Demonic
Well-Known Member
- Thread starter
- #1
Hey guys,
So many of us are always on the hunt for good ways to ditch dead weight on the GT350/Rs, and are familiar with the Braille lithium batteries. A newer entry to the market is Antigravity. They're US-based, and the owner, Scott, is a Porsche GT3 owner who's been active on Rennlist promoting the batteries. He has two new batteries now - the ATX30 and RS30. I had talked to Scott about him joining the forum and possibly doing a group buy for us on the ATX30, but he wasn't sure if the demand for lightweight lithium batteries in the GT350 community is as significant as it is in the Porsche community. So I've decided to guinea pig this myself. I had planned on posting a review once I receive the battery, but his site currently has a Memorial Day promotion of 15% off, so I'm posting now just in case anyone else wanted to grab one. The ATX30 is normally $399, so with 15% becomes $340. The discount doesn't apply to the larger RS30.
The ATX30 weighs 5.75 pounds, and the smaller dimensions than the stock GT350 battery should allow it to simply drop into the stock compartment, but I did also buy the spacer foam just in case. It has 30 Ah equiv (18 Ah true), and 880 CCA. I won't get into a discussion of conversions between lithium CCA and lead acid CCA, but it's plenty to turn over a V8. The stock battery is a group 99R (which I believe may be some Ford specific sizing equivalent to a 67R?), has 390 CCA (according to the label, though online listed at 470, so it may have changed or the way it's measured changed), and if I'm not mistaken 45 Ah. Weight is listed at 30 pounds, but I haven't weighed it myself yet. So the ATX30 has more cranking power, and 2/3 of the overall power capacity of the stock battery.
Something very important to note: one of the reasons for the expense of good lithium car batteries in the past was a proper battery protection and load balancing circuit built into them, often called BMS. The ATX30 has BMS - over charging protection, over drain protection, and load balancing between the cells. It charges normally off the car's alternator, and is therefore a drop-in solution. If the battery is discharged to a certain threshold, the battery has a built in cut-off reserve to prevent parasitic drain from taking it down to dead zero. For using an external charger/tender though, you do have to use one specific for lithium car batteries, which is also sold on the site for $59. You'll also need the SAE auto terminals that screw onto the battery allowing it to be connected to the stock battery connections.
Morris Engineering currently makes an aluminum bracket for the S550 Mustang chassis for his older ATX24 battery, which is a smaller capacity. On other forums, members have been happy with the ATX24, and been able to leave the car for a couple weeks without a tender and still easily start it again. So I think I'll be fine with the added capacity of the new ATX30 despite my car not being a daily. I did order the tender though. Scott said if there's enough demand he'll try to produce a CNC'd aluminum bracket to replace the whole battery tray in the S550, just as he's just done for the Porsche guys.
https://shop.antigravitybatteries.com/products/starter-batteries/automotive/atx30-rs/
No affiliation here, just providing the info for anyone else looking to drop 20+ pounds off the front of the car. I'll report back with more when the battery arrives.
So many of us are always on the hunt for good ways to ditch dead weight on the GT350/Rs, and are familiar with the Braille lithium batteries. A newer entry to the market is Antigravity. They're US-based, and the owner, Scott, is a Porsche GT3 owner who's been active on Rennlist promoting the batteries. He has two new batteries now - the ATX30 and RS30. I had talked to Scott about him joining the forum and possibly doing a group buy for us on the ATX30, but he wasn't sure if the demand for lightweight lithium batteries in the GT350 community is as significant as it is in the Porsche community. So I've decided to guinea pig this myself. I had planned on posting a review once I receive the battery, but his site currently has a Memorial Day promotion of 15% off, so I'm posting now just in case anyone else wanted to grab one. The ATX30 is normally $399, so with 15% becomes $340. The discount doesn't apply to the larger RS30.
The ATX30 weighs 5.75 pounds, and the smaller dimensions than the stock GT350 battery should allow it to simply drop into the stock compartment, but I did also buy the spacer foam just in case. It has 30 Ah equiv (18 Ah true), and 880 CCA. I won't get into a discussion of conversions between lithium CCA and lead acid CCA, but it's plenty to turn over a V8. The stock battery is a group 99R (which I believe may be some Ford specific sizing equivalent to a 67R?), has 390 CCA (according to the label, though online listed at 470, so it may have changed or the way it's measured changed), and if I'm not mistaken 45 Ah. Weight is listed at 30 pounds, but I haven't weighed it myself yet. So the ATX30 has more cranking power, and 2/3 of the overall power capacity of the stock battery.
Something very important to note: one of the reasons for the expense of good lithium car batteries in the past was a proper battery protection and load balancing circuit built into them, often called BMS. The ATX30 has BMS - over charging protection, over drain protection, and load balancing between the cells. It charges normally off the car's alternator, and is therefore a drop-in solution. If the battery is discharged to a certain threshold, the battery has a built in cut-off reserve to prevent parasitic drain from taking it down to dead zero. For using an external charger/tender though, you do have to use one specific for lithium car batteries, which is also sold on the site for $59. You'll also need the SAE auto terminals that screw onto the battery allowing it to be connected to the stock battery connections.
Morris Engineering currently makes an aluminum bracket for the S550 Mustang chassis for his older ATX24 battery, which is a smaller capacity. On other forums, members have been happy with the ATX24, and been able to leave the car for a couple weeks without a tender and still easily start it again. So I think I'll be fine with the added capacity of the new ATX30 despite my car not being a daily. I did order the tender though. Scott said if there's enough demand he'll try to produce a CNC'd aluminum bracket to replace the whole battery tray in the S550, just as he's just done for the Porsche guys.
https://shop.antigravitybatteries.com/products/starter-batteries/automotive/atx30-rs/
No affiliation here, just providing the info for anyone else looking to drop 20+ pounds off the front of the car. I'll report back with more when the battery arrives.
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