Dual Battery Options

[merbesfield]

I wanted to post an update to my post from 12/16/13. There seems to be some confusion on the exact batteries sold by AutoZone and Advance, which they sell under the same part number as 8AMU1R. When I received the battery from Advance, it was not a sealed battery. I then went to the AutoZone store around the corner and in fact their battery also was not sealed. WTH! I check by tilting the batteries and they leaked. Not good. So to be clear, not all batteries sold under the part no. 8AMU1R are sealed. Of course no one at these so called parts stores was able to help, I did not even try to ask questions. I then went to my Deka/East Penn wholesale warehouse to get the exact battery I have ordered before, which I should have done from the start. The battery they sell under the part no. 8AMU1R is definitely a sealed battery, which can be turned on its side etc. According to the Deka sales guy, all batteries have some sort of vent, but the sealed batteries will not leak out the vent when turned on their side. Deka sells/manufacture numerous AGM sealed batteries and they are relabeled. I saw several different stickers, Duracell, Batteries Plus, etc. I bought a Harley Davidson sealed AGM off the blem shelf for only $36.00 and the guy through in some threaded posts. We did a battery test on it and the 8AMU1R side by side and the HD battery was even stronger than the 8AMU1R. He began to explain why, but by this point I was on battery learning overload and did not care to listen. I will try to post a pic once it is installed in the car.

[speedo]

So I called the local Batteries Plus and an overly anxious sales guy said he knew all about the SLI70 and would check availability and call me back...didn't happen. I stopped by several days later and spoke to same high strung guy who said he didn't remember the conversation. Found out why...SLI70 is no longer available. Said they migrated to the SLI75 which is dimensionally bigger. I asked how hard it would be to check their wharehouses and find a stray SLI70. He didn't see that as being productive and instead wanted to point me in the direction of an Oddessy 925. I have a 680 in my race car and it is adequate...not great (meaning it has starnded me before), but acceptable. Anybody have experience with a 925? I like the idea of the posts being on the front.

Speedo

[Jim Breazeale]

Nobody has mentioned that Interstate has the dimensionally correct, sealed battery for dual battery 911s. It carries a specific part number. We carry them. Most Interstate dealers don't know they exist. No, we won't ship them.

Regards

Jim

[BrentF]

A pair of Interstates is what i have. The alternative proposed by Justacoupe of the Duracells with side posts is a great alternative, given the ease of access to the battery terminals. I consider Porsche's layout of the batteries to be a very poor design, especially if you need to give the car a battery boost. This side posts resolve this problem provided the positive terminal can be reliably shielded.

[Jim Breazeale]

A pair of Interstates is what i have. The alternative proposed by Justacoupe of the Duracells with side posts is a great alternative, given the ease of access to the battery terminals. I consider Porsche's layout of the batteries to be a very poor design, especially if you need to give the car a battery boost. This side posts resolve this problem provided the positive terminal can be reliably shielded.

I have to differ. I am not a fan of the side posts at all. Porsche's original design is a bit quirky but works very well and the battery terminals are well protected if the original rubber caps are present. The side posts expose the positive terminal to possible contact with items in the trunk. The worst part of the dual batteries was the fact that they are not convenient to check as often as they should have been, which led to early battery failure. The current sealed batteries eliminate that problem. That said, I have a single AGM (Optima) battery in my own 71 911.

Regards

Jim

[NorthernThrux]

I recently bought two Porsche batteries for the early cars (part # 999.611.014.91) for C$448 out the door. Yes, that's insane, but then so is the fact that my car is worth considerably more than my first house.

My logic being that if and when the batteries give up their ghost, I'll cut open the cases, but a more compact AGM (e.g. Miata) battery in them and then seal them back up. Keep the original look and avoid packaging problems.

[merbesfield]

Lars, I stopped by one the local Batteries Plus and they had a few choices that would work for you similar to the "over priced" Oddessy IMO. I guess your store wanted to sell what they knew, or did not know. After all the research I have done, which is way too much, I thill think the best battery is the one referred to as the Mazda Miata battery, which they also sell. Branded as a Duracell battery, produced but East Penn. Cost just under $100.00. Rated at 330 CCA, but likely higher when tested. It does have vents, which are for off gassing, but not liquid. I tested it and nothing came out. I am still perplexed as to why one of the Miata batteries sold by AutoZone had a drop of liquid come out when I tipped it, but maybe that was a fluke. These batteries are labeled as non-spillable and are AGM. If you want one of the smaller motorcycle style AGM's they sold those as well, but less power and more money.

http://www.batteriesplus.com/product...6L-320CCA.aspx

Edit: I will never buy an Optima battery. I have only bought one, a red top, for my DD truck, and it has died on several occasions and has been replaced once as well. It still dies very fast if anything is left on by mistake. Very unimpressed and after all my research very overpriced for what you get. It is all about the marketing!

[mac73s]

Jim - would you please provide the Interstate part number? Thanks!

Nobody has mentioned that Interstate has the dimensionally correct, sealed battery for dual battery 911s. It carries a specific part number. We carry them. Most Interstate dealers don't know they exist. No, we won't ship them.

Regards

Jim

[jrbennett]

The current Interstate part number is 911, I believe it used to be U911-50.

http://www.interstatebatteries.com/c...d+Battery_All)

I tried to buy a pair recently, however my local Interstate dealer says USA only, they are no longer available in Canada.
I ended up buying a pair of batteries from Porsche.

Another option is the Sonnenshcien A512-40 A, I sourced them out locally but they were nearly $60 ea more than the Porsche battery.

http://www.sonnenschein.org/A500.htm
http://www.sonnenschein.org/images/A...%20Porsche.jpg

[Longballa]

I bought the U911's from Marco when my ST was there and it's been a year now and they've been great. Never charged them or done anything to them. Fit great, look great and I never worry about them not cranking over the 3.2SS.