Hi All, I own a 996 Turbo and love it but I am considering either the 991 GTS or 991 Turbo or maybe even the BMW M4 (sorry)

The battery is my problem....

I need a daily driver car. The 996TT is fine but as I work from home, I don't usually drive far for anything and occasionally I will take the long and curvy road, just for fun. Sometimes the engine doesn't even get a chance to warm up. As well, I travel much and at times for 2 ~ 3 week and before I leave, I must disconnect the battery otherwise when I am back, it is dead... again.

And because of this, my 996TT ate quite a few batteries.
I have tried to keep the car locked and unlocked and the result is the same.
The car is kept in a garage but there is no AC power so I can't use a trickle charger. I have an AC source on my drive way but I don't want to keep the car there.

Does the 991 have the same problem? BMW told me I can leave the M4 for 2 ~ 3 weeks and no issues for the battery.

I need a car that I can just get in and go and it should be sports car / performance oriented.

Thanks for any input.

 

I am not sure of anything you can leave for prolong periods anymore. There are just to many electronics going on in the car even when turned off. For the cost of the batteries, have you looked into getting a outlet wired into your garage, can't be overly expensive and would pay for itself in batteries. Then you can use a battery tender.

 

I asked the same thing to my service advisor as I'm sometimes gone for a couple weeks at a time for work too. He said that the 991 has a different style of battery from the previous gen cars and it lasts much longer.

The advice was to lock the car up and not worry as they've seen cars last up to a month without being started and they cranked just fine. Obviously best practice would be to leave it on a charger, but in absence of it a couple weeks shouldn't be a problem. I know personally mine has gone two weeks between starts and the battery was fine.

 

I am not able to pull a line to the garage, that would resolve my problem...

@ Panacea
And yes, I also read that the 991 has a different system now compared to the 996/997 and after a few days the electronics will shut down. I was just curious on real world experience.

After 2 weeks did you notice low voltage on the meter?

 

With start/stop came AGM Batteries.
So the new batteries are better.

However, they still put a small 70AH batterey in the car, probably to save weight.

The tray will take the 2 sizes up 95AH battery, which is what I put in my car.
The weight penalty is 15lb.

Buy the Porsche AGM battery. I can send you the part #.
Then have the dealer code your car for it.
(They need to scan the barcode.)
That seemed to extend my Stop time with Start/Stop but that was not my goal.
I just wanted a strong reliable battery.

If you dont care about getting coded (no need for barcode) you can get an Odyssey AGM battery which is an even better AGM battery.

I bought the OEM to get coded and then switched to the Odessey.

When I tested batteries the Odyssey tested higher for CCA and it seems to indicate more charge level on my battery monitor (part of my permanently wired charging quick connector).
The monitor reads level via 3 led's. Odyssey is green much more of the time, than OEM was. OEM was always yellow and never green.

My car can sit at least a couple months without starting. Probably even 4-6 months.

 

lunarx - what is the purpose of coding the car for the battery?

 

Good question.
My Shop Foreman seemes to be the only person who knew about it. Service Advisors will probably not know about it.

The only thing I can say I noticed is that the Start/Stop allows the engine to stay stopped, for the full duration of a signal light (longest I tested it) where it used to restart in 30s (if it even shut off).
In addition to that, I can only speculate, that the alternator charging routines might be adjusted (my SF may have hinted at that).
As another benefit, I am not sure if I get more accessory run time, after engine shut-off, but I think I might have a slight improvement there also.

I admit the Start/Stop thing is not a motivator, but at least if I ever want it (like when ordering in a drive thru) it will work properly now.

Initially I had the 95AH w/o coding, which seemed to behave same as before. So the coding seemed to do something.

 

Start / Stop? I have it in my BMW 5 and I absolutely hate it! I really don't see the benefit, giant battery in the back, no spare tire... that's another story. So, if I change to the 991, NO to start/stop.

Also not sure about this coding thing... I just go out to the local parts store (much closer than the dealer) and pick up a battery.... didn't know about coding....

Ugh... what to do...
Even to decide which 911....

 

if you have a light bulb or a garage door opener in your garage, any electrician can set you up with an outlet. You can even hook up an extension cord from the light bulb socket by using an adapter.

 

Which 911 is definitely a tough decision

I hope you won't get a local Auto Parts Lead Acid Battery to replace your nice AGM Porsche battery.
You would be better off keeping the original battery.

I hear you on Start/Stop.
No worries, it stays disabled, via a one-time button push.
Mine is always off, except for the rare occasion when I think it may be useful

 

what about a solar trickle charger....if your garage has a window.

 

Thanks for the suggestions folks. No window, no outlet of any sort.... so I am stuck.... unless I build a new car port or garage.... wife might flip as this will mean taking out some bushes and so on.

Yes, just a standard after market battery.... did the 996TT come with an AGM battery?

I am leaning to the GTS but after having a TT and then buying a GTS... seems like a let down... I would like to go with a more livelier 2 wheel drive than a 4 wheel drive.... at least that was how it was with the 996. The TT steering was much heavier than the Carrera. Is it still the same? Time to test drive....

 

I would do the solar route...cant be too difficult to drill 1/4" hole thru wall after determining best solar location..i think 1/4 is like 6mm

 

That is a great idea!!!! Thank you!!

 

Something like this...? http://www.maplin.co.uk/p/solar-powe...-charger-l58bf
Because the wire needed might be longer than supplied, maybe I will put 2 panels in serial...?? Time to call the local parts dealer.