RennListUser01

Ya know, after some initial negative consideration, this might just be the right thing to do - I mean, more than just based on initial low cost of the FLA batteries - or even of an AGM.

Some estimates range as high as 5X the life of an FLA (AGM probably a bit longer lasting than FLA) - if so, this may be better for the initial owner, and even future owners.

Are there any downsides other than initial cost?

straka

I tested my Porsche OEM 800 amp AGM Battery and at 5 years it had a high internal resistance of 6.43 mili ohms and was down to 356 amps. Time to get rid of it before it let me down. Other indications were Auto Stop Start quit working (when I forgot to shut it off) and the coasting feature wasn't available.

IXLR8

Just wondering who told you that. I highly doubt it, because I got 14 and 16 years from my last two everyday lead acid batteries I had in my cars that I owned that long.

They were given no special care other than a slight topping up every two years and neither of them were ever on a maintainer. Yup, that is old tech for you.

I don't see the financial point but people are free to spend money as they see fit.

F1SML8R

I personally am a big fan of the AntiGravity product. OEM drop-in fit, finish and quality. Also the restart button and additional monitoring app is just a big plus. It's the easiest way to lose 30+ lbs. depending on the option you go with in the best spot (i.e., higher center of the car location). So you not only get weight loss, you actually improve the center of gravity as well. Win, win, sans the cost compared to the lead acid anchor that is all other (and cheaper) lead acid options.

Porsche_nuts

Such as?

IXLR8

Not that it makes much of a measureable difference, why would I want to get a higher rearward bias with a lighter battery? The 911 is tailheavy as it stands.

Plus any H6, H7 or H8 battery is a drop-in replacement.

For the price of some fancy smancy battery, I can easily buy 3 AGMs. In the past I got 14+ years out of a standard FLA battery; the factory AGMs I have now in my 991 and BMW motorcycles are at 7+ and 6 years and start them both like day-one.

I can never understand the paranoia of battery failure. In my 48 years of vehicle ownership, I might have needed 2 boosts.

may010

Has anyone tried putting in one of the Odyssey Performance batteries from FCP Euro on their 991 (like this one)? If so, what were your thoughts on it?

981KMAN

I have used Odyssey batteries in the past with good results. I would go with their H6 battery if you have a Coupe, or their H7 Battery if you have a Cab or Targa. I'm just not a fan of oversizing the already heavy battery. Yet in any case, Odyssey makes a very good battery.

vincenz0

Found this thread searching since my 991.1 battery is on it's way out (seats will no longer adjust unless the car is running and other weird electrical things, but it still starts everytime and I drive it daily). Huge fan of Interstate and have been putting them in cars since I was 16. Never had an issue with one.

But the one you guys are installing (and is recommended for our cars on the Interstate website) is a freaking behemoth -- the MTX-49/H8. It's much longer and 11+ lbs heavier than the OEM battery.

Someone in the thread mentioned this one which is comparable in size and weight to the OEM Porsche battery - MTX-48/H6. It only has 760 CCA instead of 900 but it's still AGM and I'm sure that is plenty of juice. I'm going to give that one a go.

981KMAN

I agree.... the H6 is the battery size that came in the car from the factory, and has the required capacity. I never really understood why folks keep upsizing their battery for no reason, and carry around the extra weight. If your car is a Cab or Targa, then you probably received an H7 sized battery from the factory due to the Top Mechanism requirement, so replace with an H7 sized AGM battery. No need for the huge H8 sized battery, its just a waste.

Antigravity

The Porsche 911 Cars, as well as most all other Porsches have the ability to accept H6, H7 , H8 sizes. Some of the varients with all the extra accessories such as heated seats and such are spec'd with the H8 simply because it has high Amp Hours, which mean more energy storage Capacity. But in general that is not needed unless you are driving in extreme cold weather, don't drive often and desire a longer storage time, or have added additional aftermarket electrical accessories being the higher capactiy will cover more of a parasitic drain.

So the Porsche Battery Tray has a Cleat that is adjustable to fit any of those 3 models listed above. You just move it over one space for the higher number battery. H6 is the first threaded hole, H7 the second threaded hole, and H8 the third threaded hole. All the H Series batteries are the exact same Hieght and Depth, but vary in the Left to Right Length by 1.5"inches longer. So H7 is 1.5" longer than H6.... H8 is 1.5"inches longer than H7. But they all drop in to Porsches just fine. So you are just buying for the Amp Hours available with H8 being the highest, H6 being the lowest. H6 does perform absolutely fine in most circumstances, but again higher Ah does benefit some. And as you get bigger, you do get quite a bit more weight. The H8 is quite heavy for sure.

IXLR8

Well the factory installed Banner battery in my 2015 is a 800 A, PN 999.611.080.12 and it is a H7 size aka 94R. Just starting its 9th year of service.

Does Interstate actually manufacture batteries or are they made by JC or East Penn?

Antigravity

Being blunt you will not be finding your 9 year batteries or 14 year batteries that you state you have in your vehicles anymore. There have been dramatic changes in manufacturing Lead/Acid batteries so that the batteries are not even intended to last more than 4 years in recent times. This is simply because it is a recurring revenue stream for the corporations so they build-in obsolecense nowadays.

You can prove this out simply by doing a search on Batteries on Rennlist and literally hundreds of threads come up with batteries going dead, or flat or causing flags. Its one of the main issues reported on this forums and many others. This is not to say that its all the batteries fault, many people are missing maintianing them of have high parasitic drains, but there is a massive number of posts proclaiming the batteries are just not lasting in the first place...and that is across all the forums, and comments we see at Tradeshows and also a fact known in the battery industry. So you are indeed one of the outliers when stating you are getting 9 year to 14 years out of a battery, so keep doing what you are doing, but it's not happening for the many others.

barncobob

dont be be doing out of town road trips..

IXLR8

Its not happening for many of them for various reasons.

And I don't buy the rest of what you mentioned. There are quality battery brands and others probably manufactured to a price point for companies that put their own name on them.

I'll be installing an East Penn AGM when my 991 battery packs it in. I'll let you know when it quits. Mind you, it had a previous owner for the first three years.

No stake in my past experiences. After all, I'm not selling batteries.

By the way, you missed the 16 year old battery. And both the 14 and 16 were low tech floodedl lead acid batteries made by Panasonic. Can't get them in the aftermarket, but I do use their NiMH cells.