A mechanic did a free battery test on my car battery and said it’s low on charge so I should get it replaced while saying the battery is probably not gonna die overnight, but should be replaced before winter. My battery was drained a lot about 4 months ago so it was struggling to start. This was …

@eddo : Thanks for your opinion, but how do you know the alternator is good when its output voltage is below the normal range of 13.8 to 14.8 volt? Plus another mechanic tested its voltage regulator to have failed which he said is the reason for low voltage output, and the responsible mechanic refus…

Ok, I went to one of those well known part store, and had them do a test on my new battery. Their reading was Good battery, voltage is 12.6 volt, measured 578 A (SAE), rated 600 A (SAE), temperature 114 F. The CCA on this battery is 600 so I think 578 is the amperage they measured which appears …

Those look like pretty good battery numbers to me. I concur with the test assessment, your battery is still ok. Summer vs winter? I’d guess the amperage output would be a little less in colder weather, and higher in summer. That’s why we usually see a lot of no-crank problems posted here in th…

Well, the #s are for the new battery I had put on Friday. So I’m getting 12.6V. However, with the engine running, I’m only getting about 13.5V. Could this be a sign my alternator is going bad? Alternator is only 10 months old. My understanding is you should be getting about 14.2 to 14.7V on th…

Stop driving yourself crazy checking voltage. Have the battery and alternator checked by a professional and you will have a real answer or just drive on.

Alternator voltage output can be 13.8-14.3 volts, depending on the engine RPM’s and the electrical load. Tester

Today, a mechanic A did a free alternator test, and said I have a alternator voltage regulator failure so it’s not fully charging the battery, and is charging the battery about 85%. Since the alternator is still under warranty, I went to a mechanic B who replaced my alternator, and he didn’t accep…

It sounds like you are looking for a problem that doesn’t exist. Why did you feel the need to test the new battery and alternator? Is there a problem with the car? This is the charging system test information from the service manual; Check the charging circuit. (1) Keep the engine speed at 2,000 …

Well, the alternator isn’t exactly new. It’s 10 months old. Battery is new. The car once stalled yesterday with check engine light on, and it seemed to have been ok after that, and today, I got all these tests done on the alternator with the #s I posted in this thread. So I changed the batte…

You can’t diagnose a bad alternator or regulator with a few voltage measurement. If you still have problems, take it to a place that can do a real load test on the alternator. If the car stalled out, and then restarted OK, it is not an alternator or regulator problem. Or battery problem. And when …

[image] Nevada_545: This is the charging system test information from the service manual; Which service manual? (I missed what this vehicle is.)

Can charging battery prolong its life

Maintenance/Repairs

BillRussell June 12, 2017, 10:37pm 33

Battery voltage/alternator voltage is only an indirect indication of battery or alternator status.

The voltage also depends on RPM, and the existing battery charge as well as other things.

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Can charging battery prolong its life

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