Correct alternator voltage output?
Thread Starter
|
Senior User
Joined: Apr 2017
Posts: 153
Likes: 0
Correct alternator voltage output?
Hi I have a 1993 Ford F-250 with a 7.3 non-turbo. Today I decided I would check the alternator voltage output to see what it was. So I got my load tester which also tells me the charging voltage and tried hooking up those big clamps on the little stud on the back of the alternator. After a big spark (don't think I hurt anything) I quickly decided to use my volt meter. My volt meter was reading 13.68 volts that seemed a little low to me. The truck had been running at highway speed for about an hour and it was pretty hot out (90 degrees with high humidity). The truck has always started good just decided to check the alternator for the heck of it. Is this a good charging output for my alternator?
Senior User
Joined: May 2003
Posts: 138
Likes: 0
From: CT, USA
Yes. Anywhere between 13.2 to 14V is normall. a fully charged battery should be
around 2.1V / cell or 12.6 volts at rest.
You can also watch the dash voltmeter immediately after the truck starts. The meter should climb quickly a couple needle widths, indicating a voltage increase due to charging.
You can also watch the dash voltmeter immediately after the truck starts. The meter should climb quickly a couple needle widths, indicating a voltage increase due to charging.
i ain't rite
Joined: Mar 2005
Posts: 65,623
Likes: 5,634
From: Marlboro Mental Hospital.
12.5 volts with engine off, and 13 to 14.5 volts with engine running, depending on battery charge condition.
13.68 volts at idle tells me your battery is fully charged and alternator is working fine.
never hook to alternator to test, hook the load tester or meter to battery.
the large lug on the alternator will always read the same voltage as the battery as long as the wire is good.
13.68 volts at idle tells me your battery is fully charged and alternator is working fine.
never hook to alternator to test, hook the load tester or meter to battery.
the large lug on the alternator will always read the same voltage as the battery as long as the wire is good.
Posting Guru
Joined: Jan 2001
Posts: 1,101
Likes: 2
From: Poway, CA
If that is with all loads off, it sounds a bit low. See what it is with lights, radio, and the fan on. It's not THAT low, but even on my original alternator, with no load I would see low 14s and only 13.8 with everything on.
Then again, so long as it's pushing out more voltage than the batteries see at rest (about 12.5), you're fine.
Mike
Then again, so long as it's pushing out more voltage than the batteries see at rest (about 12.5), you're fine.
Mike
Thread
Thread Starter
Forum
Replies
Last Post
southern//magic
Ford Inline Six, 200, 250, 4.9L / 300
5
Dec 23, 2007 08:20 AM
