Stevarino

UPDATED POST (Jan 2005):

Unfortunately I found myself in the need of a new battery again last week. My 993 mostly sits and suffers from very short trips when it is driven. Luckily I had seen the Optima battery posts by my Rennlist brethren and an Optima wholesaler is located in Santa Monica - Advanced Battery Systems, 310.450.1630, www.absbattery.com, NO affiliation, 'just very grateful they were open New Year's eve and provided great service AGAIN:

There are now two Optima batteries that fit very well and are an easy installation:the battery model D35 (Yellow Top) (more information at http://www.optimabatteries.com/publi...eep_cycle.html)
and 75/35 (Red Top), part no. 8022-091 (more information at <http://www.optimabatteries.com/publi...e/starter.html ). Both are available from Advanced Battery Systems (ask for Richard Klein "richard@absbattery.com" or batterymart.com, etc....) Unfortunately, the curved positive battery terminal found on our 993s makes for difficult fitment on any inboard battery terminal, as Yellow Top owners can attest, so I returned the recommended model 34/78. Note that on the D35 that it is available without the side post mounts and provides a bit more room for removal of the spare tire.

Here's how I installed the 75/35 and the D35:

- Remove boot liner, spare tire and plastic bulkhead for easy access to battery.

- Remove old battery

- Clean/repair acid damage - not easy due to CD cassette and what I believe to be the ABS brain box. Good earlier post by Mike Cap on two products for this: ACF-50 13oz spray is p/n 09-44350 excellent anti-corrosion spray that is used in the aircraft industry for spraying inside wings (they "mist" it) and fuselage areas and a particular paint by Randolph specifically for battery compartments called "Acid Proof Black" p/n 344QT available from <a href="http://www.aircraftspruce.com." target="_blank">www.aircraftspruce.com.</a> Their phone number is 800-477-7823. I intend to order these products and further tidy up the boot when I have more time.

- Remove the battery drainage tube and plug hole. Now is also a good time to replace those ageing drain gaskets available for $3.50 per. You may also want to hardwire a trickle charger and run the wire into the driver's side headlight cavity. More on this later.

- Turn the battery so that the positive terminal is towards the front of the car and the negative is to the rear, but before sliding the battery against the inside fender rail, attach the positive battery cable and then the negative cable.

- Slide the battery against the inside fender rail and bolt into place. I found tapping the base of the battery towards the inner battery rail helped to snug it to ensure proper fit.

Finished.

As to the hardwire receptacle that sits inside of the driver's side headlight binacle, I'll post instructions and photos if folks have an interest.

My thanks to Anir, Mike et. al for the many helpful posts on this subject.

Stevarino

Photos of trickle charger installation:

chris walrod

Thanks for sharing this info. My batt is original and prolly due. They all seem to priced at $110.

aof

Great post- I'm sorry, it came too late for my acid spill surgery

Here;s what I did; thoroughly washed the floor pan with baking soda paste. Then sand papered, followed by a generic anti-rust liquid from Nappa. Then sprayed with a primer.

I hope it holds!

Optima red top in the spring.

JohnJL

thanks Stephen, I've got a spare out of my FJ dual setup (switched to 2 Optima Yellow Tops) that goes in soon...

Thanks for the writup and pics!

914und993

I don't get it. Why do you want the trickle charger hardwire to go into the headlight bucket?

Chip

Stevarino

I don't like to leave my car unlocked in the garage when I travel.

914und993

Do you remove the headlight to get to the plug?

You can still lock your car with the front lid up if you push the lid locking latch into the down position. Car thinks everything is shut, and all lights go off.

This is safer for me, since with the lid up I'm not likely to forget the maintainer is hooked up and drive off without unplugging.

Chip

Anir

Hi Steve,

Thank you for the helpful post. I just installed a Red top last week, to replace the Orange top originally installed 4 years ago.

Stevarino

My pleasure guys. This is about as ambitious as I get with servicing my car. I would strongly encourage anyone who doesn't use their car regularly to use the trickle charger, especially on the red top.

grmnxtc

But wouldn't anyone who knows about Porsche's just pull on the emergency release cable (seen quite visibly in your photo!) pop the lid and still get into the "trunk"?

Just a thought....

Clive.

Stevarino

Sure, and then they would activate the alarm..... Which is of course why I installed it this way.

flyenby

Have been told that the Red Top is the one to use, as the yellow top is to hard on the charging system, being such a deep cycle. I run a red top and a Sears maintainer and have had no problems, just what works for me. Also have heard DO NOT try to re charge a red or yellow with the cars charging system as it will damage the alternator

914und993

The potential problem with AGM batteries like the Optima batteries is that because of very low internal resistance, they accept charging at a very high amperage rate. This will force the alternator to output much higher amperage at the start of charging of a partially depleted battery, though it will recharge much more quickly than a standard lead acid battery. The higher alternator output equates to higher alternator temperatures and probably shortened (by how much?) service life. That is probably a pretty good reason not to ask the car's charging system to recharge a seriously depleted Optima battery - use a plug-in charger instead.

I have an Optima in my 993, and partially for this reason I keep it on a battery maintainer - so the alternator isn't called on to work hard recharging the battery after the car has been unused for a period of time.

Chip

solsrch

I'm a little lost on the maintainer too. I've got the standard issue Porsche maintainer, purchased on eBay. I plug it in the lighter, then close the door and lock the car. It is tight as a drum.