Scott O'Connor

My mechanic hates lithium batteries due to these kinds of issues. A huge time suck for him when his clients come in with them and troublesome faults. These particular faults are serious; I can't/won't track the car with them, hence the more immediate remedy approach.

I may go back to the lithium this summer after the track season kind of ends due to heat, and I have more time to tinker with fault finding.

I do appreciate the additional, insight, thanks for that.

brewerbry

I have a 2014 Cayman S with an Antigravity Lithium battery and have added a Garmin Catalyst and a phone charger powered by the usb plug in the glovebox and have had ZERO issues with the battery. Just want to point out that there are many of us that do not have problems with the Antigravity battery even with added aftermarket accessories added to the car. I know my car is not a GT4 but still, no problems. Just my 2 cents.

Last_935

I have a consistent parking brake failure fault code on my car with the oem battery. Every time I clear it, it comes back.

DR.S

Haven't read the thread, but:
I had same issues immediately after changing to a LiFePO4 battery due to too high voltage > 15 V (old OEM battery was "dead").
After coding "lightweight battery" via PIWIS everything was fine and max. voltage dropped to 14.5 V.

The car BMS raises the voltage when the battery gets older / weaker.
This can lead to these issues when you change to a LiFePO4 while your OEM one is already in bad condition.

lgmike

Another tail-end comment to help (maybe)? If you're using iCarSoft to set your BMS....

I had an end-of-life OEM lead acid battery in my 991.2 (Carrera 4 GTS). I decided to switch to an Antigravity H6, and reset the BMS after fitting it. I then had all of the warning flags and symptoms described by others here (all confirmed as over voltage fault codes, using the iCarSoft CR Max). I could see the battery voltage climbing way over 15V.

I think this might be what causes it: after watching a well-linked YouTube video, I did what they did and I set the new battery type to 12V wet. When I subsequently changed the battery type to AGM, everything miraculously settled down. These two profiles are very definitely not the same.

If you don't reset the BMS, the chances are good you'll be fine, since that will be carrying over the AGM profile. I wanted to reset mine, though, because my BMS was used to a battery that was so degraded it only held about 12.1V and the car was using the alternator way too much. So if you reset the BMS when you fit an Antigravity battery, make sure you set its type to AGM, I believe that's the trick.

Michael

Jawnathin

Great tip, thanks for sharing. Too late for me as I’ve moved on from AG batteries but I hope your tip can help other owners experiencing any issues.

Souljourner

This is great advice.

I am curious if any of you have tried setting the battery type to “lithium ion”?

I’m using the foxwell NT530

DR.S

Yes, I coded it via maintenance of vehicle data.

colnagoG60

FWIW, I had this error when I bought my CPO 981 GT4. Dealer's head mechanic spend ~2-3 hours adjusting brakes via laptop. Error went away, but I sometimes hear brake squeal when turning and reversing into a parking spot.

kitwetzler

Sorry for necro posting on an old thread but I did not heed the warnings on my 981 Spyder and installed a 40ah Antigravity battery. Yeah, it was great until it got consistently below 50 degrees and then I started to get all sorts of fun problems. SES light and parking brake failure, overvolting codes, etc. It was showing up to 15.5 volts. My BMS was properly reset, I tried both lithium ion settings and AGM... neither worked. I don't know what the problem is, but I gave up and went back to the stock AGM battery. I emailed antigravity and... crickets .

Snowy999

This battery seems to have intermittent problems with the 981 GT4 charging profiles. AG were excellent and took mine straight back. Reading more widely i believe 718GT4 and GT3 all fine. Instal a Liteblox battery, more expensive but BMS was designed fir 981 GT4 and copes with the low temperature high voltage charging. I often see 15.2V at sub 5 degrees C but no faults.

NoGaBiker

Man, it sounds like y'all are risking all sorts of serious annoyance (or worse) trying to solve a problem you don't have. Namely, what's wrong with the OEM battery? A little weight? Seriously? Is the car suddenly much funner because you saved 20 pounds?

Snowy999

It’s the sum of the parts!

Akra exhaust
Liteblox battery
PCM and speakers delete
18” Apex wheels
Carbon buckets/CCBs
Euro clubsport cage, extinguisher and harnesses out

weighs c.1340kg (with full fuel but no driver) about 100kg lower than many Ive read. Def makes a difference in autox and hillclimbs!

but it is really just part of the fun of owning my GT4…

NoGaBiker

Oh I get it, been down that road before on other cars. It's just these aftermarket batteries seem to cause pretty frustrating problems fairly often in the GT4. Most of the other things don't. So I'm just looking at the actual weight savings of the battery swap, vs how troubling it seems to be for a lot of guys on here.

ajw45

I got the 60ah or 80ah, I forget now, and aside from it simply being physically easier to swap in a much lighter battery and the weight savings, I like that I can check my charge level via BT. In the winter months like now when the car sits I jut check the app on my phone once in a while to see if it needs a charge or a drive. TBH though, the battery discharge is so low it can last all winter np.