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What volts should an alternator charge a battery at??

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Old 06-04-2011, 11:57 AM
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TIFF
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Default What volts should an alternator charge a battery at??

I just want to eliminate my alternator from playing up as its charging my car at 13.6v........
Old 06-04-2011, 12:02 PM
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Psycho Warren
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thats fine on light/medium load.

whats it charge at with all the lights on, blower fan on etc.

should still be about 13V ish.
Old 06-04-2011, 12:03 PM
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not sure, never loaded it up tbh.............

You say it should be over 13v loaded up?
Old 06-04-2011, 12:28 PM
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pani_k
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Front quick clear screen on in the focus and rear screen on in the winter from cold shows about 13ish on the volt gauge I got in the car with an under driven alternator. Usually charges around 14-14.5V at 2000rpm or so.
Old 06-04-2011, 12:38 PM
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I get about the same, with no load and with a heavy load I get 13V, I posted a similar thread as some get different reading, so long as it's charge is greater than the open circuit of the battery I.E 13V+ your ok.

Focus is different as that has "Smart Charge" these charge higher, sometimes around 15V+, when I tested mine with heated screen etc it maintained 14.2V.

Martin
Old 06-04-2011, 01:31 PM
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14.7 Volts
Old 06-04-2011, 02:31 PM
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Rod-Tarry
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A modern automobile has a 12 volt electrical system. A fully charged battery will read about 12.5 volts when the engine is not running. When the engine is running, the charging system takes over so that the voltmeter will read 14 to 14.5 volts and should stay there unless there is a heavy load on the electrical system such as wipers, lights, heater and rear defogger all operating together while the engine is idling at which time the voltage may drop. If the voltage drops below 12.5, it means that the battery is providing some of the current. You may notice that your dash lights dim at this point. If this happens for an extended period, the battery will run down and may not have enough of a charge to start the car after shutting it off. This should never happen with a healthy charging system because as soon as you step on the gas, the charging system will recharge the battery. If the voltage is constantly below 14 volts, you should have the system checked. If the voltage ever goes above 15 volts, there is a problem with the voltage regulator. Have the system checked as soon as possible as this "overcharging" condition can cause damage to your electrical system

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Old 06-04-2011, 02:32 PM
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13.2 -14.7 is the range to look for, anywhere in between is fine.
Old 06-04-2011, 08:12 PM
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tabetha
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Originally Posted by MadRod
A modern automobile has a 12 volt electrical system. A fully charged battery will read about 12.5 volts when the engine is not running. When the engine is running, the charging system takes over so that the voltmeter will read 14 to 14.5 volts and should stay there unless there is a heavy load on the electrical system such as wipers, lights, heater and rear defogger all operating together while the engine is idling at which time the voltage may drop. If the voltage drops below 12.5, it means that the battery is providing some of the current. You may notice that your dash lights dim at this point. If this happens for an extended period, the battery will run down and may not have enough of a charge to start the car after shutting it off. This should never happen with a healthy charging system because as soon as you step on the gas, the charging system will recharge the battery. If the voltage is constantly below 14 volts, you should have the system checked. If the voltage ever goes above 15 volts, there is a problem with the voltage regulator. Have the system checked as soon as possible as this "overcharging" condition can cause damage to your electrical system
Not quite, a lot depends on battery TYPE, std lead/acid and lead/calcium that are fitted mostly are fine at up to and not a jot over 14.4V , otherwise excessive gassing will occur, as a rule anything from 12.4 -13.4 is fine with no load and idle, with a big load, so long as it maintains around 12.8 or over that is fine, for the above battery types.
We then have FULL calcium,(most calcium are mixed lead/calcium) which can charge at up to 16 volts and is normal for them, a calcium battery can operate perfectly in place of a std lead/acid battery, but a lead acid in place of a std calcium can go bang.
tabetha
Old 06-04-2011, 09:13 PM
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So the verdict is 13.6v on idle should be putting a charge into the battery???
Old 07-04-2011, 06:19 AM
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yes. have you had the battery tested?
Old 07-04-2011, 08:01 AM
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In what way tested????....
Old 07-04-2011, 09:17 AM
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Drop testing is nice and easy, but possibly not diy-able
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