can someone take a pic of the vin plate under the battery tray i cannot find mine and want to know where its located.. thanks!

 

Just for comparison sake, I had an Interstate in my '05 C2S that lasted 3 years, 7 months. The cranking got progressively slower, especially when the engine was warm until I recently got stranded out running errands.

I paid my independent $155 to swap out a new World Source One battery - direct replacement with 2 year warranty but I expect it to last a lot longer than that. My shop recommended this as a great replacement over the Porsche OEM battery. We'll see how it does but the swap out was flawless (no error codes), and the crank is back to normal!

 

I replaced mine with a Duracell (94R) from Sam's Club for $89. 3 year replacement warranty. Perfect fit. Vent tube adapter included.

Previous owner had an Interstate 91 in it (smaller). It never cranked as fast as it does now with the 94R

 

I purposely bought the larger size so I'd have more CCA. Seemed like the 'best bang for buck', and using the larger size only added a few minutes to the swap. I actually did the swap in the parking lot, easy peazy

 

I found the information on this form very useful and reassuring recently so I’m sharing my story, it might help someone.

Battery Failure or Electrical Fault?: I have a 997 Carrera S (on the road Sep 2006). I have driven only 25,000kms from new. It has been parked outside in a car port, I live in Belgium, weather in the winter doesn’t drop below -5C typically. A few days ago I parked the 997 at the airport and went on an overnight business trip. When I returned and tried to start the car I saw several warning lights come up on the dash such as Airbag Failure and PSM Failure, plus more, the engine didn’t turn. I tried a few times and the dash behaved very oddly, even the radio and aircon displays flashed on and off at one point. It wasn’t at all clear that it was a battery problem, it looked to me like a scary electronics fault, uggg. Luckily an airport car park attendant offered assistance in the way of a jump starter gizmo (guess I’m not their first non-starter) which we attached to battery terminals. Battery is under the hood under a large black plastic panel that says Porsche on it, easy to remove. He snickered a lot, guess he usually gets to start old Fiats so this may have been his first Porsche. With the jump starter gizmo attached negative first and then positive terminal, the engine started instantly after I turned the key and the dashboard immediately returned to normal. I drove home a bit nervous worried that if it was an electronics problem it could fail at any time not to mention the hassle and cost of a repair.

5 year battery life is normal: At home I googled my problem and found this forum which suggested that 5 years is a reasonable life for a 997 battery also that several 997 owners have done a DIY replacements successfully. My battery was 5 years and 4 months old so this was massively reassuring. Next I tested the voltage of my battery with a volt meter, it was only 8 volts. I use a C-TEK XS 4004 battery charger in the winters which is permanently attached to the battery so I put it in winter charge mode (snowflake) and left it overnight. Tested the voltage again in the morning, it was only 10 volts. Now I’m pretty confident it’s the battery.

Replacement battery: I made a note of the fitted battery: Moll Kamina 570 069 057 12v 70Ah (it also said Porsche on it). I measured the size: 190mm high, 180mm deep, 280mm wide. I also noticed that the tray it sits in has the possibility of fitting a larger battery, there were screw holes in the tray which suggested that two larger (wider) batteries could be accommodated. There were a number of posts which were useful about replacement batteries, what registered with me was ‘get a big one’, ‘get a good one’, my thinking was 80Ah should last longer than 70Ah, since getting stranded is not nice and since you don’t get any advanced warning, then longer your battery lasts the better. I saw some posts about lighter weight batteries but since I don’t race in the Carrera Cup and I weigh 90Kg before dinner the weight saving seemed irrelevant compared to getting stranded. I went to my local discount store called Makro (equivalent to Costco in the US) and bought the largest/best battery they had which would fit in the tray. A Bosch Silver S4 80Ah battery, it was 190mm high, 180mm deep and 310mm wide. It cost 165EUR.

Replacing the battery myself: I prepared my tools. A socket set, a large flat screw driver, a small hammer and a large rag. Standing in the luggage bay first I disconnected the C-TEK. Next I unscrewed the bracket that holds the battery and made sure that I could jiggle loose the battery. I needed to lever it forward a bit using the large screw driver. Next I removed the plastic venting tube from the left side of the battery. Next I unscrewed both nuts that pinched both terminal connectors. Next I removed the positive cable (levered it with the screw driver) and then removed the negative. I immediately lifted the old battery out and then lifted the new battery into position. I then connected the negative connection (used the small hammer to tap it in place) followed by the positive.

Anti Car-Jacking Siren: As soon as I attached the positive, my dealer fitted Eureca Anti Car-Jacking alarm system siren went off. This was a bit of a shock as the siren is right next to the battery and the sound was an ear drum splitter. It wouldn’t stop even when I pressed the secret key sequence inside the car. I then pressed the large rag over the siren to dampen the sound a bit while I went to look for paperwork. I found an alarm code in my paperwork and I vaguely remembered the dealer showing me where they had hidden a secret numeric pad. I keyed in the code on the numeric pad, it beeped but the alarm was still going, I then pressed the secret key and then ahh… silence. I noticed my neighbors going back inside with a smirk.

After replacing the battery: I tightened the nuts holding the terminal connectors and I screwed in the bracket that holds the base of the battery. In theory I could have got a battery one size bigger still. I connected the plastic vent hose into a little hole in the side of the battery (near the top). I tidied up the luggage bay and went for a test drive. When I reversed the car out of the drive and applied the brake for the first time the PSM failure light went out and was exchanged with a PASM failure (picture of a shock absorber), I drove 30 seconds and all warning lights were gone. I checked my radio (it’s the standard Porsche unit for a Carrera S) and no problem, radio works fine, CD works fine, no codes or keys needed. It didn’t remember the last radio station I was on but it did have all local radio stations still in memory. It could have been my imagination but all electrics worked with a little more gusto than before…but that was probably the satisfaction of having done the job myself!

 

I put my summer cars on battery tenders during the winter months. I bought a battery charger at Lowe's which has a reconditioning cycle. It puts an excess of amperage to the battery so the lead plates will buckle causing some of the sulfate to fall off and therefore get more life back. I run the reconditioning cycle on my batteries in the spring. I've had an MTP93 installed for about 3 years on a car that only gets driven about 5K miles/yr.