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Is this classic Alternator going bad scenario?

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4 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis

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YOUR RESEARCHIs this classic Alternator going bad scenario?

Leading reported evidence

Replace battery a month ago

Performed · outcome unconfirmed

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Unsuccessful attempts: 1
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Performed · outcome unconfirmed · Original poster
Changed battery a month ago.
Original post Read captured discussion
Is this classic Alternator going bad scenario?

Frequently discussed work

Replace based

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Reported fixes: 0
Unsuccessful attempts: 1
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Discussions that contain suggestions: 1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

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Suggestion
The voltmeter should show no change based on engine speed.
Original post Read captured discussion
Is this classic Alternator going bad scenario?

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Leading evidence: 'Replace battery a month ago' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Replace based' (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.

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Replace based

Suggestion or failed attempt

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Suggestion
The voltmeter should show no change based on engine speed.
Original post Read captured discussion
Is this classic Alternator going bad scenario?

Run correct

Suggestion or failed attempt

No successful repair reported for this finding.

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Unsuccessful attempts: 1
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Discussions that contain suggestions: 1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

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Suggestion
The battery reads 12V when engine is off and ~13.5V when the engine is running, correct?
Original post Read captured discussion
Is this classic Alternator going bad scenario?

Frequently discussed actions (3)

These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.

Replace based

No successful repair reported for this finding.

0
Reported fixes: 0
Unsuccessful attempts: 1
Discussions

Read evidence and context

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
The voltmeter should show no change based on engine speed.
Original post Read captured discussion
Is this classic Alternator going bad scenario?

Replace battery a month ago

No successful repair reported for this finding.

0
Reported fixes: 0
Unsuccessful attempts: 1
Discussions

Read evidence and context

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.

Performed · outcome unconfirmed · Original poster
Changed battery a month ago.
Original post Read captured discussion
Is this classic Alternator going bad scenario?

Run correct

No successful repair reported for this finding.

0
Reported fixes: 0
Unsuccessful attempts: 1
Discussions

Read evidence and context

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
The battery reads 12V when engine is off and ~13.5V when the engine is running, correct?
Original post Read captured discussion
Is this classic Alternator going bad scenario?

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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.

4 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.

1 acknowledgements have no verified action link; they do not establish a repair result.

Outcome without a verified action link
After doing the required search of the forums, I'm still not 100% sure that my alternator is bad, going bad, or something else.
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No unique explicit quoted action; no causal link assigned

Generation: 20261026T130754Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

Hi all - Long story short, I was out of the country for 6 months. Came back and the battery was dead. Changed battery a month ago. The volt meter on the car never registers 14V. 90% of the time, it is at 13V except right after starting the first time in a day, at which it read 13.5V (yeah, higher). Hard acceleration doesn't do squat to move the needle. A long drive (30+ miles) is followed by a slightly more hesitation in starting than usual. When the car is off but the key has been inserted, the voltmeter reads sometimes right at 12, sometimes slightly over, sometimes slightly under. After doing the required search of the forums, I'm still not 100% sure that my alternator is bad, going bad, or something else. The thing that bothers me the most is that the volt meter never, ever registers 14V. Unsure whether it used to do that before I went out of the country or not unfortunately. Will be doing a road trip from Chicago to Toronto soon in this car and rather not have any issues on the road, so question for the esteemed board: Is the alternator going bad? If so, I'm likley to take it to the Midwest Performance Cars. Any experience with them doing electrical work? Cheers, m.

POST 2Original post

So, you haven't been stranded correct? The battery reads 12V when engine is off and ~13.5V when the engine is running, correct? Sounds like everything is good to go.

POST 3 / ORIGINAL POSTEROriginal post

Hey, no haven't been stranded but I don't really drive the car that much lately. The volt meter reads 13V most of the time...the 13.5V reading is only after the first start of the day. Shouldn't it read 14V at least the time when accelerating? BTW, it is a 2001 996 C2. Thanks

POST 4Original post

The voltmeter should show no change based on engine speed. 13.5 volts is more than enough.

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