heinrich

I'm not sure how you guys do it. It's a fact that the red tops (I own one) at least the ones that were available until a couple of years ago, have their positive post so far in on the battery that the 928 positive post does not reach. I've been driving with one in Godzilla and the battery is suspended by the positive post. I don't have any height clearance issues. It sounds to me as if we are talking about two different batteries?

Slantnose!

Yeah, I think they did freshen them up a few years ago.
For example, I couldn't fit a 'yellow top' in because of the posts being positioned to far towards the center.
The older 'red tops' used to be exactly the same, but now they look different and also have the terminals off to the side much more.

dr bob

I'm note sure of the reason one would think an Optima is better in the 928. The Autozone battery was ~$60, five year projected-by-me life on a seven-year warranty. The cheapest Optima red-top, at Costco, is about twice that cost. The big killer of batteries for most owners is lights left on, extended drain during storage, and other abuse. I guess I'd rather cry over killing an Autozone battery, knowing I can drop by the store and get another easily, as opposed to getting third-party warranty replacement of a Costco-purchased Optima. If nothing else, I can put that 'extra' $60-100 to work for seven years and double it a couple times while my car still starts and runs fine. Time plus $ equals $$.

Slantnose!

Well, for me being a 914 owner for 25+ years...
Anytime I can avoid that stuff spilling out is enough reason for me.

69gaugeman

had a 73 2.0. Anyone who puts the EFI computer connection below the battery should be shot. (this was in the seventies so they only knew about leaky batteries).

Big Dave

I can get a new Optima red top for the same price as the Autozone battery.

Now you guys have confused me....so newer Optima red top batteries have the posts in a different location, requiring only the ground strap to be longer??

Slantnose!

Yes, new 'Red Top' will work fine.
(the + cable is just barely long enough & you might need to protect the top posts from touching the door)

SeanR

I have no length issues at all.

Alan

I agree with Dr Bob - I see no reason to change from the stock Group 48 BCI type battery (later cars). The Interstates or Exides for example are relatively inexpensive for a big battery - match the stock specs - last fairly well, have good & easily claimed prorated warranties & are physically identical to the stock Porsche battery - except that many are also vented - so if you actually do vent them properly the chances of a spill are virtually eliminated.

Being the exact stock footprint means they bolt down solid as a rock with no adaptation required...

It seems like a lot of risk & effort from a fitment point of view - I've got other bigger fish to fry (...or is that catch?)

Now a seperate back-up battery would have some utility - especially in Phoenix where the heat kills all batteries faster than normal... Humm!

Alan

69gaugeman

If you are going to switch, why don't you replace the ends and use the side terminals?

Iris and Kevin

That's true we could have chosen side terminals, but we didn't know it would be a problem when I bought so we got the same top terminal as what was in the car.

dr bob

The side terminal gives you a sealed/o-ringed "joint", but the surface area for connection/contact is smaller. IMO, the posts are a better bet. Seal the connection with Vaseline after it's all done mechanically, install/connect a vent tube to steer the corrosive vapors outside the battery box, and you are good to go. I looked hard at side terminbals and cables for anotehr performance application and they came up short. What they are good for is powering accessories like audio amps and the like. Run the starter and engine from the post in the original configuration, and have the side terminals available for all the "extra" wires needed for the aftermarket stuff. They both run the same battery down though.


I came up with an extrs pair of 18AH gelled-electrolyte batteries that might find their way into the car somehow. Charge through a big diode, and maybe use them to run the TE cooler like Carl did. A ---relay--- could be used to let this battery assist on hard starting, kinda like those starter-booster vbattery gizmos do. Just another relay-- who would know?

SeanR

The reason I decided to get the Optima Red instead of putting in another generic was from past exp with batteries. I used Optimas (2 of the blue tops) in my boat, running 3800 watts of stereo and all the accessories that came with putting a boat on the water. Yes, this is a different scene than with the P-car, Blues are the deep cycle, but with the drain and loads that I put them under on the lake, and they always jumped back up to 100%, I felt really safe with one in the 928. Is it needed? Not really. Do I prefer it? Most definatly.

On this car, the PO had not figured out why there was such a bad drain, didn't trouble shoot it and ended up killing an Optima Red. The 1st day I had the car I found out what the drain was but it took me a month to trace down a starting problem (I assumed there were other drains but it ended up being that the PO killed the bat) I got the car with a bad battery, but since I had such High expectations of the Reds, I figured that was not the problem and put another one in there.

Optima's can go bad, as with any battery. Hell, in the Lexus and my truck, they run standard walmart crap with lifetime warrantee's, but I wanted the best power, best cranking and a non acid bat in my P-car. So I chose what I found was the best one around. Cost wise it is high but I will put another one in there when this red one craps out on me. Besides, I have a larger stereo in mine with more amps in the future, I think it is a win win situation.

Franks928s

I faled to find the red top battery on the interstate site using the product numbers in the thread. can someone tell me what product number to use? Also, a few additional questions:

my car is a 87 928s4

1) will I need to extend the positive cable if i get the red top reversed terminals battery?

2) Does the Optima require any type of venting or hold-down?

Thanks!
Frank

Mike B

Here is a new thread offering Optima batterys at a bargain price...$115!

https://rennlist.com/forums/for-sale...y-grp-buy.html