I called Odyssey and they told me I need the 1700MJT, which is a monster (61 pounds!).
http://www.odysseybatteries.com/batt...1700series.htm

Holger, depending on how big a hurry you are in...I ordered an optima yellow top and bracket from Fabryce and they should be here today or Monday...when they arrive I will do a diy with photos and then you can decide...

Just got the Braille 15lbs and the battery mount. Have did you install this mount to the battery bay?

I got this
http://img125.imageshack.us/img125/8...generalyl7.jpg

http://img512.imageshack.us/img512/7...4detailmm8.jpg

How do you take care of the battery when not using?

Is the GT3 significantly different compared to other 996s in terms of battery requirements? Just wondering why Rennline had it as their 996 battery.

Thanks, Chuck. I think the new plan for me is to just get a generic battery for now so I can drive the car and then look into a better solution later.

Remember, the dealer told me they put a smaller battery in the GT3 than all the other 996's due to weight. They use the smaller Moll.

I took NJ-GT's advice and got the Optima Red Top 35 from Costco.

Why do I need European Adapters? The posts on the top don't work? I'd appreciate it if someone could post a pic. Thanks.

the euro adaptors are for mounting the battery not for the electrical connection...they are free from Optima....you might also need longer cables if the posts (+ and -) are reversed or are in a different position because the stock cables have no extra length....those are available from GMG

I found a retailers web site that lists all the Optima batteries, their specs, size, configuration etc. The prices seem great and "free shipping" was displayed. I bought from Advance Auto but wish I had seen this site at least for info if not to order.

http://www.1st-optima-batteries.com/

Optima sells three batteries that would seem to fit with the positive located towards the left and back along the firewall side of the compartment. *this seems to be the big thing to look for...configuration, or how the cables connect*
Two are red, the 34R and 35. The yellow that fits is the D35.

The lightest of the three is the Red 35 which is also the cheapest
The yellow D35 will survive the most deep cycles, storage, etc
The red 34R has the most cranking power, weight and size.

The style of the batteries is such that the cylindrical tubes (six pack look) vs rectangle does not work with the clip the GT3 has to bolt the factory battery in. The european adapters we have been talking about simply conform to the shape of the base of the Optimas six pack figure and provide a lip to then bolt down with the factory clip.

They do not make this european adapter for all batteries, I know they do for a few such as the Yellow D35 I bought. Problem is, it is pretty flimsy anyways.

I ordered the battery hold down from GMG and will shoot a pic when it comes in. I do not feel this European adapter is a good strong design but could be suitable for street driving.

Cost me $130 +tax at Costco for the 35 Red Top.

I'm guessing the European adapter is that plastic crap that came on top of the battery that can be used for the battery to sit on. No thanks.

Don't laugh too hard when you see the pics of how I mounted mine (temporary, I think). I scrounged around the house and found some metal spacers that I wedged between the base of the battery and the firewall side of the tray. Then I laid two of those down to push the battery over towards the passenger side and used the stock hold down. It's in there tight now, couldn't get it to budge. But just to make it PCA legal ;), I added the bungee cord. I didn't even have to break out the duct tape or chicken wire! Just call me Cooter...

Holger, you got the Red 75/35 which is a different configuration than the Red 35. You made it work and the only reason I mention this is because there are so many freakin' battery classes/configurations it is confusing.

The only three that are configured exactly as our OEM battery is are the:

Red 34R 50ah 800cca 1000ca 10"x6.8"x 7.8" 38.8 lb $159.00
Red 35 44ah 720cca 910ca 9"x6.7"x7.8" 33lb $150.00

Yellow D35 48ah 650cca 810ca 9x6.7"x 7.8" 37.2lb $176.00

The european adapter is not the plastic tray that came on top. That is if you need to elevate the battery. You need to order the adapters if you want them.

As you have shown, you can make other batteries fit but the cables do not have a lot of play. If you want a replacement battery that has posts in the same place as the stock battery you need to go with one of the three above.

If you want to really secure an Optima you probably need a tray like GMG sells. Mine is in the mail. Pics when it gets here.

CT, you're right, I stand corrected.

It was the only Red Top they had at Costco. The only real difference seems to be the posts between what I got and the 35.

No problems with the cables.

It's fine as is for street driving, but eventually I'll get a better bracket like GMG's or fab something up myself.

Someone posted that the OEM weighs 35 pounds and the website you listed indicates 33 for the Optima. Felt like a bigger difference in weight to me than 2 pounds when I swapped it out.

My battery is on its last legs too so I've been following this thread closely. Too bad about the Odyssey. :(

As for brackets, GMG sure isn't giving away their mounting system. Sometimes I'm really glad I own a welder. ;)

Cheers,

I hope my Optima arrives tomorrow cuz my Moll just gave up the ghost even after being on the trickle charger for several hours last night...at some point the Molls just don't hold a charge anymore...I wonder how you say "planned obsolescence" in German...at least I didn't have it locked so getting in the trunk was no problem

Lb for lb, these Optimas do not have a good ah capacity.

Regular batteries have a usefully higher ah capacity with as much cranking power as the Red Top/Optimas, and at relatively similar weights.

My current Varta Blue has served me well over the past 30k miles and 2 years years. I'm looking at the Varta Silver as a replacement which is about 18kg for 77ah 780A. It's not an AGM battery, but I haven't had any issues with the Varta Blue... Usefully cheaper than the RedTop/Optimas too...