So my 991 sat in the garage for about 10 days and upon start up I got this warning on the dash informing me that the auto stop/start, that I always have disabled, was itself disabled. After obsessing about this for about 20 minutes I recalled that it was a low voltage issue. I called the dealer and was told that there were lots of whichamajiggers that pulled juice from the battery with all turned off. So much for parking it at the airport while I scale Everest, probably take me 3 weeks at least. Since I've got all these battery tenders from when I had multiple motorcycles I decided to install one. Has anybody here done this, cuz it appears that there are choices and I'm trying not to learn this one the hard way? I would prefer not to drill holes. Thanks for any help....Chris

 

Porsche makes a charger that just plugs into a 12 volt accessory outlet. You could also just put a battery tender lead on the battery itself. And just close the hood till the emergency catch catches. I would just get the Porsche charger it easier. I have several battery tenders too but elected not to go that way.

 

I have hooked a maintainer to the battery itself a couple of times. I took out the plastic cover and then ran the (rather thin) wires out of the gap between fender and fully closed hood.

I tried that charger's cigarette lighter plug attachment, but no luck. I didn't look into why that didn't go, yet.

 

I do it this way as well, although I don't fully remove the plastic cover. I open it enough to connect the charger and leave it in place. I put my hood down without fully latching it closed. No need to drill holes.

 

The simplest way is to buy the Porsche dual mode charger from suncoast or your local dealer.

A great alternative is to buy the CTEK 800 12V charger which IS the same charger as Porsche sells with their label on it. In fact ferrari, maserati, mercedes, bmw among others all sell CTEK chargers with their labels on it. You can buy this from amazon.com. Do a search there and find it. You will have to buy the in car 12V powerpoint adapter cable separately there but overall you will pay less than half the price. The CTEK 3300 charger or the 7xxx chargers are those with more features, but the 3300 since sold by amazon directly can sometimes be cheaper than the 800 (and I think the 800 in the 12V version might be discontinued) . Make sure to buy the US versions with a US suffix.. ie CTEK 800 US or CTEK 3300 US if you are in the US.