Current (no pun intended) Battery Recommendations

My Bosch AGM battery is going on 7 years and is still going strong - mostly. If I let my car sit for a week or two in my unheated detached garage it can be a little weak, but it does start the car. I know that an old battery can be fine one minute and then dead the next. After I installed mine, many people said that the Bosch batteries were no longer any good. What are people recommending these days?

I�ve used NAPA and Interstate AGM batteries for years. Currently have a NAPA Legend in mine now.

I was in BJs today and they had Interstate AGM batteries .

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Original battery in my Boxster was fine for 8 years, no issues at all. On a cold Sunday morning at a track weekend last year it would power up, but not turn starter. Ruined my weekend. Interstate AGM was about $200. Change it.

Ac delco gel 2 years holding up well

My battery started acting in a similar manner where it started the car but with some hesitation. As it got colder it eventually went completely flat. I ended up getting the Duralast Platinum AGM from my local AutoZone and it's been great. If you don't have one, I'd definitely get a portable jump start battery that you can keep in your car. I've been able to jump 3 strangers cars that were stuck with a flat battery on a single charge.

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This is what I'm running. Works great. Even made in Germany. Do your battery tray when installing new battery.

Yeah, good call. I stripped and repainted mine and while at it, cleaned out all the drains. You're already there!

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IF you are open to a Lithium Battery you can look at our Antigravity Battery. It just another option available. Pros- -WIRELESS Built-In Jump STarting so you will never be stranded by a dead battery again. If you over-discharge the Battery, for example leaving lights, or radio or other thing on and come back to a dead battery simply press the provided keyfob, start the car and drive away. You don't have to connect a jump Starter, don't have to open the frunk or ever even see the battery. -2x the power of a Lead/Acid Starter so never a slow of flat start, the motor will spin up super fast - Weighs bout 60% less than a Lead/Acid Battery, wieghs about 13lbs -Ultra long life- 8-10 years lifespan due to offering double the cycles of a Lead/Acid Battery as well has having a full Battery Management protection system in it so you can't damage it by over-discharge, over-charge or other typcial battery issues due to the circuit board inside. - No leaking of any fluids like Acid so it can't ever leak of damage the battery tray. -Drop in fit OEM sized Cons- More expensive than Lead/Acid Batteries. If you want to learn more you can watch this video. You can check them here and see a video on them if this is something you might be interested in. https://antigravitybatteries.com/pro...tive/ag-h6-rs/

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Same. NAPA AGM battery is made by East Penn...solid. Otherwise Duracell from Batteries Plus or Interstate AGM (costco has them also)

Why do not repeat with Bosch? I'm still waiting for a Bosch product letting me down in terms of quality... I'm in my 5th year with my S5 and still not showing any fatigue symptom. You can also go for the S6 if you prefer AGM for a longer life. https://www.boschautoparts.com/p/s5-batteries-s5572b- https://www.boschautoparts.com/p/s6-...attery-s6587b- Plus... they look better in a German car

Went through this about 2 years ago, https://rennlist.com/forums/996-foru...w-battery.html . At the time Diehard, Duralast and Interstate AGM batteries all looked identical. Went with the Duralast. No issues so far.

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I'm very happy with my Bosch battery. The problem is that after I bought mine, many people started reporting problems with theirs after only a year or two. Maybe it was a manufacturing problem or maybe bean-counters got involved.

Interstate. Sold at Firestone stores as well. ~$200.

I would recommend the Varta battery...very good German battery, looks very Porsche OEM and even has the vent tube exactly like the OEM.. It is OEM for Audi... The Moll battery is OEM for Porsche but it is a "Dry stored" battery , meaning it is just a buch of lead plates in a plastic box which gives it a remarkable "shelf life" and when sold it is filled with fresh electrolite and charged to be as fresh as possible but is a PITA when a customer is in a hurry...and is not an AGM.. I talked our Dealership into using the Varta battery instead of the Interstate on Porsche cars after seeing the Moll , Interstate, and Varta all being used in our dealership ...The Varta is much better than the Interstate that was used in Audi's...and the OEM Moll Porsche was about $400 and the OEM Varta Audi was about $200 .. The Varta is distributed in the USA by Interstate Batteries...( on the shelf at parts stores in ROW) .. They are shipped from Germany to Interstate where they are handled and distributed to Audi Dealers each month. They are checked and rotated and charged so they stay fresh with quick turnover... You may have to go to an Audi dealer to get one, or you may be able to sweet talk your local Interstate guy into selling you one . ( but I think they are suppose to only sell/handle them to Audi dealers, but I was able to talk my local Interstae guy into it)...

Circling back just to close my question. I wasn't able to source a Varta battery so I went with the Duralast Platinum AGM L7 battery from Autozone. I think I'm actually a couple inches taller now and also a year or two younger...not to mention the immense horsepower gains.

I just went through a battery replacement on my 2017 C2S and thought i'd share my experience. First off, the car was not exhibiting any issues or slow starts but I tested the battery with a multi-meter and it was reading 12.35 when off which is just under 60% of charge. A 12v battery should read 12.7 or so at 100% charge, and at 12.2 or so it is at 50%. Driving the car the vols were consistently at 14.3 so the charging system was working fine, but the Battey was tired. Car went into service in May of 2018 so it was 5 years which is about the limit in the Florida heat. When a battery gets this low you are essentially over-taxing your alternator as the demand is greater on the charging system and the alternator will fail prematurely. I learned this the hard way on my Toyota truck years ago by running the battery for 7 years- and the battery never showed any sign of weakness until one day it died. and so did the alternator. Imagining that Porsche alternators are more expensive I opted to have my battery replaced. The dealer was at $1450 for OEM AGM replacement and my indy shop was $450 for Interstate AGM equivalent. There is in fact some programming so that the car knows the battery is new, as the charging system will adjust to the age of the battery as well as the specs. Yes, you can swap out the battery in your driveway and it will fire and run but the charging system will not be 100% efficient as it should and may shorten the life of the new battery. As a DIY'r with a lift it pains me to take my 911 in to the shop for anything but I didn't want to get this wrong on such a computer controlled car! Lastly the shop's advice was no tender is needed unless the car doesn't get driver for weeks at a time, or if your drives are frequently only a few miles when you do drive it. Also, always lock the car, even in your garage as when the car is left unlocked it is in a "ready" state and certain systems are on as it anticipates the car will be started at any moment. I hadn't done this for the last year but now am locking the car in the garage so all systems "go to sleep" when parked.

I replaced the original Banner H7, AGM type, 80 Ah battery, Porsche Original Telle [Part No.] 999.611.080.12 in my 2017 C2S today with one purchased from a local Walmart store. The new battery is same H7 size, also AGM type, 850 CCA. I'm trying to code the new battery to my car using an iCarsoft POR 3.0 scan tool which is advertised to be able to do battery registration. Per the iCarsoft protocol, it first requires entry of the Ah size, then the type, then a Product Code and then a Serial Number. Each number or character has to be entered one slow step at a time; there is no touch screen on the iCarsoft POR 3.0, and if you make a mistake, you only learn that after you have entered what you think should be entered and click on the enter command button. And if you're wrong per the iCarsoft tool, it tells you to try again and you have to start over from the beginning. My problem at this stage of trying to register the new battery is that Walmart doesn't provide a product code that the car will accept. Walmart has their internal product code for inventory purposes but that doesn't work. Apparently the correct product codes are alpha-numeric. I have a Serial Number which is to be entered after the Product Code because that appears clearly so named in a sticker on the battery, in my case Serial Nr. is JCH20094498946. The battery was manufactured in September 2023 and cost $180 plus tax plus a $12 core charge that is to be refunded upon return of the old battery. Where can I get a battery Product Code to use for an 80 Ah AGM battery, ideally for one made by Johnson Controls [VARTA?]? I tried the Porsche Part Nr. and the old Banner battery code and neither worked. I also realize that entry of this data via the iCarsoft scan tool requires exactly the correct information in the correct format, including any blank spaces. [I've been through this earlier this year in two different Audi cars model year 2011 and 2013, and each of them had a different size and type of battery and each required different coding information that was performed using different scan tools, mainly an AutoPhix 7610, although I also have an older Foxwell NT500 which came very close to working for battery registration but ultimately failed, probably due to the scan tool needing to be updated and Foxwell refusing to offer updates except upon further payment. I found I could buy an entirely new scan tool from either Foxwell or many others for less money so I quit trying Foxwell.] Is there anyone on the Rennlist forum who actually understands what these battery codes are, and what the BMS [Battery Management System] actually does on a 991.2 Porsche Carrera 2S, and what happens if the new battery is not registered? I've spent far more time trying to obtain the information needed to update the BMS and again trying to enter it via the iCarsoft scan tool than I did changing the battery and thoroughly cleaning the items that became accessible when the old battery was removed. I've also read many posts in multiple threads and it seems that no one has definitively had adequate, accurate knowledge to know exactly how these systems work and whether or not registration of a new battery is truly needed or not or whether the new battery will not be charged properly or will be overcharged or undercharged, etc. This is surprising because in most other technical areas, there are truly impressive and detailed authoritative descriptions posted by knowledgeable participants on Rennlist. One additional point: I used a genuine Porsche branded [CTEK manufactured product] battery maintenance charger which I connected using the center console cigarette lighter socket before changing the battery; it's supposed to be able to supply about 4A at the requisite DC voltage. I carefully removed each battery cable and covered the exposed end using an 8-mil rubber glove. After I reconnected the new battery and went into my car, I noticed that the dash clock time was incorrect. I corrected itself in less than a half hour, but that tells me that the Porsche battery maintenance charger did not maintain adequate voltage throughout the process as did my CTEK 7002 charger that I used when changing the Audi batteries, after which I lost nothing in my settings in those Audi cars.

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wow. Do I have to do this kind of thing to register a battery anytime I disconnect my battery and the car needs to relearn settings? Please tell me my 996 is old enough to be immune to this stuff.

Nah. Sounds like a 991 issue with all of the electronic bells and whistles getting in the way. Glad I have a 996.

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It is. But I just went through the process on a BMW and didn't find it to be all that intimidating. It did ask for serial number but it also let me skip that part. My tool even reset the time and date for me which I thought was very nice of it.

I have no knowledge of the 996 chassis electronics. As other posts have noted, the 991 chassis platform has much more electronics systems and computer code. It also appears that people who use a higher level [and price] scan tool are much more likely to be successful in registering a new battery. The good news in my case with my 2017 C2S is that despite the clock displaying the wrong time after the battery swap with the Porsche battery tender connected throughout the swap process, I did not lose any other settings. The PCM appears to be functioning normally as well as the MFD display screen.