so, I'll be going on a 2 week trip with the 991 in the garage. Wanna ensure my battery doesn't die as I know these vehicles seem to burn batteries when sitting by itself. Any tips for keeping my 991 alive? Should I leave the battery charger in?


http://www.suncoastparts.com/product//95504490054.html

 

2 weeks should not be a problem. I've left mine sit for up to 60 days without any problems.

 

Agree that 2 weeks shouldn't be a problem. Mine hasn't been started for 3-4 weeks at a time and fires up no problem. You can of course take extra precautionary measures but I think you almost definitely will be fine for 2 weeks.

 

I wouldn't sweat it.

 

60 days and you didn't have any battery drain problems. Is that right?

 

If you live somewhere cold, it might be a good idea to hook it up to a battery tender but since you are in California I wouldn't bother.

 

Ugh, I just went into the garage today to start up the car for summer, and the battery is dead. Turns out the battery tender tripped the ground fault on the socket when the power went out months ago. Do I jump start the car now, or simply just plug it back in?

 

Unless you are in a hurry to start the car, don't jump start it.
Just plug your charger in and let the battery recharge.
The battery is a good quality AGM, so it should be able to recover from this full discharge.
Because these are AGM batteries, you should be using chargers designed for these types of batteries.

 

I use the Porsche battery tender.

 

i was away 2 months and the car still started.

 

I've done 2 weeks without any problem !

 

No, as others have said, 2 weeks isn't a problem at all with a relatively new OEM battery. It could be a problem with an older battery nearing retirement, but even then it should start ok after 2 weeks.

Wow that's impressive! I still wouldn't do that since every time you do it'll significantly shorten the lifetime of the battery.

Since it's a relatively new battery, you should be fine if you put a charger on it. If it was a couple of years older it might not take a charge at all.

You don't want to use your tender to try and charge a battery because it's not a charger, it's a tender. Some chargers also have a tender feature, and even though some call the Porsche Battery Maintainer a charger, it's not. You can easily tell if a something is a charger because it's going to be very heavy. My smallest one is about 12" wide x 10" deep x 8" tall (about the size of two large tissue boxes placed side by side) and weighs probably 30 pounds.

Since the battery is totally dead, your charger may not be able to charge it as-is. Chargers need to sense some voltage in the battery in order to charge them, but how much voltage is required varies between manufacturers and charger models/sizes.

People think the battery is totally dead and can't be charged when they hook up their charger and nothing happens, but there is a solution. Just take the battery out of the car and hook up another good battery to it in parallel with a set of jumper cables. Then hook up the charger to the dead battery. The voltage from the extra battery will fool the charger into thinking there's enough voltage in the dead battery and it'll start charging. You can usually unhook the extra battery after about an hour and just charge the formally dead one. However, if it's an older battery (5+ years old) this trick may not work.

That's actually a common misconception. AGM battery manufacturers recommend using the regular charging mode. Some expensive battery chargers have an AGM/gel setting, but those two types of batteries have very different charging requirements, so having one setting that charges both correctly is impossible. Hence why they recommend using the conventional/normal setting since that will work fine on an AGM or gel battery and won't cause any issues.

What year is your car? OEM battery? I've had two 996's and the OEM battery in my first one would usually last about 3 weeks. I bought a new OEM battery for my current 996 and it's about 8" shorter than the old one which is easy to tell because of the gaps at each end of the battery box. It's about 2 years old so I assume it's a late 997-era battery. I've never had a chance to test how long it could sit and still start since I always hooked up a maintainer to avoid killing it and having to buy a new one again. I've only found it has a lot more trouble starting in the cold than the older ones did.

 

Get in the car, put the seat belt on and turn the ignition on (but don't start the car). If you can maintain 12.0v or better for 2 minutes you should be okay.

ChuckJ

 

No charger necessary! I leave my car in the garage a lot longer than 2 weeks sometimes and it always starts.

 

Not necessary for two weeks in our climate but also not the worst idea. A good battery tender is a good investment anyway.