Battery Question
Elder User
Joined: Jan 2007
Posts: 612
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No if one of the cells is dead the voltage would read lower then normal. The reason why the battery reads that high is because either the truck was just running and you took a measurement and you are reading the floating voltage and/ or the battery is cold. Cold batteries have higher floating voltages. If you want to take a true measurement let the vehicle sit in a warm garage for two hours then read it.
Dont worry about that reading. It does not indicate anything is wrong.
Dont worry about that reading. It does not indicate anything is wrong.
Thread Starter
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Posting Guru
Joined: Jun 2004
Posts: 2,058
Likes: 2
From: Cookstown
well i replaced the battery anyways. but now I just started the truck and let it run for a while with the alternator removed and the voltage in the battery just keeps climbing. Now it's up to 19.4V
Jim
Jim
Moderator
Joined: Jan 2001
Posts: 57,014
Likes: 2,751
From: Virginia
Do not run the truck with the alternator disconnected. It is possible to ruin the electronics. With everything connected, and the truck at idle, you should have around 14.5 volts on the battery.
Take the reading this way, and see what you get. That will give you a better health report on your charging system.
Take the reading this way, and see what you get. That will give you a better health report on your charging system.
Elder User
Joined: Jan 2007
Posts: 612
Likes: 0
Originally Posted by taisa899
well i replaced the battery anyways. but now I just started the truck and let it run for a while with the alternator removed and the voltage in the battery just keeps climbing. Now it's up to 19.4V
Jim
Jim
Its not physically possible for a 12 volt battery to reach that high of a voltage without an alternator or other charging device. So get a different multimeter and try. Your metering the batteries voltage not the alternators when you had the alternator disconnected right? Regardless of a batteries state the voltage cannot increase much beyond 12.6 volts without any charge on it and with no floating voltage on it. Its a matter of physics. The cells in a 12 volt lead acid battery are about 2.1 volts each fully charged. The battery has six of them. With all six you get 12.6 volts. A damaged or defective battery can will show abnormally low voltage but it cannot show abnormally high voltage.
Last edited by SPL Tech; Feb 2, 2007 at 12:06 AM.
