peterp

I'm of the same mindset. I'm not always convinced that newer tech is better when it comes to batteries. I had Optima red tops and a yellow top gel and didn't like either (red tops couldn't handle being drained, yellow top (deep cycle) could handle being drained but lower CCA). I guess both would have been fine with a constant trickle charger, but I found flooded performed much better long-term.

I'm happy to spend $50 or whatever additional for AGM, but not sure its long term durability is better (though cranking is clearly better). It sounds like AGM's for the 996 are heavier even though, theoretically, AGM should weigh a lot less. Our 996 is driven sporadically -- enough not to use a trickle, but it's not unusual for it to sit a week or two. It seems like flooded might be better for that scenario.

Antigravity

Well this is my side of the fence...so I can add a few things....

To clarify Lithium-Ion does not define the type of Chemistry of the particular Lithium-Ion Battery you are using. "Lithium-Ion" is an umbrella term meaning any re-chargeable Lithium Chemistry based batteries, though the public usually thinks it means all Lithium batteries..... So a "Lithium-Ion Battery" can actually refer to any rechargeable lithium chemistry like (Lithium Cobalt / Lithium Polymer), Lithium-Iron Phosphate, or Lithium Manganese, etc. So you have to specify the chemistry if your talking about Automotive/Motorsports Batteries.

Lithium-Iron Phosphate (Lifepo4) is what the companies like Antigravity Batteries (me), Braille, and others like Volt Phreaks use in their Motorsports Starter Batteries. So if you're interested in this type of Battery then it will be made using the Lifepo4 Chemistry which works and operates in the same voltage range as 12v Lead/Acid Batteries. And within that there are varying degrees of cell quality, and level of built-in protections in the form of a Battery Management System (BMS) on-board, and also how technologically advanced they are... for example our Antigravity Lithium Batteries have built- in Wireless Jump Starting, so you can never be locked out of your frunk or not be able to start your car if it has a dead battery. Simply press the provided Keyfob and the Antigravity Battery awakens with its reserve supply of power and can start your car or just provide the power to your system so you can operate the frunk to put it on a charger.

As for Lithium being more Expensive.... that might not be entirely the case. For example yes the initial buy-in cost is more expensive... but in most all cases ( and depending if the lithium battery you buy has a full Battery Management System on-board) the battery will outlast the Lead Acid battery by twice the lifespan. The reasons for this first being an advanced Lithium battery has twice the rated cycles and more than a lead acid battery. Secondly, the advanced lithium battey has a BMS -Battery Management System that will not allow it to be over-discharged (the main cause of damage to any battery), over-charged, it also makes sure the cells are balanced when charging and discharging, it offers short circuit protections, and thermal protection so you get the longest life possible out of the battery. So,because the battery cannot really go outside it's set of defined parameters it has exceptionally long life and performance because it can't really be damaged by an accidental over-discharge like a lead acid battery. Then of course it has the massive weight-loss benefit... this may not be desirable to some but it is a definite positive factor when you can drop 35lbs just changing the battery in a car.

So when you combine all that, YES it more expensive initially but then pays for itself with a number of benefits... for example one time using our Built-In Wireless Jump Starting could save you money and the value of not being stranded is pretty significant. Do it two or three times and it has paid for itself because unlike the lead acid battery the lithium battery won't be damaged by the over-discharge because it will put itself to sleep.

Here's a link to the battery...we have different sizes to fit most all Performance Euro and American Cars.

https://shop.antigravitybatteries.co...tive/ag-h6-rs/

NickHolloman

Update, took the battery and had it tested. It was fine just a little drained from something pulling it down. Charged it up and threw it back in. Im thinking back now to a night a few weeks back when all my warning lights faded in and out on the dash and this is feeling more like an alternator.

De Jeeper

See my post #3. U need to check the alt and the wiring. There r known issues with the "y" wire to the starter. Do a search as there are alternatives to the factory wire that work better.

NickHolloman

Will do! thanks

NickHolloman

When I got home today I got the multi meter out and the batter was weak, only pulling 10.6V so it wasn’t enough to turn the car over.

Could the alternator cause that or does it seem like there’s a draw there? I disconnected the negative cable and it said it was drawing between 6.88 and 7.25 amps. I feel like that’s way high.

Porschetech3

Test charging system first..

Could be anything draining the battery ( even ignition switch not parking), but you can't test like that. Recharge the battery, crank and run engine, turn off, install in-line amp meter, without breaking connection,(20amp to 10ma). Takes up to an hour for all control units to go to sleep, usually 5-10 min. Battery drain should go down to about 30ma..

Dharn55

I bought a Bosch battery at Pepboys about 6 years ago which has a 36 months free replacement warranty. It seems that every 18 to 24 months it starts to not hold a charge as well. I take it to Pepboys, they test it, look at the date of manufacture and give me a new battery. I think I am on the third or fourth battery now. Kind of a pain but what the heck I change my oil much more often and have to pay for the oil and filter whereas the new batteries have been “free.” As long as they keep replacing the I’m happy.��

SeaBass8

I recently had to replace my battery in a pinch and went with the Walmart H6 Everstart Max. Cheap ($120) and convenient.

But tell me more about the "Know Issue" with the wires from the alternator to the starter? Every once in a while I get a no-start condition, I turn the key to start and no crank, reset the key and turn to start and it it will crank and start...Happens much less with the new battery. Maybe one out of 100 starts. Tiptronic. Also only seems to occur after warmed up. I was thinking ground or wiring connection issue somewhere along the line.

Anyone else?

2002C2

Seabass - any time that happens to me it’s because I didn’t get the clutch all the way to the floor.

peterp

It it was charged when you started the trip and low when you finished, it seems like the alternator is definitely not keeping up.

That current draw seems very, very high for parked -- was it still drawing that much later?

It seems unlikely that two things are bad (unexplained current draw and alternator/voltage regulator defective). Maybe the current draw is even higher when running so the alternator can't keep up, though it's difficult to imagine what could draw that much without any signs. Or maybe a higher sustained current load caused the alternator to wear out.

On the other hand, each battery cell puts out around 2.2 volts, so if you had a bad cell in the battery, it would probably drop you to around your 10.6 volt reading.

It definitely seems worthwhile to have an expert with the right equipment figure out what's going on.

NickHolloman

The battery is charging today on a trickle charge out of the car. When I get home today Ill test the battery before putting it back in and then test the alternator once its in and running. Im really hoping its the alternator but given that I cranked it with a fresh battery and pulled it out of the garage and back in then left it alone til the next day and it was dead makes me think Ive got a drain somehwere

peterp

In the old days, you could pull fuses one-by-one to find out where the current drain was, but I don't know if that is such a great idea for newer cars with ECU's. The only thing I can think of that would draw that many amps without any visible sign is the rear window defroster. The defroster should shut off with the key, but if the relay is stuck then maybe it would stay on. There rear window would be slightly warm if that is the case.

SeaBass8

Tiptronic, I updated my post but thank you for the suggestion.

peterp

Do you know whether it is a Bosch AGM or flooded cell type?