bart1

Odyssey > Optima, well except for weight and size. I have a 925 and no need for trickle charging. I drive it a couple times a week at least and have it in my garage, alarm not armed.

http://www.odysseybatteries.com/battery/pc925series.htm

Peter Zimmermann

I bought a DieHard Group 48 for my '82 SC in Nov '05. It was $118 including tax, and has an 8-year warranty. It has been excellent, even holding a charge for longer than a month of non-use during our awful summer months. I do have a battery charger, and I do trickle charge it when I think about it (sometimes weeks pass without attention). There is zero corrosion along its top, or on/near its terminals. The battery uses the stock hold-down, in the "short battery" position, and is simple to remove if necessary. The terminals are placed the same as the original o.e. battery. So far, so good.

sig_a

33.5 pound Group 90 DEKA 690 MF at about 9 9/16 inches in length using a "stretched" standard battery hold down from the short battery position.

Vino

Just to add, if some still go for the acid filled batteries, why not get a battery mat to soak the acid just for precaution.

My car is an 87, owner said he put in maybe 4 or 5 batteries in its life and the underpan where the battery sits on top of was perfect, he never put anything under the battery.
I was getting scared after seeing some pics of 911's with all the corrosion in the area.

Someone had mentioned having the battery on a trickle charger and a switch for drycell batteries.

I have both a Batterytender that I use for the 911 and a Ctec for our Cayenne Turbo. Only the Ctec can be used for the Optima batteries from the two I have. There may be others but do some research if you use a trickle charger since I belive the Optima is near $200 + special charger like $70.

JackOlsen

I use an 18-pound battery designed for a wheelchair. It was $43.

Brads911sc

I use the interstate. Its 4 years old. no issues. Not sure why all the hype on optimas unless your racing. If you clean and maintain the area.. shouldnt have any issues with using the battery that was "made" for these cars. Cant really go wronk with a Diehard or Interstate. Just my .02 cents.

KC911

Technology advances. Lots of things have been improved dramatically over the past 20-30 years...tires, batteries, oil (synthetics), polybronze bearings vs rubber bushings, etc. Batteries are batteries and not designed for specific cars (even though they may slap a Porsche sticker on them). When you have been through as many batteries as I have over the years (many different applications), you tend to learn a few things along the way . Plus, weight savings are important to some us...but to each their own.

ps: I noticed in some of the batteries pictured in this thread that some don't have a cover over the positive terminal...cheap insurance against a potential fire hazard imo.

ajmarton

On the OEM battery - were the terminal posts on the side or on top?

ron mcatee

Top.

3.2SLANTNOSE

For what car and what battery group?

I can only speak about the OEM batteries for a few different years on new 911's that I have had, the post were on top, and had a protective cover over the positive terminal. The same type batteries was also used on the German made(up to 1979) VW Rabbit Diesel's. After the 1979yr models, the Rabbits were made domestically, and the quality went to hell. The easiest way to tell a German made Diesel Rabbit from an American made Rabbit, was that the German made, had round sealed beam headlights, while the American made had the big square headlights.

Yesterday, I had to replace the battery in my BMW 750iL, V-12. It takes one of the monster sized, group 49-1 batteries. The BMW has a factory, built-in, battery vent system, to make sure that the out-gassing, or any fluid from the battery is vented outside the car, being the battery is located under the right side, rear power seat bottom. The Group 49-1 battery, is also supposedly usable for a 911, but I believe that I would go with a group size 47, 48, or even with a 93 battery due to their smaller size, and lighter weight, with almost the same power specs, but just not as HUGE, as the 49-1 battery. So you have several choices in choosing a new battery for your needs. Good luck!! Tony.

Tippy

I have an Interstate and thing will never drain down.

I have had the car down for months at a time and everytime the stupid thing is still charged and starts the car. What a fluke......hehe

newsboy

Do you need a special charger for an Optima battery? I have a regular charger which has the following options.
1. 6/12 volt
2. manual/automatic
3. Regular/Maintenance free

Also, will a battery maintainer work on the optima.?

LaughaC

I considered one of these 4 lb batteries until I saw the price... $1200!!

http://voltphreaks.com/

Houpty GT

I bought my '81 911 came with a group 49-1 Advance autoparts battery. The battery will fit in the location but is difficult to maneuver it in just right. It did not come with a hold down and after I bought a hold down I found out why. It does not simply bolt in. The night before an autocross I spent about an hour attempting to get it in and just managed to turn the bolt but could not tighten it down. The bolt ends up being to close to the hold down to get a socket on it and it has to be turned at an angle. Anyway the battery is approaching 6 years and has eaten away some of the battery tray with acid. I don't see any tubes for the vent connection in my trunk either. I am really considering an Optima.

Will the optima batteries not bolt straight in?

sig_a

"Will the optima batteries not bolt straight in?"[/QUOTE]

I think you need to either buy a hold down kit or fabricate one.

This is the way I did it. Lighter weight (33 lbs.) and way cheaper than Optima. The only thing you have to design and modify is the hold down bracket, which is cut and extended -- see photo.

DEKA battery is manufactured in US by East Penn Manufacturing...battery supplier to NASCAR!