henkinc

I would think a low battery would manifest itself first in a slow/non start. Mine has never had a problem (in the two months I have owned it). It is a 2010 S
However, after staying off for a few days, there is a correlation with the sound system behavior. First it won't work for long with the motor off, due to car concern with battery drawdown. I get this, but it is REALLY insistent on not using the radio for more than 5-10 (or even less) minutes. This insistence is less extreme when it has been driven recently. In addition it does not recognize the USB stick (!) when it is in this condition.

So I charged the thing overnight after a short drive yesterday with a maintenance charger (1.5 amp) and it took less than 15 hours for the green light to go on, so maybe 15-20 amp hrs. Surely not a weak battery.

Anyone experienced any symptoms of low battery charge while having excellent starter motor turnover?
Charlie

JasonKM

Reality is that your stock battery is about 5yts old and these cars like to eay batteries and i would say the stock porsche batteries are not very good. Due to age i would simply replace with a new one. Lots of options out there as its a 94R or H7. Only 3 battery manufacturers that make all the private label batteries. One well priced option is wal-mart H7 / 94R battery, which is made by Johnson Controls. Also Costco has a battery for it (not sure but think it's made by Exide).

henkinc

agree battery likely on near last legs due to age. Thanks for the size info.

But on the other hand, it starts like a champ, and it gave a green light on the trickle charger after about 15 amp hours, which implies it is ok.
Charlie

JasonKM

But is it worth the risk if it fails when you're the road or out for a nice dinner?

Fahrer

When my battery was on its last legs, a PASM error would temporarily light up when starting the car. Not long after the car would turn over slowly on startup.

jhbrennan

OEM battery is infamous for start today, no start tomorrow with no leading indicators of failure - it's time to replace - why wouldn't you - it's probably the least expensive repair you'll ever have.

henkinc

First, let me say again I have this car only a short time, The CARFAX shows an battery/charging system check 2 months after sold at auction in late 2014, which I take to be either an "ok" or more likely it started poorly after sitting for two months.
So there is a Porsche 997 OEM battery syndrome? But then again, how about aftermarket suppliers? I replaced the battery in my 993 two years ago from Advance Auto and it never worked as well as the previous battery had when newish, leading me to be concerned about all modern battery suppliers (or a late-emerging small electric fault- who knows?). But at least that 993 battery progressively lost power, as measured by voltmeter (going under 12 V over a week or so) and by starter action. I will check with the dealers to see if this is a 997 battery syndrome in their experience. The other mechanics I know are leery of current battery suppliers.

In meantime, this current 997 battery shows 12.3+ V overnight, 12.47 immediately after a short drive, and the USB problem seems to occur without correlation to anything except maybe locking the car. And then it fixes itself later on, as if the car has to "reset." In short only symptoms - if anything unusual at all- is some minor, self-correcting sound system electronics issue, and all other indicators are fine.

Finally, I will check to make sure the battery in the car is dated to original or indeed may have been replaced recently.

Thanks.

Have other thread readers heard of this OEM battery syndrome?
Charlie

Wayne Smith

There are lots of computers and battery drains in a modern car. Sitting, the battery drains. A drained battery creates sediment from non reversible chemical reactions. A drained battery can be a bad battery. A good battery will read 13 to 14 volts when sitting. Yours is low. Getting past everything else, when you buy a 911 budget a new battery at the same time. That is simple insurance. A low battery will cause all kinds of havoc with the management systems and create a variety pack of so called failures. Save yourself a lot of trouble ... Get a battery!

PelicanParts.com

Sooner or later, everyone will have problems starting their 911. The first place to look for trouble in your starting system is your battery. The battery is perhaps the most important electrical component on the car, and due to its design and nature, it is perhaps one of the most troublesome. Can read up on how to troubleshoot it here.

-Luccia

CAVU

Bounce your voltage readings off this http://www.batterystuff.com/blog/how...ry-is-bad.html I am suspicious of your battery. Pull your battery and drop it off at your favorite autozone or advance auto parts and let them run it on their tester. I think they can even do it with the battery installed if you prefer...no my preference though.

"OEM battery syndrome". Nope, never heard of it. It sounds like a "blame all Porsche battery failures on their battery OEM because my battery failed at x years", instead of trying to understand the multiple other factors that are in play with a big one of "not driven enough".

jhbrennan

"OEM battery syndrome" exists because many of the cars are driven infrequently, hence the reason Porsche doesn't warranty the battery if the car is driven less than 6,000 miles/year. Aftermarket batteries work fine - lots of praise for Wal-Mart version and Interstate but there are others. If your battery is an OEM Moll its "birthday" is stamped on top of the negative terminal - IIRC the format is MMYY or maybe WWYY.

henkinc

I finally got off my butt and looked closely at the battery. It is a new looking "Super Start" 900 CCAmp device, the 49EXT model, listing at O'Reilly Auto Parts for $145 online. Its appearance correlates with the Dec 2014 battery charging system checkout on CARFAX although it has no date markings on the device or on the plastic calendar-like space under the title on the negative side. A review web site says Super Start batteries are manufactured by East Penn Manufacturing. East Penn is well know for their Dependable Deka battery brand.
One can check the acid level taking off the screw caps even though it is a non-maintenance design. Level and acid color look fine; plates are more than covered.
Now, its life in salesrooms without a trickle charger might not have done it any good. So I will measure the Voltage when my trickle charger says it is "green" and go from there. At any rate, clearly not OEM, and quite apparently not old.
Comments? Is Deka (or Super Start) a good brand in fact?
Charlie

CAVU

Charlie, The battery may have had a hard life through no fault of your own. At this juncture, I'd say it's worth a trip to Autozone or Advance and let them connect up their tester and give you data for your decision. If you decide to get a new battery, there are a number of great threads on batteries. Trickle chargers are not ideal. It's worth the investment for a decent multistep charger. Deka, and the other 2 all make decent batteries to different specs and designs. Lots of folks have lots of opinions about which brand and lots of large volume discounters (Walmart) and auto supplies stores with coupons.

ADias

That is perfectly normal - ancillaries auto cut-off - and has nothing to do with battery charge. Use a voltmeter to measure battery condition with (13-14V) and without (12.2-12.4V) the motor running. Battery life depends on use, operating temperature and other factors. I have seen batteries lasting 2 years and batteries lasting 7 years.

A 997.2 sitting consumes about 1Ah/day.

henkinc

I was using the trickle charger but I do have a real battery charger of a certain age I can try as well - or buy a new one. But for those months when I will leave the car unused for a couple of weeks at a time I thought it would be better to set up the trickle charger, and indeed it turned "green" over one night when tested this week so I was pleased with that result. I will measure the voltage upon disconnecting it with another test, and I expect it will read 12.7 V just after disconnect.

I will try the engine on/off test and little doubt it will reproduce around 12.3 V off and well over 13 V on, since everything works fine as I drive the car - and when I start it for that matter. Can't hurt to have Advance Auto bring out their little tester with car and AC running also.

Only 1AHR per day is a great data point. That seems quite modest given my experience (2000 Audi A6 TT, 1991 M5) with dead batteries after 3 weeks out of town on past German cars and my purchase dealer advice to limit this practice to about two weeks without a charger.