991.2 gt3 Lithium battery - Page 1 - 911/Carrera GT - PistonHeads UK

Morning all, There has probably been a thread on this, but struggling with the search.... I was thinking of fitting a Lithium Battery in the Spring due to the large weight saving over the standard AGM battery. Has anyone on here done the same with a 991 gt3? If so, what make did you fit and did you need to make any changes to the PIWIS? I was thinking the Antigravity H8 size looks good. Many thanks, Mark

I’ve fitted an Antigravity battery to my 991.2GT3 R/S and no problems whatsoever. If the car is laid up for more than a month especially in Winter best to use a Ctek Li battery trickle charger. Weight saving is about 14kg btw

Thanks Taffy. Do you rack your Gt3? Reason I ask is that Antigravity seem to suggest that you should get the PIWIS re-programmed to lower the charge going into the Li battery at consistent high revs

Did nine track days in it this year and no problems. Left PIWIS be .

FWIW same make of battery on my 997.1 GT3. A few notes: Car starts one turn of the starter sooner than with old battery. more cranking power. Not sure if this is better or worse for engine wear on startup. You cannot jump start with leads from an ordinary battery! For same reason as above, you will also need a Li specific charger, which Ctek do offer. Loads lighter though.

Thanks gents

https://www.antigravitybatteries-uk.co.uk/automoti... It seems that even "jump starting" is covered ? Internal control circuitry appears to make this battery a straight replacement with no modification (other than a Li battery conditioner) required ....

Any warranty issue? Mate is saying change will void Porsche warranty, which seems harsh!

Any experience of Deadweight or any other lithium ion batteries?

Lithium batteries (LiFePo4 chemisty and possibly other Li chemistries) should not be charged / receive current if the battery is ideally below 5C and definitely not if below 0C. They get damaged if charged at low temperature If you plan on using your car in these conditions, LiFePO4 batteries are not a good choice unless they have a heater element in them that sends the charging current to warm the battery first . Probably not a great idea unless you understand the limitations and don’t use your car in low temperatures and i appreciate a GT3 might not het used in cold temperatures. As the 991 batteries are in the front, and the motor is in rear, they won’t get any heat soak to warm them LiFeP04 batteries have a different charge profile and usually require a steady input of 14.2V- 14.4V, so the standard AGM programme from teh car may overcharge a LiFePO4 battery. If the car has the ability to regulate the alternator output to a specific lithium profile via PWIWS , i would certainly do that change, as the charging profile of Lithium is very different to a flooded lead acid or AGM battery. (Lithium can soak up a lot of charging current easily and charge much faster than an AGM batter, and don’t need a float cycle etc) Edited by elan362 on Saturday 23 March 19:56 Edited by elan362 on Saturday 23 March 20:06

I have a tiny cheaper LiFePo4 battery I use on my 996 and 986 - about 250 quid and less than 2kg. Swapping it between the cars - pics below. I did put it in my 981 for a few days but only while parked outside. The leads were quite stretched so I did not want to drive it like that. I tried starting it and the car started fine and showed no errors or messages. So I'd have no problem using a LiFePo4 battery on the 981 but I would need a better solution for cables and then some way to mount it. On my 9x6 cars it works fine but will go flat if the car is left and not used for about 3 weeks. My cars live outside and are locked shut so getting back in is a right royal pain in the A once the battery goes flat. Also I charge mine just fine with a cheap 13 quid Lidl charger. It isn't a charger designed for use with LiFePo4 batteries but most modern LiFePo4 batteries try very hard to work or act just like a simple Lead Acid so they should be basically interchangeable.