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did a quick test. with the engine running, I checked the voltage of the battery with a volmeter, it read 14.05. I read online that if it's under 14.2, then it means alternator is not working at its best. Is this true?
Location: East of Seattle since 1992, 615' Elevation, Zone 8b - originally from SF Bay Area
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Normal is 13.8-14.2, but different web sites may have different number, and it varies by RPMs and what accessories are running. I wouldn't worry about it unless you are having trouble cranking. I have only had one ever go out, and that was a 1990 Bronco with 130,000 miles.
Normal is 13.8-14.2, but different web sites may have different number, and it varies by RPMs and what accessories are running. I wouldn't worry about it unless you are having trouble cranking. I have only had one ever go out, and that was a 1990 Bronco with 130,000 miles.
I have had 3 quit.
The last one, the original lasted 19 years.
Older cars had no warning.
Newer cars have a light on dash that comes on as a warning.
You can connect your volt meter right to the hot bolt coming off he alt and see what it reads. It could be corroded wires creating some resistance although .1v probably isn't a big deal.
did a quick test. with the engine running, I checked the voltage of the battery with a volmeter, it read 14.05. I read online that if it's under 14.2, then it means alternator is not working at its best. Is this true?
Battery is less than 1 yr old.
thanks.
Not an good way to test. Take car to local parts store and ask if they can test your charging system on the car.
The mere fact that the engine is running [dist., spark plugs, clock] causes power to be drawn from the battery. If you leave the volt meter on the battery long enough, you will see the volts drop to around 12.6 The voltage regulator would then allow a 'charge' from the alternator to bring the battery back to 14v The cycle works faster when the radio, headlights, A/C fan, engine fan, windshield wipers are on.
The voltage regulator will fail before the alternator fails.
The mere fact that the engine is running [dist., spark plugs, clock] causes power to be drawn from the battery. If you leave the volt meter on the battery long enough, you will see the volts drop to around 12.6 The voltage regulator would then allow a 'charge' from the alternator to bring the battery back to 14v The cycle works faster when the radio, headlights, A/C fan, engine fan, windshield wipers are on.
The voltage regulator will fail before the alternator fails.
That is not how a charging system normally works. Not at all.
^^^^^
Absolutely and totally how the battery gets charged and the reason why the alternator has an internal voltage regulator.
The voltage regulator attempts to keep the alternator output steady. It will only drop down to 12.6 or so if the electrical load exceeds the alternator's capacity and particularly if the engine rpm is at a slow idle. The description of the hunting between 14.0 and 12.6 volts is not accurate.
Charging systems are also temperature regulated and the alternator output voltage will be slightly higher in colder temperatures.
Don in Austin
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