Macster

That leaving the ignition on with the engine off is only for those cars that have some kind of special alarm installed. I forget the option code. Common in the UK. Not so much over here. But the OP should double check, consult his owners manual for the proper battery replacement steps.

Luxter

More details please?
Thx
=LL=

Vancouver-BC

I replaced my battery last summer, left the trickle charger plugged and didn't trip any codes. As others indicated just be careful with the battery cables. Picked up a Porsche OEM battery for my 997 C2 from Sunset for ~ $150.

gabe2006

Anybody knows what the Audi OEM battery part number is? Or other ways to identify the correct size?

jhbrennan

Just go to Wal-Mart or get an Interstate - both will be better than the Audi (or Porsche for that matter) and with a warranty that works - no 6,000 mile/year requirement.

RennlistTomE

Wherever you buy the battery, especially if from WallyMart, have it tested before you leave the store. These things can (and do) sit on store shelves for months. And who knows where they are in the supply chain before that.
It's cheap insurance.
When I changed my battery six weeks ago ('09 Targa) it didn't lose data / throw a code. No problems at all.

7500rpm

For 997.1 info, the workshop manual actually has a procedure for the window as mentioned above as well as the PSM light going off after a few seconds. IIRC, it also stated turning the key to accessories (not starting) position for 30 secs for the computer to set some stuff like throttle position, etc. However, there's also a final procedure that requires you to drive in the straight ahead position for 20-30m (can't remember but not very far) to let the computer know the steering position. I've replaced several batteries, never did the last step but suspect it affects PSM somewhat. It makes sense that the car would need steering angle to decide on ice mode, ABS control, stability intervention, etc.
The best thing to do I guess is not to remove power completely by putting power thru the cigarette lighter or thru the fuse box and door jamb.

Minok

Finally replaced the Moll in my 10/2008 Targa this past week with a Walmart Everstart Max H7 ( http://www.walmart.com/ip/EverStart-...ttery/20531542 ) sized one. Swap went off without a hitch. Standing in the frunk makes the remove and insert process simple.

Though I don't understand why they need to use 2 different sized bolt heads on the system. Could the hold down clamp not have the same size bolt head as is on the damn battery cables ?

But I have one question re gas venting. Inserting the vent hose to the new battery was easy. .but for the hole on the other side.. do I need to plug it? The Moll OEM battery has a white insert in there.. but the Walmart battery came with nothing. Did inserting the vent line pierce a membrane so all venting happens to the side with the vent line plugged in.. or should I be looking to seal that opposite side vent hole with something?

Doing some digging I found a post from a supposed Everstart expert saying "There is a plug molded into the cover on the positive post to plug the unused hole. " ( http://answers.walmart.com/answers/1...estion=1007557 )
So I'll have to look at the plastic covers when I get home to verify I've got a usable plug there I can pop off and insert into the opposite side vent hole. This is my first vented battery system, so its all new-to-me.

Iceter

My Interstate did, in fact, have a plastic, throw-away cover over the terminals. Molded into one of them was a plug for the unused vent hole on the driver's side. It would be VERY easy to miss and in fact, if I had not read about the vent tube on this forum, I would not have connected anything to my new battery because I would have missed the plug and the vent tube had fallen out of my Moll and down out of sight. I would not have even looked for such a thing.

If your Wal-Mart battery didn't come with one, see if the one pressed into your Moll battery can be pulled out with pliers or a small screwdriver and re-used in the new battery.

gray911

Why replace it? I'm still with my OEM battery after 5 years. Still starting strong even in subzero temps like this morning here in the St. Louis area.

chris.hanle

Gray911 you are the exception. I go through batteries about every 3-5 in all my cars. I hope you didn't jinx yourself. The weather here in Tulsa is just about same.

targaC4S

I wanted to replace mine since it's from early 09 but it tested good at 850cca. Which is weird because I think its only rated at 700cca.