever 3 or 4 years I would show up at the Firestone store for a new battery. They blamed the quick demise of the batteries on the fact it sat so much over the winters, without any maintance. Needless to say, when we sold it after 27 years the Firestone guys were appreciative. I have an Interstate now in the 993 and use a Porsche battery maintainer, so I hope that improves the battery life.

Ron

I've had an Optima in my car for about 2 1/2 years and it's been discharge enough four or five times to such an extent that it would not start the car. It has charged back up each time and thereafter it works fine for awhile. Then it has trouble staying charged to say 12.6 volts. I did start using a trickle charger that puts out .5 amp. According to the Optima website it is ok to leave a trickle charger connected for an indefinite period of time.

I would be the first to admit that my problems may be related to the fact that my car is not driven that regularly, but I would think the trickle charger would help the situation.

When I complained to customer service at Optima I found them very helpful. After having no success getting the vendor I purchased the battery from to warranty it the customer service person said they are sending me a brand new one. I will probably sell it because I think, maybe mistakenly, that I should not have such problems with the Optima since I keep it on a trickle charger per the instructions on the Optima website. Maybe the Optima is more sensitive to getting discharged if vehicle is not driven.

I've ordered the Odyssey PT1200 from West Coast Batteries as a few others have. Maybe it will stay charged better.

nile13

On a complete tangent. In the past 6 months I put two new batteries in my two cars. Both came with 84 months warranties. That just scares me. What are the chances of either car being with me in 7 years?

Randy M

What's the deal with Porsches and batteries? They are notoriously bad on batteries. I've had 3 911's. All of them have been hard on batteries. Whenever batteries and Porsches come up in conversation everyone's complaining...
And it's not always because the cars sit.

Randy M

Oh and by the way I bought a new optima red top, put it in, drove the car back and forth from work for 3 days (15-20 mile trip each way) parked it in the garage for 8-10 days, deader than a fricken doornail......

Battery is now disconnected...

Ron

Assuming the alternator is working properly what do you think causes this problem?

I've read about cars having a constant drain even with the alarm not activated. I'm not very good with electronics so I'm not sure where or how to hook up a gauge to see if there is a drain on the battery with the car just sitting in the garage. I do have a Fluke gauge that can measure up to a 10 amp draw but, again, I don't know how or where I hook it up to check.

1999Porsche911

What's the deal with Porsches and batteries? They are notoriously bad on batteries. I've had 3 911's. All of them have been hard on batteries. Whenever batteries and Porsches come up in conversation everyone's complaining...
And it's not always because the cars sit.


There is not a problems with PORSCHE and batteries. ANY car that sits for long periods of time will degrade the battery more than one that is driven regularly. The charging system of the Porsche is no differnet than any other car and puts no special pressure on the life of the battery.