GraSox

I have a 06 997 4S and want to replace my battery. I've researched and it is VERY confusing at best. The dealer told me I need a Interstate MTP-93 which is a little bigger. I just need to use one of the "other 3" holes in the battery tray to attach and put a nut under the tray to attach the bolt.
Well, I get home after buying the battery and guess what? When I undo the clamp holding the battery down there are NO OTHER holes other than the one for the stock clamp and you can't even get underneath the tray to try to attach the nut!
Why is this simple project so complicated????? I spent hours searching this.
Do some P-cars have trays w 3 holes and others don't?
Why so many different batteries to fit a 997??
Please help guys, as this is very frustrating. TIA as always

okbarnett

I use the advanced auto parts battery, it fits exactly

current47

I had the same problem (a few times). I had my car in the garage without the trickle charger and this past winter was brutal in NY area. I had to replace with MTP-93 and there was no hole that aligned for that size. My suggestion is to return it and go with the MTP-91 (that one fits perfectly).

JasonKM

actually the correct replacement from Interstate is an H7. Other battery manufacturers number is 94R, which is a direct fit replacement with spot for vent tube. Best deal most have found is Wal-Mart. Battery is Max 94R and retails for about $80 and has a 3yr replacement and 9yr pro-rated warranty.
Wal-Mart battery is made by Johnson Controls. I have installed them in a couple of 997s in the last year (my 2007 C4S and a friend's 2008 S)

jhbrennan

+1 - Maxx 94R is a direct replacement - perfect fit using exisiting hold down clamp + plus much better warranty that Porsche - no BS about driving car 6,000 miles a year or no warranty.

sjfehr

Replacing your battery shouldn't be difficult or confusing. Just go to Wal-Mart or any auto parts store, use the book/computer (or ask a person who works there), and buy the battery they say will fit your car, because Porsche uses standard-size batteries, and the battery they sell you will almost certainly fit your car just fine.

Most auto parts stores will even test your old battery (to make sure it actually needs replaced) and install the new one for you for free.

KeninBlaine

When I thought the dealer might tell me I need a new battery earlier last week, I checked the Walmart site and they showed no stores in So Cal had the Maxx 94R. Lucky for me, I didn't need a new battery. The problem, as I expected, was in the well documented problem cable between the alternator and starter, and was covered by the CPO warranty on my 06 C2S cab. The car cranks twice as fast now as it used to.

BTW, when I couldn't find a MAXX 94R, I checked out prices on the Interstate MTP H7. The cheapest place I found was Lessco Electronics at $148 shipped. That was cheaper than any other place I checked for that battery.

NA011

My '06 had the extra hole but it was not threaded. I put the nut in/on the box wrench w/ tape on the bottom to hold the nut in place. Put a drop of Loctite on the thread & tighten it up.

Musclehedz101

+1 on Walmart's Maxx 94R EXACT OEM replacement at better cost and warranty! Dropped on in my 07' C4S last fall.

NA011

Here is a picture of the tray showing the non-threaded hole. This should give you an idea on what to look for. The picture came from a Rennlist post on the "Optima" battery.

GraSox

As I said I don't know why I don't have the "extra" holes in the battery tray on my 06 4S. Otherwise I could have used it as suggested. Also< how could you get a nut under the tray to thread the bolt into? It lays flush on top of the metal it rests on.
What am I missing here?

JasonKM

DO NOT GO BY THE PARTS STORE BOOK!
many part stores will list a size 49 battery, which is about 2 inches longer and the bracket on the battery tray will not work (i.e. not threads in the hole). As suggested, ask for a size 94R battery. It's a very common size battery for german cars such as the A4 and A6. Chrysler also used it in many vehicles

function12

Plus 1 the computers are WRONG!! Bring in your old battery to match the size.

utkinpol

i had issues with my old battery loosing charge in winter so i came to autozone and got largest one they had showing up in the computer. it took 5min or so.

it is wider than one you have in stock and somewhat 7-12lb heavier and you need to move that bracket in the base where battery sits - just undo 2 bolts. takes about of 10min of work.

i am not fond of small batteries for 997 cars - if you do not drive it everyday and it sits in the garage for couple of weeks sometime you do need plenty of capacity so it would not discharge when you least expect it.

PS. YES it is a non-treaded hole, SO WHAT? Get a bolt with a nut. Big deal. Autozone has it all. I really do not remember details now but i got it all done with no issues while i was outside of autozone store, not even in my garage.

current47

i am sticking with MTP-91.. been there got the t-shirt and the ash tray.. IMHO..