After a warranty renewal inspection in late November 2008, I was told by the OPC that the 4-year old battery (presumably the original factory fitted one) was shot, with one-cell down (not that I had noticed). As the warranty renewal requires a Porsche part is used, a new (Porsche / Moll Kamina 580 42) battery was fitted. At the time I was miffed but not especially upset as I expected to see at least 5 years of use.
Fast forward to last month, two days after a major service as it happens, the alarm was triggering intermittently and the electrics were going haywire whenever the car was unlocked. It wouldn't turn over when started (just triggered the alarm) so I checked the battery which I was surprised to see was reading just 7V. I charged it overnight and all of the next day but the voltage wouldn't get beyond 10v. Cue new battery - after just 2 years and 5 months!
As the car is under a Porsche warranty I was forced to shell out another £195 on a like-for-like replacement. Once the new battery was installed, I checked to see if there were any excessive current drains - and there weren't. The alternator was chucking out 14.45V when the engine was running, which is normal.
I'm very careful to check electrolyte levels from time to time and test the SG before the winter And, whenever the car is parked up for more than a couple of days, I connect up a mains-powered conditioner or a solar-powered maintainer, so I'm sure the problem wasn't caused by neglect. Other vehicles in the fleet have a 6 year-old Bosch (BMW), a 5 year-old Exide (Land Rover) and a 9 year-old Yuasa (Honda) fitted , all still going strong.
The conclusion is that Porsche's quality control standards aren't up to much, particularly when it comes to batteries. Expect between 2 and 4 years from a Porsche/Moll-branded battery at £195. Expect double the life from batteries costing half as much.
It amuses me to think how Porsche think they'll manage with hybrid / electric cars [
]
