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my car coming to 3yrs old this August, the battery suddenly died. i had to send the car to services center for battery replacement. free. as under warranty. but the car stranded for 3 days in the service center.

the SA told me that the battery voltage fluctuate (with old and new battery) i really wonder why.

i have ME adapter installed. it have car battery voltage display. the apps only connect to ME adapter while engine running.

today i just realise, the battery fluctuate between 12.5v to 14.6v within minutes.

is this correct? or something wrong with my car.


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The alternator should put out a steady ~14V. A unit putting out 12V, even part of the time, is not enough to properly recharge the battery and run the vehicle's ancillaries under operation.
 

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12.5 is correct for a static battery (ignition on but alternator not operating). If the 12.5 reading was at start up you are probably OK. If you see that value in the midst of driving I would them be concerned about the charging system.
 

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12.5 is correct for a static battery (ignition on but alternator not operating). If the 12.5 reading was at start up you are probably OK. If you see that value in the midst of driving I would them be concerned about the charging system.
this is what i thought too, common sense.
i believe the SA is refusing to change it under warranty.

what i should do?

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First, does the voltage drop to mid 12 while you are driving? With all the draws on the battery like air conditioning and power steering let alone all of the electronics the alternator may not be able to reach charge rates at idle. If you are cruising at 2000 rpm and the voltage still does not reach charging levels, then I would be concerned.
 
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