Replacing the cable is dealer speak for the nuts are loose/corroded.
They figure while we're in there ......

 

Robert is no longer at DFC presently due to Covid staff reductions ..Just spoke to him a few weeks back ... PM me if you are interested as to where he is presently working not to mention the shop he is at does excellent work ..... I highly recommend them all prior DFC and Pfaff trained techs and where I take my car.

You may not have a cable issue ..My 3yr old Bosh oem battery was just getting weak so I replaced it with a Odessey 840 CCA AGM battery and no weak or starting issues what so ever ... Our cars should have at least 800CCA battery in them and anything less just ends up causing issues or dying prematurely I have found.

 

I had it done on my 2008 C4S and it was $1200 at Porsche Oakville.

 

How long ago was this if you don't mind me asking. Was it just the cable or did you replace anything else while you are at it?

 

I can't see how your battery drain would be related to a corroded starter cable. I think you have two separate issues. Look for the parasitic draw before you do anything else.

 

I think I would start with the simple things first.

1. Do you lock the car when not in use? Historically, I don't lock my cars. The Porsche always gets locked due to it being in some sort of active mode and will not sleep causing voltage drain.
2. Your battery could be a dud. My mopar battery in my jeep died. 8 volts. No sign of degradation. I suspected bad cell.
3. My 996 is always on the trickle charger when not in use. I go weeks without driving it. I have a porsche battery.
4. I trickle charge most things when not in use. ATV all winter, boat batteries over the winter, riding lawn mower is always on trickle charger. I find this avoids alot of issues. The undersized battery in my mustang lasted 10 years. Was trickle charged when not in use.
5. Load test the battery.

 

They replaced the battery as well which was additional to that...can't remember exactly but it wasn't horrible.

 

There are several write ups on this topic ..... There is also a Porsche TSB on the cable connection post corrosion that causes this symptom. This is an easy issue to diagnose write up's all over the place for this topic.

Start off by watching this -