Traud

Very nice advice Gents. I purchased an Amp Meter and performed the test. The draw noted was 15 milliamps (0.015). Now suspecting the battery, however, I did not perform the test as prescribed by whalebird. That will be my next test. If the Optima is indeed bad, what is the consenses on a satisfactory replacement battery? What does Porsche recommend? (What type battery was furnished when the car was new?)

theiceman

wow what a guess !!! 15ma is fine so oyur batery is toast I think . This thread could go on forever if we go through the battery ebate again. I just threw in an interstate for 90.00 but there are guys who swear by the optima , it won't leak in your car ( mine doesn't anyway ) it is light and will make your wallet light too from what I hear. Just make sure you have 13.5 volts or so with the engine running.

Traud

Thanks Ice. I'll check the charging system - that should quantify the problem and put this issue to bed.

Mike
82 911SC

JBrown

You have no draw, good. That is why I recommended checking the charging system first. Like iceman said start the car, put the multi meter on volts and make sure you have between 13.5-13.9. The higher the beter. You can drop as low as 13.2 but that is a weak alternator. The only reason to use an optima is when you play radio without car running. It holds good storage current. If you just want a quaility battery. Go to your mechanic and see what he uses and make sure it comes with good exchange warantee. There are alot of good batteries out there.

Brads911sc

There are only two wet cell battery manufactures in the USA (insert -- that make batteries for retail outlets like sears or your local garage).. Exide and Johnson Controls. For years, Johnson Controls make Diehards as well Interstate. That changed in 1995 when Sears switched to Exide. Interstate is still made by Johnston. In the end, all wet cell batterys are made by these two companies. The Diehard seems to have dropped alittle in quality after the switch to exide. So like JBrown says, in spite of all the hype, get the one with the best warranty, exchange program, and CCA's you can for what you want to spend.

theiceman

My nighbour has a 944 , he doesn'tr drive it that often but he seams to be eating diehards. I think they really need to rename that thing. My interstate is rock solid.

Brads911sc

Agree Ice. Lots of stories on the Diehard's demise after they switched to Exide. My Interstate is 5 years old and is rock solid as well...

whalebird

I thought Douglas batteries was one of the few manufacturers of batteries. For years Douglas was the only factory replacement recommended by Porsche, other than their own batteries.

Brads911sc

Whalebird, you are probably right. I should have said the only two mainstream battery companies that sell to retail outlets like sears or your local parts store... There are several that probably make batteries for car manufacturers. The Diehards, Autozones, Interstate, NTW, Walmart, etc of the world... are all made by Exide or Johnston. If you check out Douglas, you will see that they dont specialize in auto batteries, mostly industrial stuff... although they do make a Guardian Line that could be sold to porsche or other car companies... They dont sell many sizes of even that line... only 5 batteries come with the universal post.

whalebird

I know that there are only a few, and that there may be little differance between most car batteries. I have ordered batteries from the Porsche dealer and I would get a Douglas. with no electrolite in it. then I had to add the acid. That stopped a few years ago and I was just directed to Interstate. I really had a time getting the two small batteries for my "73 911S and wound up ordering them from one of the "batteries Plus" type of places who at the time said they could get them from their warehouse. That didn't happen, but when the batteries did arrive, they were douglas that I had to add the acid to.
Seems like there is a lot of conjecture about batteries, but starting/charging/batteries are very easy to diagnose. And, auto batteries have an alarmingly high failure rate including the optima.

Brads911sc

Agree. I worked for Sears Auto as a tire and battery sales manager when they switched to Exide and there was alot of hype. Patented this and patented that... Mostly BS if you ask me. In the end... we would return 10% on any given day and it seems to me (hypothetical only) that the diehard and interstate lasted about the same amount of time.. which made sense since they were both made by the same company... I mean has the technology really changed that much in the last 20 years? I'd say not... I prefer to just stick in my gp 48 or gp 49 Interstate Battery and spend my money on other things...

whalebird

I hope not to further OT this thread, but I did lots of battery replacements while serving as a Mercedes roadside tech. Of corse I used the factory MB batteries, but interstate was making a Mercedes replacement that was really nice. It was not the typical gp48 that they sold to most benz owners, but packaged as a mercedes battery with like-factory handles and color/lettering. One had to ask for it specifically. It was heavier and seemed like a better fit. I have found that the factorys will dictate build quality to a supplier and use thes parts for factory supply. For instance, I strictly used factory belts on Porsche cars. A 911 fan belt would have Danco, or Goodyear pronted on it along with PORSCHE, but if one went to the average autoparts store and got a Goodyear or Danco belt it was not the same at all. In this case, the factory was a much nicer unit and when a customer just dropped a cool grand on a 993 major service, it looked nice when they opened the deck and saw PORSCHE written on the parts. Certain thing are well worth the price paid at the dealer, and also, one must be very aware of what they are getting from parts houses like Pelican/etc. There is a differance. Just with batteries.....I'm not sure.

Traud

Gents - Testing complete. The alternator is putting out 13.9 - 14.0 volts, which I believe is satisfactory. The amp draw is nill (-0.01) is I indicated previously. So, it appears the battery is problamatic. I found out the previous owner did not drive the car at all (or very little) the 8 months prior to my acquisition. That Optima battery was installed at the beginning of that 8 month period. Not driving the car plus my once a week drives possibly has contributed to insufficient charging/cycling of the battery. I have a battery charger unit with deep cycle capability on the Optima at the moment. If that does not work, then a replacement is in order. BTW, the Optima is a Blue Top. Are the Yellow and Red superior? If I were to go the Porsche dealer, what would they likely sell me as a replacement battery?

Nice commentary on battery options....

Mike Traud; 82 911SC

whalebird

I was told by Interstate (I am an interstate dealer) that the yellow top optima is junk. They have warranteed many of the ones they have sold. They say the red top is the only one they reccomend. Aside of the optima A common battery failure is an internal short. This is when the battery will make ample amperage at times, but fail after a good load is applied. This type of short will not allow proper recharging currant into the battery from the alt. Will not carry enough amps to cold start the car, but will do just enough to avoid diagnosis. It will make good voltage when testing with a meter, or even accept a charge part of the time. In this failure mode the battery is sensitive to temperature and load. A good field tst of a battery is taking a volt test with your meter. Remeber that a 12 volt battery will make 12 volts when it is completely discharged. At about 12.5 volts it is 50% charged, and at 12.8 volts is 100%. If you put your meter on it and it reads less than 12 volts without a load, it is pretty much dead and not coming back. If you put your meter on it and load it with lights, blower, and especially rear window defroster and of corse cranking-you should not see anything less than ~10.5 - 11.5 volts. If it reaches below 9 volts - replace it. Optima batteries may behave a little different, I don't know.
As far as your replacement, I don't know why a optima red-top would be a problem short of price. As mentioned above most of the wet-cell batteries are made by the same people. I shop for a battery by warranty-the longer for free replacement. Most batteries are warranted in a pro rated fasion. Free replacement for the first two years, then prorated for two more. Some are offering free replacement for longer periods, say three years. Given the high failure rate, I like a battery with a long free replacement warranty. I also like to get the battery from somewhere I can easily replace it, like Walmart, which are everywhere. Wherever it may fail, you can run in and trade it without the hassel of some kid trying to load test it and verify its failure. Easy come-easy go.
Hope this helps.
Good luck

Brads911sc

The Porsche dealer battery is an Interstate or at least they sell them. If you look at Interstate's website, you will find your local porsche dealer is also an authorized Interstate dealer. Its what I would go with. The Gp 91 will run you $125.