Got the batteries back in and the alternator hooked up. Unhooked all my accessories (gauges, heated mirrors, amp/sub, cb radio, brake controller, etc - most were wired to a secondary fuse panel so it was only one wire to pull) Been driving the truck for a few days and all seems ok, I'll start hooking accessories back up when I get the time to check them out one by one

 

As I said before I've been driving the truck with everything unhooked, so far so good until this morning - battery light came on (with some flickering) when I pulled out of the driveway to go to work, seemed to only be on when I was on the accelerator (would go of if I let off and coasted). Turned off after a few miles....what should I check now?

 

Check the charge output cable and connector (under the boot) at the alternator. I had a flickering batt light. Fix was to strip that cable back to some clean copper and put on a new connector. Bad connection there also causes the charge cable to get extremely hot. May also cause heat build up in alternator.

 

Interesting, the boot cover was black and brittle - actually broke off when I disconnected the alternator when this all started...possibly from heat? I'll try to look at that connection tonight, not sure if I have a ring terminal that size though...

 

That's just what I found.

I got a crimp on battery cable lug at O'Reilly's.

Some Noalox on the exposed wire and crimped twice.

A second charge cable directly from alt to driver side batt is next.

Instead of the boot I used two layers of shrink tubing. This will
also allow me to keep an eye on that connection.

 

if you think your alt is going bad and killing the batteries, you can check it by feeling the alt when the truck is cold before you start it in the morning, and see if it is warm, if it is warm it is bad. The field coils stay active some times when they are bad and it will kill the batteries really fast.

as a side note since, on my 2000 7.3 X, the lights flicker inside when the head lights are on at night when the doors are open. Is that the voltage regulator or the rectifiers in the alternator going out that causes this? It is charging fine and I have had no starting issues with this vehicle at all in the 5 months I have owned it.

we now return you to your regularly scheduled thread....

 

The solder used to solder the stator windings to the diode pack isn't always a high-enough temperature alloy to prevent it from getting "plastic" (or semi-melting) when there are extended periods of high current flow. Combine that with the vibration of sitting on top of a running diesel engine, and you have a situation where internal arcing can begin, which isn't easy on the diodes. Inferior solder is most-often found on second-source (offshore) units.

That arcing can cause semiconductor failure, and if a diode shorts, there is constant current flow through a stator winding, causing the heat mentioned in the post above. The shorted diode, thus constant current flow, reduces the amount of charging an alternator can do, and is what flattens a battery overnight, too.

If the low-budget, high-profit "lifetime guarantee" units simply had their winding solder points "touched-up" with high-temp solder during the rebuild process, they could be more reliable. But that takes labor and cuts into profits.

If the offshore units used high-temp solder to begin with, they might be more reliable, too.

Damn bean-counters, anyway....................

Pop

 

I dont think this is the case...when my batteries went dead I had the hot lead to the alt. disconnected. Truck was just sitting there parked. I've got tomorrow off so changing out the end of that cable is on my list of things to do.

 

UPDATE: still trying to figure this issue out, still running with no accessories connected - I recently bought one of these ( ) so I could see what was going on while driving, the highest voltage I've seen is 14.3 with it generally holding steady around 14.05 - but at seemingly random times it will just drop off, down to the 10 or 11 range and my battery light will flicker at the same time, beginning to suspect I may have something going out in the alternator....?

 

Issue seems to be getting worse (voltage stays lower for longer periods of time), I seem to be able to effect the output - bring it back to a charging condition - if I play with the rpms or apply the brake

Had the alternator checked at O'Reillys and Carquest today, it tested good on both machines.

I was going to replace the connector for something else to try but no one seems to carry the right harness - I ordered one (PartsMaster 84016 - Interchange: Dorman/Conduct-Tite 85843, SMP S545, Ford 1U2Z14S411UA) but it is a bigger plug and has 3 wires instead of 2. Any idea what part # I need?

Short of the changing the plug I'm stuck....what am I missing here?

 

If you're getting a flashing battery light check the brushes as well as checking the slip ring (the round copper piece at the back end of the rotor. Some shops love to just cut these instead of using new ones, which results in them being cut too thin and the brushes can eat through the copper. Both of these will cause a flashing battery light, and they will get worse over time.

 

Could be the field brushes reaching end-of-life.

They tend to get intermittent before they go completely away.

Pop

 

So that would explain why it could still test good....

Anything else in the circuit that I should be looking at?

 

If you're adventurous, why not pop off the alternator and take the back off so you can SEE the brush length and feel the spring tension on them

It's not rocket science. I know that because even I can do it.



Who knows, if the slip rings aren't grooved and worn, all you may need is a new regulator.

See this as an example:
http://www.ebay.com/itm/ALTERNATOR-R...8ebcc9&vxp=mtr

Pop

 

Yes, that would be exactly why it would still test good. Not to mention the average parts store's test equipment isn't exactly comprehensive.

As Pop said, if it's just the brushes you can get away with just replacing the regulator/brush holder assembly.