Christer

Riccardo

I think this is called 'clutching at straws'. If you charge (not trickle) the battery overnight (say 8-10 hours) it should store plenty enough power to start the car and then some. If this isn't working I would get a replacement and not waste any more time on it.

Rich W

I tried the battery selector at the Optima website. They don't have any matching batteries for 964 applications.

Anyone know why?

Randall G.

Hi Rich,

I had the same problem with Optima's battery selector. However, I can say that the 75/35 redtop should fit your car. This is based on the 964 and the 993 batteries sharing the same part # (per PET) and the following threads from the 993 board:

<a href="http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic;f=3;t=006937" target="_blank">Thread 1</a>

<a href="http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic&f=3&t=006932#000011" target="_blank">Thread 2</a>

And, from Greg F.'s link in the above thread:

<a href="http://shop.store.yahoo.com/rodi/opbat720cca.html" target="_blank">75/35 Redtop</a>

If it was my money (but it's not!), I would go forth and buy the 75/35 redtop. I happen to know what should be the proper battery, as I have it pre-researched, for when my own battery dies.

Randall G.

It looks like you can get a much better deal ($40 cheaper) on the 75/35 at <a href="http://www.batteryweb.com/optima.cfm" target="_blank">BatteryWeb.com</a>, as compared to the link above.

Emanuele Ferry23

Something similar happened to me last summer. I had a current drain from engine bay light which completely discharged my battery. It was a sealed FIAMM premium. I had it recharged but with no success.
My mechanic told me that it's a possible (but not common) problem with sealed batteries. However the battery came with three-year warranty and it was replaced with a new one for free. Apart for this episod, I'm very happy with this battery.The price is about 120 Euros, and it fits 964 compartment.
(http://www.fiamm.com/en/1/prod.php/1;3)

Bob Krantz

Let me strongly endorse Randall's recommendation for Optima batteries. The truly sealed construction means not only no acid spills, but no out-gassing (also can lead to corrosion). Plus, they do not seem to die. I have an old one that served first in a street car, then a couple of seasons in a 914 race car (talk about abuse), then in a car trailer as power for winch and lights (with many deep discharge/charge cycles), and now as a back-up in the garage. It still holds a charge. I have a new one in my 964. Installation can be a challenge, especially if you want to keep the original cables--check out my Running Reports piece in the June 2002 Porsche & 911 World mag, or look on John's 964 web site (www.porsche964.co.uk).
Bob K

Randall G.

Hey Bob,

Read your install on John's site. Looks to me like your install was complicated a bit by using the Odyssey battery. The 993 guys say the Optima redtop 75/35 fits just like a factory battery.

Anyway, bet it's nice knowing that you won't have another one of those battery acid spill incidents.