911uk

Battery voltage and potential replacement

Add to repair workspace

New repair projectOpen repair workspace

Original source

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

THIS DISCUSSION / SOURCE-DERIVED OVERVIEW

Discussion summary

YOUR RESEARCHBattery voltage and potential replacement

Leading reported evidence

Check which cant be done if the battery is sealed

Suggestion or failed attempt

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 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 only other check would be a dedicated battery tester or an acid check which cant be done if the battery is sealed .
Original post Read captured discussion
Battery voltage and potential replacement

Read full discussion summary

Leading evidence: 'Check which cant be done if the battery is sealed' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check which cant be done if the battery is sealed' (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.

Read captured replies

1 matching discussions · 4 captured posts examined · 0 partial discussions

Compare 4 other evidence results

Check would be a dedicated battery tester or an acid

Suggestion or failed attempt

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 only other check would be a dedicated battery tester or an acid check which cant be done if the battery is sealed .
Original post Read captured discussion
Battery voltage and potential replacement

Replace '

Suggestion or failed attempt

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 · Original poster
The description in the manual is 'tests if the battery can hold charge, checks if voltage drops to 12v, batteries that cannot hold charge may need to be replaced'.
Original post Read captured discussion
Battery voltage and potential replacement

Replace ahead of

Suggestion or failed attempt

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 · Original poster
At the same time, I want to avoid the hassle that seems to go with a completely flat battery so would rather replace ahead of that.
Original post Read captured discussion
Battery voltage and potential replacement

Test /had the battery

Suggestion or failed attempt

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
Have you tested/had the battery tested properly rather than rely on the charger?
Original post Read captured discussion
Battery voltage and potential replacement

Frequently discussed actions (6)

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

Check which cant be done if the battery is sealed

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 only other check would be a dedicated battery tester or an acid check which cant be done if the battery is sealed .
Original post Read captured discussion
Battery voltage and potential replacement

Check would be a dedicated battery tester or an acid

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 only other check would be a dedicated battery tester or an acid check which cant be done if the battery is sealed .
Original post Read captured discussion
Battery voltage and potential replacement

Replace '

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 · Original poster
The description in the manual is 'tests if the battery can hold charge, checks if voltage drops to 12v, batteries that cannot hold charge may need to be replaced'.
Original post Read captured discussion
Battery voltage and potential replacement

Replace ahead of

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 · Original poster
At the same time, I want to avoid the hassle that seems to go with a completely flat battery so would rather replace ahead of that.
Original post Read captured discussion
Battery voltage and potential replacement

Test /had the battery

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
Have you tested/had the battery tested properly rather than rely on the charger?
Original post Read captured discussion
Battery voltage and potential replacement

Test properly rather than rely

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
Have you tested/had the battery tested properly rather than rely on the charger?
Original post Read captured discussion
Battery voltage and potential replacement

Coverage and how to read this overview

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.

911uk: 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: 20261026T183130Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

Hi, If I know I'm not going to drive my 3.4 for a week or so then I plug it into a CTEK MXS 5.0. Recently when I do this, the CTEK will intermediately stop at stage 5. The description in the manual is 'tests if the battery can hold charge, checks if voltage drops to 12v, batteries that cannot hold charge may need to be replaced'. It doesn't do it every time but often enough to conclude that the battery isn't holding charge. The question is, how low can the voltage go and the battery still operate fine? I drove it on Monday and it seemed to start fine. Just wondering if I need to replace right away or just do it as soon as it becomes slow to turn over. At the same time, I want to avoid the hassle that seems to go with a completely flat battery so would rather replace ahead of that. Thanks

POST 2Original post

Have you tested/had the battery tested properly rather than rely on the charger? I would do that before buying a replacement.

POST 3 / ORIGINAL POSTEROriginal post

Thanks, just put a volt meter on it. It's showing about 12.5 normally, just over 14 when running (so I guess the alternator is fine) and it drops to about 10.5 when I start the engine. I'm not sure how low it should go when I start, I know lower single figures is bad but is over 10 fine? Thanks

POST 4Original post

10.5 volts on cranking is what a good battery should read . 14 volts running is fine but you really need to have a voltmeter on the battery .. turn lights and any heavy electrical loads on then see what it is at idle .. anything less then 13 volts and your into a worn alternator. 12.5 volts is again a sign of a good battery . The only other check would be a dedicated battery tester or an acid check which cant be done if the battery is sealed . If the battery starts the car after 4-5 days without being used in the mean time or connected to a charger then its fine.

This is a source reference. Confirm exact model applicability in the original material.