Battery won't stay charged, brand new alternator..

[goodtimejonny]

Hey,
I've got my '68 F-100, and the battery won't stay charged. I've replaced the alternator and also bought a new battery that same day.
I'm looking at the wiring diagram that I've found on this website. On my old alternator there were four wires coming out: one went
to the voltage regulator, one to the splice, one to the ground, and the other went nowhere. Does anyone know if that last wire could be
the issue? There is not enough power to start the truck, it will crank for a second if I try to start it. I can turn on the instrument panel lights though.
When I get the truck jumped, it starts right up, but, it will not hold a charge no matter how long I run the truck. I've gotten new batteries, and a brand new alternator,
the battery will never stay charged. I'm going to go take out that fourth wire to nowhere, and get it jumped to see if it will stay alive.
Otherwise, can anyone give me ideas as to what it would be?

Thanks,
Jon

[70shortwide]

it could be your regulator. ive had that problem several times. take a voltmeter to the battery while its running. should read somewhere between 12.6 and 14, i think. if its not charging it will probly be much lower than that.

to check the regulator unplug the connector for the regulator and run a jumper wire between the first and third positions.if your regulator is bad this will turn your alternator on at full steam, your shouldnt run it long this way as it can overcharge your system and cause more problems. check the voltage on the battery, it should read upwards of 12.6.
i may be a little off on the baseline (12.6) it may be a little more, but the results should be somewhat obvious
Hope this helps, if not im sure someone will be along shortly

[olgreen69]

If you tested the alt. And it checked out along with the regulator. You may want to check the amp draw from your starter.

[Jake11]

14.5 is normal. Ck the fuse links.

[Thunderfoot]

Hey,
On my old alternator there were four wires coming out: one went
to the voltage regulator, one to the splice, one to the ground, and the other went nowhere. Does anyone know if that last wire could be
the issue?

Yes, that 4th wire is an issue.
You should have 2 wires that go to the voltage regulator, one for the Stator wire and one for the Field wire. Then one wire for the power wire and one for ground…
Check out this diagram I modified to show the alternator wiring a little easier.

Stator wire = 4
Field wire = 35
Power wire (battery) = 38
Ground = 26

[70shortwide]

ive only got 3 on my alt. maybe mine is different? its newer, so maybe thats why but its only got three...

[Thunderfoot]

ive only got 3 on my alt. maybe mine is different? its newer, so maybe thats why but its only got three...

Do you know what 3 wires you have hooked up on yours? I've see the ground wire missing before without issues... The other thing would be if you have the 65amp alternator option with the external field relay like is in this diagram. http://www.fordification.com/images/sch ... arging.jpg but if goodtimejonny's has 4 wires there before, I imagine it is like what I posted above.

[70shortwide]

ok, mine isnt the original to my truck. it came with my 514. its big. i believe the wires that are hooked up are power, field and ground. i know power and ground for sure but its hard to see what the other one is, memory tells me its field. im fairly sure that this is irrelevant to his probem unless he has the same alt that i do. my camera isnt working right, i took the pics but cant get them onto the computer, sorry.

[goodtimejonny]

Hey everybody,
The problem ended up being the voltage regulator. I went and talked to the guy that I normally see when I've got troubles with my truck. He hooked up some machines and looked around. He found out that it was the regulator.
Thanks for the replies everyone.