Erik N

I know this has been discussed before... What is the best battery for the 928? Would someone please post a link? Thanks in advance!

No HTwo O

Interstate would be a good choice. Other guys go to Wal Mart and AutoZone.

I have the MTP-91 in my Turbo.

http://www.interstatebatteries.com/c...349-2147384906

dr bob

I've had mediocre results with the Autozone "Duralast" and "Duralast Gold" batteries. Without risking a libel action, I'll just say that I would recommend that you continue shopping elsewhere.

m750rider

A Walmart battery is working well for me.

Fogey1

Recent 4 page thread. "Which battery to buy?" Lot of info & opinion.

https://rennlist.com/forums/928-foru...ry-to-buy.html

IXLR8

Or for any car. One that lasts and one that fits right.

This is not what you've asked for, but after reading so many battery threads, I have to at some of the advice one finds on them.

I'm amazed that many think 4 or 5 years is considered good life out of a battery. My last OEM battery lasted 18 years (last I heard after selling the car when it was 16 years old) and the OEM battery in my present car is now in its 13th year. They were/are both made by Panasonic and came with the cars; unfortunately not available on this continent. I have an East Penn group 48 battery in the 993.

What kills batteries? Improper charging (under or overcharging), both on the vehicle and while stored, heat, and vibration.

I have a cockpit mounted digital voltmeter connected directly to the battery to tell me what my alternator/voltage regulator is doing. During the off season, I can tell if my maintainer is charging the battery properly. Many chargers do not charge a battery correctly based on battery type and battery temperature.

Heat reduces battery life substantially. A battery in AZ will not last as long as one in WA.

Vibration is a killer as well, which is why they should be fastened down. I install my batteries on a closed cell foam mat or battery mat as well.

AGM batteries such as the Odyssey, Optima and others like it (or GEL) are not what they are cracked up to be. They have their advantages; they also have a lot of disadvantages. I only use flooded lead acid (FLA) batteries that can be user maintained which is why my batteries last.

jheis

Hey Erik:

Regardless of what it says on the label, virtually all of the car batteries sold in the US are made by one of three manufacturers: Johnson Controls (which supplies roughly half the market), Exide, and East Penn. You can get the breakdown by brand from Consumer's Reports.

Buy one that fits made by Johnson Controls - such as Interstate or Kirkland (Costco).

Keep the green side up....

James

IXLR8

I wonder if the East Penn battery I bought is actually made by them. Other than the case color, it is 100% identical to the Moll-Kamina Porsche battery that came in the car.

BTW, there is also Enersys with countless brand names under them.

jheis

Hard to tell. Battery manufacturing seems to be a particularly incestuous business.

For example, the "Die Hard" brand is associated with Sears. But Sears is a retailer - Sears doesn't "make" anything - they sell batteries made for them by the big manufacturers. Most, but not all, of the Die Hard batteries are made by Johnson Controls.

Kinda like Craftsman Tools - good stuff, but Sears doesn't make tools. Craftsman tools (at least the good stuff) are made by Danaher Corp - which also makes many other brands you've probably heard of.

James

Erik N

That is what I needed! I was considering an Optima, but after reading that thread I think I will go with just a regular battery.



I think I will compare a Walmart battery with a Sam's club battery, and maybe Autozone/Napa.

The other thread talks about the 928's battery hold-down attachment. My '78 has nothing like that, just a snug fit in the well, and a bolt-on metal lid. I put a piece of foam over the + terminal to avoid grounding out if the green side ever goes over.

Of course, there is no factory spare hold-down, either.

Thanks everyone!

heinrich

I'll put my hat in the ring here to say Optimas don't fit and in fact are no better than any other. When they die, they die suddenly.

Best battery is one you don't let drain. Ever.

Alan

I'd say the best battery is one that fits properly, is a reasonable deal with a great pro-rated warranty from a place that will have an outlet fairly nearby - wherever you are - when the battery dies...

Alan

danglerb

Speaking of prorated, I was thinking about that the other day. As I understand it with the Duralast Gold from Autozone its 3 yrs free replacement, and 7 yrs total prorated.

At 35 months I get a new battery, but the warranty is from the original, so 1 month free, 49 months prorated from original purchase date.

At 37 months I can buy a new battery for 37/84 reg price, but get a new full warranty.

If a battery is $100, where am I costwise after the second battery dies?

First case, $100, next one free, third 70/84 x $100 = $83, total $183 with new warranty, or easy option to switch brands etc.

Second case, $100, next one $43, third could be free or 2 months later another $43, so $143 with little warranty, or $186 with a full warranty.

Waiting until the free replacement is over if your close may be a better option even though you pay, you get a new warranty.

*** Keep your battery and tire purchase receipts in the car.

redpathtribe

Erik, go with the Walmart battery, you'll get the best price (vs. Sam's, Autozone, etc.) and it fits Alan's criteria above well too!

namasgt

I have a Optima battery from the previous owner, but it doesn't fit properly. Roger always buys his batteries from Porsche, I cant remember what brand they are, you should ask. Or maybe he will chim in with his experience.
You should avoid those cheap batteries like "value craft" sold in Autozone. I went through 5 of them in my last car before I changed to Duralast.