It wasn't an Optima battery, but the last battery I got for my 964 was a supposed sealed cell but it still came with a vent nipple on it - if you get a correct Porsche specific battery.

The amazing thing, Walmart of all places had a 911 battery in stock.

 

Unfortunately, OPTIMA does not offer an exact-fit replacement battery for every application. You can measure the dimensions of your existing stock battery to see if there’s an OPTIMA that will work for your vehicle. Below is a link to the product specification page where you can find exact dimensions for all OPTIMA batteries:

View the products spec pages to find the exact dimensions.

YellowTop
http://www.optimabatteries.com/optim...wtop/specs.php


RedTop
http://www.optimabatteries.com/optim...dtop/specs.php

Alternately, you can check the Internet enthusiast forums for your vehicle to see how others have done custom applications with OPTIMA batteries.


If you are using an OPTIMA battery in a custom application, it is important to consider the following:

1.Hood Clearance – There should be at least ¾” clearance between the top of the battery terminals and the underside of the hood.
2.Trunk/Interior Mounting – If your battery is mounted inside the passenger compartment or trunk (common in many European makes), the battery must be vented to the outside of the vehicle. OPTIMA group 27, 51, 78, 34C, and 31 batteries all have ports for connecting a vent hose.
3.Side Terminals – OPTIMA 34/78, D34/78, 75/25 and D75/25 batteries have both top and side terminals. If you are using one of these batteries in a vehicle that uses the top terminals, it is important to ensure that the side terminals can not come into contact with anything metallic (for example, the firewall or fender well), thereby causing a short. Suggest keeping the post protectors on the terminals you are not using.

When used with a properly regulated constant voltage charging system (such as an alternator) the OPTIMA will usually not emit hydrogen gas. However, gassing can occur when charging at higher voltage levels or in extreme high temperature conditions. In automotive applications this typically will not happen if the alternator/regulator stay below 15 volts

 

Yeah and the Titanic wasn't supposed to sink either.

 

See this thread I did several years ago:

http://forums.pelicanparts.com/porsc...ima-power.html

 

Thanks Ed and at a great time. I need a new battery

 

Thanks for the additional info guys. Dave, I should have read through the FAQ on Optima's site, sorry to make you do the research for me. Ed, I already have your thread on pelican bookmarked for when I get the cutting-board mount ready to go.

On the issue of venting - I noticed that in all the install pics that I've seen with optimas in 911s, nobody seems to bother with this. My gigantic group 91 (?) Interstate has an obvious vent hook-up (though the vent was MIA from the guy I bought my car from). Does anyone actually use a vent kit for their Optima? Does Optima sell one, or would I just use some generic plastic tubing?

I also noted in Optima's FAQ that any drilling of the case voids the warranty. Ed (and others), it looks like the cutting board mount involves drilling holes through the base of the case...has this caused any issue with warranty support for anyone?

Cheers,
Dave

 

The Optima battery is a completely sealed design which prevents loss of water which can lead to plate dry-out and failure.

An Optima spokesman has assured me that the Titanic was not using Optima batteries and Optima was in no way responsible for the ship's sinking.

 

Dave-I suppose they could play hardball on that. But, I only drilled the tab or flange at the base, which in no way compromised the integrity of the body. I suppose it would make it un-saleable as a reconditioned unit.

I will also say that I've never had any issue with the battery. Ruby was down 9 months when I rebuild the motor. The battery was disconnected during most of the time, and a 48 hour trickle charge had her back to full strength. When I updated the motor last year, did the same for 3 months. She sat for probably a month after I got the 993, and fired right up. I'd say it is a reliable battery for a hobby car.

That is the funniest thing I've heard or seen today!

 

well that's reassuring....

 

GB closed

 

I put optima batteries in porsches all day. It is not a big deal. The best one I think is the red top. It is a basic drop in replacement. You might have to play with the mounting alittle but that is it. I dont recommend the yellow top. Not because it is not good but I dont like the warantee. It comes with a 1 yr warrnaty so if it goes bad in 14 months you throw it in the garbage. The red top comes with a 5yr waranty. I have a 911 and 951 and I dont drive them in the winter, except maybe 1 every 2 months and I dont disconnect the battery while it sits and it starts every time. I have had it in for 4 yrs so far...

 

Both the red top and yellow top come with 36 months free replacement, unless in service for commercial use.

http://www.optimabatteries.com/optim...ty/postFeb.php

 

They must have chance the waranty and I am not aware. I will have to talk to my optima guy.
Thanks...

 

They did change the warranty. 2009 the yellow top came with a 1 yr. I guess too many complaints about that. So they changed it to a 3 yr. Good to know. I have been selling them for 10 yrs and thats how many I have to warranty..

 

There is no such thing as a completely sealed lead acid battery, not even the Valve Regulated Lead Acid (VRLA) batteries are completely sealed...thats why they have the word "Valve" in the type description. If the pressure inside the battery exceeds the valve pressure, they will vent. Its also a safety feature/necessity.

And they will vent if overcharged. When will they be overcharged? When you have an incorrectly set voltage regulator, when the voltage regulator does not temperature compensate and even when the latter two are met....when you have a damaged/faulty battery.

VRLA batteries cannot be opened and therefore cannot be topped up. That is their downside. They are also far more sensitive to proper charging method.