golfnutintib

I would be in for at least 2-3 units at the outset, maybe more after my initial trial, so long as I am furnished with suitable mounts for the OEM battery well/location in 964/993...

All my air cooled cars are street cars but they are stored properly and have trickle chargers connected when not in use.

As Jack mentioned elsewhere if I take one of these cars on a multiday trip I will bring trickle charger and/or jump starter...

kos11-12

Just went out for the day, the 480 cca battery cranked the engine well !
I also carry a Ctek lithium charger, and have a cut off , always cut the battery when parking, never live anything on when shut or start the engine ,

golfnutintib

kos

curious -- is it that critical to cut the battery even if, say, parking for a long dinner or an overnight stay?

does the battery drain that fast, even in an old car like a 964 with minimal electronics load?

kos11-12

Hi Golf,
Its been about 6 years I use lightweight batteries, 1 Odyssey, 2 lithium.
I sometimes don't cut when I live the car for about 2 hours, but I am not to far and always have a eye on the car,
I often cut (from a 6 connections cut off) the battery to save it, and remove the steering when living the car for a long time, locking the wheels side ways,
for security reasons....

Foxman

Foxman

golfnutintib

got it - thx kos

fox - car was outside in MA winter for 3 weeks and that battery held charge? damn -- almost TGTBT

Foxman

Vandit

What standard posts are you guys using?

I don't want to mod the car's battery terminal wiring.

I bought some battery posts at the auto parts store that accept a 3/8 bolt from below but a 3/8 bolt is too big for the Battery Tender terminals.

kos11-12

Hi Foxman,

nice cars, the 93 looks awesome !

Foxman

Voltphreaks carries these aluminum adapters to convert from M6 to SAE top posts. They came with the VPR P6. https://p10.secure.hostingprod.com/@...roducts_id=143

Thanks Kos. The 993 has been side-lined on that lift for 18 months waiting for RS wheel carriers. I just finished installing the new suspension (thanks to BBI for the wheel carriers), and she's finally ready to return to the track!

Antigravity

For sure we will be offering a discount to Renn Listers....

I also wanted to point out.... if you are tracking the car it is ok to use a lower amp hour battery and smaller lithium batteries.... because you are on a closed course and not out on the roadside where a emergency would take place. If you're diligent with your battery maintenance and keeping the the state of charge up, you're a good candidate to use a smaller lithium battery, but being realistic who wants to go to a hotel or be on a road trip and have to put sure battery on a maintainer or charger or feel you can't leave your battery for a week or two without it over-discharging. So just take into consideration your application.

Also on low Ah Batteries it doesn't offer enough emergency amp hour capacity if your car died on the side of a twisty mountain road where you would want your hazards to be left on and keep staying on for a good amount of time, you would also want something with enough capacity for keep attempting start attempts. Really small batteries, can easily start the car a good many times... but if you have a roadside emergency where you need to keep trying start attempts that is also another area where the smaller batteries are not the best option. My point is you just try to look at the overall picture of what you're getting into and you do want emergency backup power so you don't want to cut the battery as small as possible unless you're racing or tracking. I'm just bringing this up to express some real-world facts that you guys may want to consider if you're planning on going with the smaller style lithium batteries, because you don't want to be a hassle for you overall.

If you do go with one of the really small models and you're going with with a Volt Phreaks battery, our our Antigravity Battery, these both have a low-voltage cut off protection , and that is what is key to saving your lithium ion battery from damage because we both offer a low-voltage cut off.... Most if not all the other lithium ion batteries do not have a low-voltage cut off such as the Battery Tender Deltran models, so if you overdischarge that Battery Tender style of another brand like that your damaging the cells and then if you jumpstart it from a severely over=discharged state they can go into a thermal runaway becuase lithium hates being charged by the vehicles system if it is in a low voltage state below 10.5v. The Vehicles Charging system will fast charge a low voltage lithium battery not knowing it lithium and the lithium won't like that. So that low voltage cut-off also prevents that potential.

From my personal perspective you want to make sure you have about 15Ah of REAL Amp Hours in your car. REAL amp hours are different from what some companies claims because a lot of companies are putting the lead acid equivalent rating for the lithium battery. so you might want to ask those companies what the real amp hours are because yes you can certainly get away with a smaller battery, we have a two amp hour battery that will start any Porsche.... it weighs just under a pound and can start a Chevy 350 without issue. But the issue is the amp hour capacity, 2Ah won't get you far if you leave something drawing on that. 15Ah should get you a week if not much longer sitting but again as some of the other posters mentioned you really need to check out your milliamp draw to fully understand when your car is drawing the most energy and if you can get it into a state where you are drawing exceptionally low milliamps. And on older Porsches...meaning over five years old... you definitely want to check this out so that you can make sure there was not some funky high parasitic drain going on that's can create a significant draw on your smaller lithium battery which will then lead to frustration with your battery. But if you check all the stuff out and you're diligent you can go with set ups like some of the guys above have without any issue because lithium is so powerful it starts the cars quite easily.

Antigravity

You can also get some here.... https://shop.antigravitybatteries.co...-adapters-sae/

If you have a M6 thread on your Battery Tender model these will screw directly into your rectangular carrier bolt for the BT type battery.. if you have an M5 for that Carrier bolt, you just get a smaller Allen head M5 bolt to screw into your Battery Tender Carrier bolt. Our kit has the M6 bolt.

kos11-12

kos11-12