New 996 Battery Advice

DISCLOSURE: ALSO POSTED TO PELICAN / DUPLICATE POST, NEED HELP Howdy, Long time since last post. I need to change out my 2003 C4S battery, and looking both online and in the forums unfortunately only has me confused, and the original owner�s manual and paperwork, all of which I still have is absolutely useless on this one. It quotes lightbulb sizes, but not battery size. The old battery is an Interstate Group Size 91, with a vent tube. The internet claims that the 996 can handle Group Sizes 90, 91 or 92, which are equal to Sizes 47, 48, 49, respectively. From what I see, the difference in size, from smallest to largest, means more cold charge applied. The internet also claims that my battery can be �updated� to a sealed (tubeless) battery, or a top-of-the-line AGM, if I want to pay. So, here�s the question(s): 1. Does size matter? Should I stick with the 91, or upgrade to what most car part stores are recommending (a 94R is what Napa and AutoZone recommend). 2. Do I need the vent tube? Can I upgrade to a sealed battery instead? 3. Is there a �best� or �right� answer to, �what battery belongs in my 996?� If I had to guess, a sealed Group Size 48 / 91 would be just fine. Yes? Thanks a ton, Peter

I went with a 48 a few weeks ago, not at all concerned with winter starting, it will be stored during the winter. As a side note, there was a thread a few weeks ago (right after I bought mine from NAPA) that stated the batteries are made by maybe 2 manufacturers now, much research to do now, if your interested in saving a dollar or two. Greg.

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Thank you very much; appreciated. Assume the battery was tube-less and sealed?

I installed a Duralast H6 AGM battery from AutoZone (they are located within walking distance from my house). Works great, no off-gassing (so no vent tube), great cranking power (amps). Well worth the money. I had my battery tray refinished at a local metal shop. Came out perfect. Even has a sticker on the battery "Made in Germany". Go figure....

That is a gorgeous battery tray . And you took that photo of your battery...while on the roof? I ask only because you’d have to be upside-down in my car to have the terminals oriented that way!

Go for the H6. Almost 10 lbs lighter than the next size up.

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Take picture, load on computer, rotate pic and save.

I also went with an H6 from Autozone. Cranks faster than the one I replaced which was also an H6 but since my car is 4 years since I bought her I changed the battery as a maintenance item.

Go AntiGravity H6 and lose even more weight! It also solves the problem of your battery goes dead on you.

I recently bought an H7 from Autozone. It was what they had in stock. I wish Autozone was within walking distance! No �made in Germany� sticker.

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Wow, you guys are much stronger than I am. Walking distance doesn�t mean you carried that battery home, right? Lol For my car, I use almost no power, so even the smallest battery would work. I�m hoping the antigravity goes on sale beyond 15 or 25% off at some point, so I can grab one and drop 30lbs of weight.

Pull old battery, bungy cord to my dolly, walk to AutoZone. Turn in old battery, get new battery, bungy to the dolly and walk home. Yes, way to heavy to carry. The "Made in Germany" sticker is upside down in this photo, but you get the idea. The 760 cold cranking amps and 950 cranking amps is stunningly good.

Carry old battery to the minivan. Drive 4 miles to Autozone. Carry battery inside. Stand in line with battery for 45 minutes waiting to be helped. Carry new battery to minivan. Drive 4 miles home. Carry battery to my 996. Install battery.

Hey Peter..just north of Philly myself. There is no right or wrong. Factory has a huge battery that can start after being left 1-2 months without starting. Depending on your need you can replace with same. You can go smaller/lighter if weight is your concern. If you want max weight saving and spend a grand or so you can get a 5 lb lithium battery. If you want something in between, you can go AGM that'll be somewhere in the middle weight wise and cost would be somewhat similar to a factory size one. There is too many choices depending on what you want.

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Peter here is some answers to your questions 1. Does size matter? Should I stick with the 91, or upgrade to what most car part stores are recommending (a 94R is what Napa and AutoZone recommend). Forget about the sizes called the Group 90 or 91, 92 if you are in the USA. These sizes are rarely called out or put on Battery Labels anymore. As you said they are called Group 48 , Group 49, and Group 94r. But now they are even being called more so by the Euro names of H6, H7, H8. So if you look for those batteries names you will find them readily available everywhere. 2. Do I need the vent tube? Can I upgrade to a sealed battery instead? No and in fact you should get an AGM battery... a little more expensive but they will not have the potential to leak the acid out of the battery and can save you from a damaged battery tray and rusting. 3. Is there a �best� or �right� answer to, �what battery belongs in my 996?� There is NO right answer here. Please note ALL those batteries H6 (group 48) , H7 (Group 94r), or H8 (Group 49) will ALL fit in your 911 as well as most 911s since the 1980s. I say they ALL fit since you have 3 different threaded holes in your battery tray to accommodate each of those sizes, you simply move the mounting cleat over to fit the size of battery you have installed, its super easy. If I had to guess, a sealed Group Size 48 / 91 would be just fine. Yes? Yes this would fit perfectly fine and it the smallest of the three options. The only reeasons you might want to go larger are if you DESIRE more battery capacity... meaning a BIGGER battery with more Amp Hours. Amp Hours are the capacity of how much energy is stored within the battery. That can be more benificial if you drive in below freezing weather often, or if you have more accessories on your car such a cameras, radar detectors, aftermarket theft alarms, or a larger stereo that is much bigger. Otherwise the Group48/H6 is perfectly fine. If you are ever looking at Lithium Batteries that is what we do. Its a high power lightweight battery and they have built-in Jump Starting so you can never have a dead batttery or be stuck with a dead battery since it has a back up reserve inside. It also has a much longer lifespan, but they are more expensive.

My C4S had this Bosh installed when I purchased it (2 years ago) and no problems so far https://www.boschautoparts.com/es/au...?partId=S5572B You can upgrade to the S6 version too https://www.boschautoparts.com/es/au...?partId=S6587B

Long story short I bought this agm for my generator in 2019 and then had to get the generator control unit replace due to ant damage last weekend. The guy swapped out my agm for a conventional vented battery for no reason and now I have a spare agm that looks a little underpowered for a car. Any thoughts? I was happy at least that my wife stopped him from taking away my fairly new agm. That alone seemed odd since the date is right on the battery.

I too have to get a new battery for mine as it's likely dead as a stump at this point. I'll grab something out of my stock on the van and get it off the trailer to get it in the garage. After that I'll take a drive over to Batteries Plus to see what they have. The AGM sounds like a great way to go. Probably add a battery maintainer at the same time.

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Sure, you could use this, but I wouldn�t recommend it unless you never take long trips and the car lives on a trickle charger. With less than half of the RA of the battery rated for the 996 and down about 300CCA, a heat soaked engine on a hot day may struggle with this battery if you�ve been running the AC and other accessories before you leave it in a parking lot for a few hours. Lots of options out there, but when I was shopping a few weeks ago, I wanted the highest rated battery in favor of weight savings. 10lbs of extra weight in the battery box isn�t something I�m concerned about given I don�t track the car and don�t feel it�s underpowered in any way. If you can find a Pep Boys near you that�s still open, this is a great deal... https://www.pepboys.com/champion-pre...779?quantity=1

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I figured it was a little underpowered based on the 600 cca indicator but figured I would ask.

^ +1 I had an AGM in one of the cars for weight saving factor but it was not happy when I needed to start the car soon after shutdown on a hot day (which is pretty much every day here). I sold it to a guy for his track toy and went back to the AutoZone option. Note to self: clean battery tray.

Do you have details on the lithium battery? Is it something you've done? I'd love the weight savings!

Do your products ever go on sale?

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Wasn't sure if you were addressing us directly but included some links for you below in case this is what you were looking for. https://rennlist.com/forums/vendor-a...l#post16886858 https://rennlist.com/forums/vendor-a...-day-sale.html

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Wow Batmobile, sorry you're so angry....I see you have made a point to post in 5 other Rennlist threads about how awful a company we are. I have no problem with criticism provided it is honest, and creates a dialog directed toward resolution, but this has been an extremely aggressive attempt to hurt Antigravity and portray us as some non-responsive company. The fact is your statements are not entirely accurate in the way you are portraying this. So I will respond and hopefully find resolution. The simple resolution is just for you to send the battery back and we will fully refund you. I cannot refund your Canadian Tax Fees and or charges Canada puts on products.... that has nothing to do with Antigravity Batteries, we didn't even know about them.. But for the battery, heck yea we'll refund you, we'll do that for anybody who doesn't like our stuff or has any issues. Also after revfiew of the email chain you never once said you were stranded, Nor did you say it was defective on arrival you contacted us 3 months later and said you had and issue. You said it looked like the RE-START button was sticking. Anyway I won't argue this issues, I see you super angry. But lets keep the facts straight please. We have actually responded to you and I show below. I'm sorry we are not paying for your fees incurred from Canada but they are not related to us. Unfortunately, because you statements have been so critical of our company I am forced to respond with the facts so the reader can understand the realities. This is actually very simple. 1- You bought the battery in Dec of 2019... we shipped it to Canada for you. You wrote to us a couple months later stating you had an issue with the battery (oddly you never brought up being stranded like said in some of your posts). We immediately responded, and we gave you documentation on how we handle the warranty, and how to send the battery back to us so we can do the warranty. 2- You then wrote back and stated you wanted a NEW battery shipped to you at our cost without shipping the original battery back to us. My staff said we could not do that and we required the battery be shipped back to do the warranty. You then stated that you wanted us to pay shipping from you to us and the staff again informed you we don't pay shipping from the Customer to our Offices as part of any Warranty Claim, and that is documented on our Warranty claim form. Please note returning a product is normal business practice whether you buy an Auto Part, or a Toaster, you have to send back the product back to get warranty service, or a refund. 3 - To date you still have not sent the battery back to us. We have not avoided you, we didn't even think about it actually because we figured you were sending the battery back. We have told you a few times to just send it back yet you keep wanting us to pay certain things for you. I'm sorry about that policy affecting you like this, but we just want to get the battery back and we'll refund you. The bottom line is we just want to get the original battery back to warranty it, yet you have not sent the battery back while claiming we are horrible for not paying your Government fees. Please just send it back we are glad to refund you. We need to understand what the problem could be, to recover the valuable parts in the battery, and see if there was a manufacturer issues or something else and learn from it. I have said we will fully refund you. So just send it back and we can get this done. If you aren't doing that then we can't help you, you have to be involved and take that action.

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As mentioned on my other post, I will send it back for refund. Your staff had refused that option.

Aside from the standard offerings, I've used both Braille and Odyssey lightweight batteries. Never had a problem with either, though the Odyssey didn't seem to last as long as the Braille batteries in my experience. I had an Odyssey in the 996, it lasted 2 years. I have an Interstate in the car now. Mike

Hi with last post being just under 2 years ago I thought I would check in again. What's the groups preferred 996 [and tray if needed] 996 battery for May 2022?

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In my opinion (and the opinion of many mechanics), Interstate batteries are the best. If you have a Costco membership, the Interstate MTP/H6 is $115 and is the way to go in my opinion. My old Interstate was the H7 (one size larger) and lasted 11 years (H6, H7, and H8 will all fit in the stock 996 tray). The H6 is about 8lbs lighter than the H7 and has plenty of power. I prefer the standard Interstate batteries over AGM -- AGM does perform slightly better, but I think wet cells are still the most durable. The Interstate wet cell (MTP/H6) is also about 8 lbs lighter than the equivalent AGM Interstate battery. More info can be found in this thread => https://rennlist.com/forums/996-foru...n-a-996-a.html

Agree with Peter.

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I'm nominating this for "post of the year". Congrats!

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Hah! Do I get a free interstate battery?! 😁

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Yes, but there is a $115 "convenience fee" for the privilege of being able to pick it up at your nearest Costco.

Just thought I'd add that I bought an Antigravity Lithium battery. Yes, they're really expensive. No, they're not the most cost effective option. But, the technical content and questions that they've answered about batteries in general has been extensive, while only mildly pointing out their product. The battery has worked great for a year. I even left it connected while doing some winter maintenance, and it had shutoff. I hit the button, the car started great. Put it on the charger after that though. I had a few questions, and their customer service was very responsive.

My understanding is that there are only four companies that make batterie. The rest are all just branded. H7 maxx from Wally World does the job just fine.

I just had my dead battery replaced by AAA by their roadside assistance. Pricey at $180 but it's done and has a decent warranty I guess. Saved me the time of going to Autozone and replacing myself and going back to return the old battery.

I'm a DieHard Intestate fan.

https://www.cnet.com/roadshow/news/b...0manufacturers .

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Most battery brands, including Interstate, are built by Johnson Controls. I hope someone will correct me if I am wrong, but I think every battery brand specs out their own unique designs for batteries and Johnson Controls builds their batteries to their exact specs. There may be some generic battery brands that are "cookie cutter" designs (e.g. same battery under different labels), but I believe name brands like Interstate are unique batteries with unique designs regardless of the fact that they happen to be built in the same factory. I do think there are other battery brands that are also very good, but I've only seen Interstate be almost universally recommended by high-end mechanics. To me, Interstate is the "nobody ever got fired for hiring IBM" brand for batteries. That doesn't mean other batteries aren't also great, but Interstate is the safest bet in my opinion. .

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That is the absolute facts... they vary even in the same model just a different batch.

I'm bought an Interstate AGM battery from Costco in H8 size ($184). I tried installing it, but the screw from the clamp doesn't engage any threads. Pulled the battery back out and realized only the H6/H7 holes have threads. Is the idea that H8 fills the tray completely so it doesn't need the clamp? Seems weird to me, but I also think it would take a wild bump to bounce an H8 battery out of the tray. I went with the H8 AGM because I don't drive the car much and have to put it on Battery Tender after a few weeks. A few extra pounds seems worth it for less hassle. Should I just bring it back to Costco and get an H7 AGM?

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No, the battery needs to be secured. Yes, the H8 is the incorrect size.

I am running AGM H8 battery in both C2 cars, I also rivnut the battery tray for the battery hold down. its great having high CCA from the H8. Battery tray are very easy to remove and add blind rivnuts.

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I replaced my 11-year-old Interstate H7 with an Interstate non-AGM H6 from Costco last year and have been very happy with it. I went non-AGM intentionally just because I think traditional batteries handle discharge events better than AGM, and I don't like using a tender all the time when parked. The H6 non-AGM weighs 38.9 lbs ( https://costco.interstatebatteries.c...733&Country=US ) versus 45.4 lbs for the AGM H6 -- so non-AGM is 6.5 lbs lighter in H6 form. I can't find the weight of the Interstate H8 AGM, but I imagine it's significantly heavier than the 38.9 lbs of the non-AGM H6. Of course, if you really care about weight, Anti-Gravity is the way to go, but there are some meaningful weight savings going with the H6. I kind of "settled" for the H6 after being unable to find the Interstate H7 I had before, but I haven't found the non-AGM H6 to be deficient at all, and the weight savings are an added benefit -- so I'm glad I ended up with the H6. Your mileage/usage may vary however .

Just replaced my BatteriesPlus DuraCell from 2016 in June 2023. Always kept inside on trickle charger. Old was the 3 year liquid with vent. New is the AGM version, Figure I�ve earned it.

Hmmmm you guys are running your batteries longer than they should be? I am freaking out since I just got my Targa a month a month and reading up getting locked out of the frunk lol....house sitting next week and I am going to have a change to do some minor clean up and repair and replace small items

911 Dreamer. When you replace that battery, while you are in the auto parts store gets some dielectric grease. When you install the new battery, put the grease on the posts and make sure the clamp sits all the way down on the post. The grease will limit corrosion that is visible on your clamp here in the picture.

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Thanks will do!!!!

Another suggestion is to wrap a single stripe of electrical tape around the black part of the positive cable to make it clear which side is positive. It's pretty difficult to see the + and - labels on the battery, especially with the terminals in place, since it's so far back in the frunk, so the red stripe on positive makes it idiot proof.

I am so glad I saw your post in a quick search as my Duracell Ultra Platinum AGM is flat! Just called BatteriesPlus and they are going to replace it free under warranty. I did not realize it had a 4-year replacement warranty which is stellar! I purchased it in late summer 2020.

I figure my car is 25 years old and whatever battery I buy today must be better than what it came with regardless of brand. I can�t imagine Porsche was spending extra on the battery when it was saving as much as it could in the interior plastics. So Walmart got my money and I�ve had zero issues.

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The Walmart Platium Models are the same battery as many of the High-End Brands like Bosche and Die Hard. If you look at the Case it is exactly the same as the Porsche Branded Battery (Banner) too, meaning the same manufactuer. They are a excellent battery and very cost effective. Most all of the Lead/Acid Batteries are just rebranded but made by the same company to the same specs, just different lable.

I never got to install a new battery from Costco, they were out and had no ETA on new ones. I was going to call again in March around the same time I was going to get an oil change at my Indy shop. The cars been running fine and no start or battery issues, but will still get it done for POM. I have a question for the group though, Is there a way to reset the memory seat options with the battery out? or how long to leave the battery to reset it? I am having a issue with the main key when the vehicle is unlocked, where the memory seat options goes back the POs settings and I have tried to reset as per some threads on here and that doesn't fix it. The 2nd key doesn't do this, as I tested it out for a couple of days.