Achtung964

They are having a Labor Day sale this weekend. For those who have bought one lately, which one did you go with and how has your experience been so far? I have no affiliations with the company.

Mike Murphy

I think most folks are happy with them. For those with an expensive high performance car, this is one of the best mods you can do. Shaves like 30lbs of weight.

Mike Murphy

https://rennlist.com/forums/997-gt2-...est-model.html

Goughary

I just jumped on here after a long day at the track. Interestingly enough i was just talking to the guy that builds our racecar, and he was going on and on about the antgravity battery he is using in his STU car- raving about how much he likes it and how strong it is. I'm leaving out names, but it's a very strong endorsement. So if weight were a concern, I'd give it a try.

I use their battery tracker product on my 964 and like that a lot. No brainer product.

Antigravity

Hi guys, just an fyi that I can extend the same 15% to you guys on the battery anytime as a special for our Rennlisters. For the 964's the H6 is the fit and of course if you have any questions all feel free to let us know!
chad@antigravitybatteries.com

Mike Murphy

Is there a way to convert a traditional CCA-type battery to AH?

Antigravity

Mike it does not work like that. They are two seperate things.

CCA mean Cold Cranking Amps. That is the current a battery puts out under a formula taking into consideration a load until the battery reaches 9v.
Ah is the Amp Hours of the Battery. That is the Capacity in terms of Amp Hours in a test of its ability to discharge current under a certain load for a period of time.

But forget the technical testing stuff it too long to write about. Cranking Amps are the Power of the Battery and Amp Hours are the Capacity of the battery.

What are you trying to better understand? Whats you application?

Michael Russell

Over the last 3 or 4 years i have done a lot of rc’ing with Lipo batteries and if there is one thing you learn, it’s how much respect you must have for these batteries. They are extremely temperamental and it is pretty easy for a small problem to turn into a big one. Do a quick search for “lipo fire” and you’ll soon see what i mean. In Addition, Lipo’s tend to have fairly short total charge cycle lives, somewhere in the 100-200 range. Now, i would not expect car batteries to be fully cycled, but Lipo’s dont like remaining fully charged either, which can significantly shorten their life. Manufacturers all seem to recommend keeping the batteries at a”storage charge” of around 35-40% if you aren't planning to discharge the battery in the next few days to a week. With all of this going on, how are managing both the safety aspect of the batteries as well as their life-expectancy?

thanks
Michael

Antigravity

Hi Everyone, Just a couple things to clear up here...I'm guessing when you refer to your RC Lipo batteries you are referring to a Lithium polymer...and to start you would not use LIPO as an Automobile Starter Battery. Some may confuse LIPO Batteries in Remote Control Toys, Phones or Hoover Boards with what is used in the Automotive Starter Battery but that is certainly not the case here. We use Lithium-Iron Phosphate LiFePO4 in our Batteries, which is a safe and stable form of LITHIUM-ION. We have a full Battery Management system that protects the battery from Over-Charge, Over-Discharge, and has Thermal Protections. It also has Short Circuit Protections. So its a pretty fool proof battery that cannot be damaged. Also Lithium Cells are rated at TWICE the Life Cycles of Lead/Acid... so you're talking double the life span (with LiFePO4 about 2000-2500 cycles), but when you add in the Battery Management System that does not allow for the battery to become OVER-DISCHARGED, and the fact that the battery has built in WIRELESS Jump Starting you are talking another level of Stater Battery.

While I'm sure most have seen some of the flaming battery videos like with the Hooverboard battery fires, that is not remotely what we are doing, nor does it represent Lithium Auto or powersports batteries. It does however show a little bit of mis-information out there for the average Consumer about Lithium. So for us its about education on this type of product. We understand it's new, and with the media generating information about fires from LITHIUM-ION we understand that. But for those who don't know, "Lithium-Ion" just means ANY rechargeable Lithium battery chemistry. But under that umbrella term "LITHIUM-ION" are SEVERAL different types of Lithium-Ion chemical make-ups like a Lithium Polymer such as Lithium Cobalt which is rated at 500-1000 cycles. They operate at different voltages and some are very safe, some are much less safe, but as stated the variant used as Starter Batteries are Lifepo4 and are a safe direct replacement for lead acid while being up to 70% lighter. In addition a few current manufacturers are using them in their performance Cars now such as Porsche, Mercedes, BMW and others.

Michael Russell

Thanks Antigravity, that is a helpful and much appreciated explanation.

Michael

Mike Murphy

It’s just that most people who shop batteries are used to seeing the CCA rating and not the Ah rating. My car came with an Interstate that says 730 CCA (910 CA), but I don’t see anything about Ah. So while I agree that these two are different terms, the people buying them might want to equate the two.

Antigravity

Hi Mike, the Ah should be right on the battery but I think it may be this one in the image below or very similar to it. As you can see it's rated at 70Ah, quite a large capacity as are many of the OEM stock lead/acid batteries that come in cars. This is part of why we emphasize how important capacity is in regards to daily driving vehicles because of the consumption they may carry. The cranking amps however believe it or not are a no brainer, while technically cca (cold cranking amps) is a designation reserved specifically for lead acid, the cranking amp rating of lithium is similar but out performs lead/acid night and day as lithium puts out a constant peak output where lead/acid will steadily decline the longer it's drawn upon. But in our auto batteries you're looking at a minimum of 1000 cranking amps with a 24Ah option and going up from there with the larger Ah sizes so starting cranking power should never ever be an issue...hopefully that helps but please let us know if you have ever have any other questions.

Antigravity

Hi Mike,

Scott answering here.... I now understand your original question. Make sense and we might be overlooking something due to being too "close" to our battery and not understanding what the customer is looking at.

Since Lihtium is so powerful we are rarely pointing out the Cranking Amps aspects. With Lithium Batteries the cranking current/power is about twice that of lead/acid. So even our very tiny batteries can start any Porsche. But though lithium is 2x the cranking power of lead, it also has LESS Amp Hours than the same size Lead Acid battery... so since most the performance guys are looking for the lightest option we usually talk mostly in Amp Hours since those directly correlate to how long the car can sit without needing to be on a Charger.

But within all those Amp Hour numbers there is an issue that Lead/Acid batteries have which is called "Self Discharge" , which means that a Lead Acid battery actually discharges while sitting ... so if you take a 40Ah lead battery next to a 40Ah Lithium... though they are both the same Amp Hours the Lithium would retain its voltage much better since it has massively less natural "self discharge" than a Lead/Acid Battery. So with all these factors you can get away with a lower Amp Hour Lithium Battery in a Car and not have to match the number that the Lead/Acid manufacturers quote in their specifications.

Sorry if that make things more confusing... but it is sometime hard to explain while writing this stuff out.

Mike Murphy

Hi Scott, it all makes sense to me. I think it would be a selling point that your batteries can produce more CAs even if it’s not super relevant to the application of track cars and race car.

I used to run my batteries pretty hard when I was into car audio (alternator off) with 20-30amp average draw for several tens of minutes. Now I treat my batteries well. I never leave the lights on or drain the battery. I start the car and drive off immediately, especially when I need to use the heated seats, lights, heater, etc. For my type of use, even the smallest Ah battery you provide would be more than ample and save a large amount of weight.

I also don’t let the car sit. It gets driven often.

911Jetta

One month in with a ATX-30RS, and no issues so far. The car sat all week, then immediately fired up Saturday morning.
Also had a 5 lb. 680CCA Battery Tender for almost two years before this battery.