Porsche 996/997 battery and central locking
If you have a Porsche 996/997 and have left it unused for a week or more, there’s a fair chance you’ll have had problems unlocking it.
This is normal – the remote central locking shuts down which means that you have to use the key to open the driver’s side door. When you do this, the alarm will sound and you need to use the remote fob to silence it. Annoying for your neighbours!
However, if you leave a Porsche 996/997 for a long time, the battery will run down, because the alarm system is always drawing a small amount of current. Again, then, the only way in is by using the key in the lock. However, on later facelift 996s and all 997s you then have another problem – the battery is located in the luggage compartment which is opened via a switch next to the driver’s seat. And this needs electricity to work.
Porsche anticipated this problem and included an emergency power point in the fuse panel in driver’s footwell. Remove the cover and pull out the red positive post. You can connect a booster pack or battery charger to this – the negative lead can be clipped to the metal door catch. This won’t allow enough power to start the engine but it will let you pop the luggage compartment lid open, and you can then charge the battery properly or connect a boost pack to the battery terminals.
If you don’t drive your Porsche 996/997 regularly, you can avoid this problem by using an intelligent trickle charger, which can be connected either to the battery directly or via the cigar lighter socket. An intelligent charger monitors the battery and keeps it fully charged, unlike a simple battery charger which can overcharge a battery and can be a fire risk.
I use CTEK chargers which are small and neat, and are also used by Official Porsche Centres (you can even get a Porsche branded one). These come with a choice of the usual crocodile clips to connect to the battery or a trailing lead with a socket at one end. This can be permanently attached to the battery and you can simply plug the charger into the other end when you put the Porsche away in the garage.
If you keep your Porsche on the street, then you can get little solar powered chargers that sit on the dash top, but I’ve not had experience of these.