996 New Battery

[Peter642]

Howdy,

Long time since last post.

I need to change out my 2003 C4S battery, and looking both online and in the forums unfortunately only has me confused, and the original owner’s manual and paperwork, all of which I still have is absolutely useless on this one. It quotes lightbulb sizes, but not battery size.

The old battery is an Interstate Group Size 91, with a vent tube.

The internet claims that the 996 can handle Group Sizes 90, 91 or 92, which are equal to Sizes 47, 48, 49, respectively. From what I see, the difference in size, from smallest to largest, means more cold charge applied.

The internet also claims that my battery can be “updated” to a sealed (tubeless) battery, or a top-of-the-line AGM, if I want to pay.

So, here’s the question(s):
1. Does size matter? Should I stick with the 91, or upgrade to what most car part stores are recommending (a 94R is what Napa and AutoZone recommend).

2. Do I need the vent tube? Can I upgrade to a sealed battery instead?

3. Is there a “best” or “right” answer to, “what battery belongs in my 996?”

If I had to guess, a sealed Group Size 48 / 91 would be just fine. Yes?

Thanks a ton,
Peter

[JFP in PA]

The AGM battery is the way to go, no maintenance or corrosion issues ever. Something like the Duralast Platinum Battery H7-AGM Group Size 94R 850 CCA or Optima 34R 800 CCA is correct.

[Peter642]

Thanks; will go with that. Much appreciated.

[ADVer]

Wouldn’t an AGM battery still need to be vented?

[JFP in PA]

Originally Posted by ADVer

Wouldn’t an AGM battery still need to be vented?

No.