32 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHDead....dead...dead
Leading reported evidence
Replace battery last week too
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Leading evidence: 'Replace battery last week too' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check battery health' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
There are better ways of checking battery health that will catch more modes of failure, but you unfortunately need some special tools to do it.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
Properly charged, the batteries should sit 12.5-12.7V or so, up to 13V if you check right after charging.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion · Original poster
Thanks, looks the like 86's battery is toast as well....wont take a change The Phil Battery curse!
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
32 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261026T112012Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Went to fire up the 996 today, over 50 and sunny!
Battery was ...dead. Battery maintainer was ...dead.... (battery was 4 years old so thats ok)
New battery.... new charger.
Maintainer on the 86 does not seem to be working as well, do these things have a shelf life?
It was an action packed day, Set up a surround sound system for a friend, an hour of playing ball with the dog, playing with my daughter, Battery fun with the cars and fixed a few things around the house.
I'm shot....
Tomorrow there is a drive planned with the Ferrari guys but I am going to miss it and hang with the wife/kid/dog.
Next week our "Cars and Croissants" meets start again so thats why I am getting the cars ready to play again and since the weather is nice I want to start driving the 996 to work.
If I have time tomorrow I will install my 997 Airbox..... shiny parts!
next week is another track day... not sure if I will go yet.... (yea right)
tomorrow will be house stuff day I guess.....
still sorry about the battery issue - Phil should be by soon to offer his words to you
A battery has a life rating in 12 month periods. A number like 36, 48 or 60 means 3, 4 or 5 years life span. Once the acid solution is put in the battery the timer starts on how long it takes the acid to burn through the plates coating. You can bet the technology of plating the battery so that the acid burns through right near the life span rating is spot on.
It's a little more complicated than this. The chemistry is faster at temperatures above 77F; every 15F above that will half the battery life; sitting under a hood baking at 140F for a few hours a day is not the best thing to do for longevity. The biggest problem with winter storage is sulfation and overcharging. If you just let a battery sit, sulfation will form on the plates at voltages below 12.5V, which simultaneously erodes and insulates the plates. If it hasn't entirely insulated the plates, it will all dissolve back into solution at voltages above 12.5, but the repeated cycles damage the fragile high-surface-area pattern on the plates and reduce cranking amps. Even worse is overcharging; overcharging drives off hydrogen, and ruins batteries in a hurry; you can't top off an AGM battery, if it's overcharged, it's permanently damaged.
Makers sell different warranties on their batteries, but I'm not convinced it's not 100% marketing BS, and I have a feeling if you crack the cases, the batteries are absolutely identical inside. Even supposed "10 year" batteries only last 3-5 years. Sometimes, they just outright fail. Sometimes a cell will short out and output will drop 2V. AGM tend to fail open and just suddenly stop working. Towards the end of a battery's life, even if it's still working, the waffle pattern on the plates is gone, hydrogen has been driven off, and it's just not going to be able to put out the amps it could when it was new. Especially not when it's cold out and all the battery chemistry is at its most inefficient at the same time the engine oil's very cold and been sitting for 6 months. So, yeah, that's when you'll most often see failures.
Somehow I can't see paying the price for AGM anyway, unless you are worried about weight. I (not really on purpose) put a huge regular plate battery in that completely fills the tray. Had to modify the clamping to get it to fit. Understeer here we come!
Automotive starter batteries are delicate things; they have thin plates with fine patterns to maximize surface area to give you maximum cranking amps. Every time you discharge your battery, some of the lead is dissolved into the electrolyte. Every time you recharge, it's redeposited on the plates, but not necessarily back in the same spot. Eventually, the plate loses surface area, and tiny pieces break off and settle to the bottom of the battery, and can short out the plates. Better batteries have thicker plates that are more resilient, but can only do this to a point.
Deep cycle marine batteries have thick flat plates and can withstand hundreds of deep cycles without significant loss in power or life. If you tried to start your car with one, it wouldn't work, though- the plain flat plates can't put out the cranking amps a car battery can.
Most cars, I just drive it until it dies or at least shows signs of imminent death, but I'm rather paranoid with my 986, what with not being able to open the hood to even jump-start. (Yeah, I know about the terminal block.)
My OEM battery made it about 5 years, but was clearly near the end-of-life. Properly charged, the batteries should sit 12.5-12.7V or so, up to 13V if you check right after charging. Never below 12.5V for any length of time, as that will cause sulfation to form. I knew my battery was old and checked it regularly, watching it drop steadily; after it started dipping into the 11.xV range after just 3 days of not driving, I knew it was time to stop waiting, and yanked it.
There are better ways of checking battery health that will catch more modes of failure, but you unfortunately need some special tools to do it.
This is a source reference. Confirm exact model applicability in the original material.
