Ok, the alternator is new, that's good feedback, so have a close look at the electrical connections to it, the battery cable connections on Both ends, to make sure all are clean bright & tight.
Make sure the serp belt tension alignment marks on the tensioner are within range.

If you have battery caps, check the electrolyte level without delay.

If the problem continues, run this puppy by your favorite auto parts store & ask for their electrical test guru to perform their no cost electrical system load test check up & see what the tester can find.

When you find a good quality smart charger on sale, consider coming by one, it'll more than likely pay for itself over its lifetime, has for me & we don't have to shell out large wads of our gold to come by a quality one either. Got mine for less than $30, it keeps my lawn & garden, vehicle & marine batteries nicely topped up at 2-6 amp charge rates.

My AC/Delco deep cycle trolling & cranking batteries bought by the previous owner back in the late 90's finally went belly up this spring. The other Walmart MAXX deep cycle was put in service by me in 04 & is still going.
I installed a 4amp per bank smart charger in the bass boat back in 01, to recharge the 2
deep cycle batteries as soon as I got off the water & put the boat to bed. I use a 2-6 amp portable smart charger to top up the cranking battery as needed. It's also used to keep the vehicle & lawn & garden batteries topped up as needed, makes those batteries last 8-10 years, if we don't let their charge get below about 70% & recharge Slowly, like they were discharged.

 

I checked all connections and all all are clean bright & tight. So far since the day I re seatted the fuses and checked all connections and driven to work and back home. The battery charge issue has not shown since. The re seating may have fixed the problem but time will tell and I will keep eyes peeled.

 

OK good feedback, maybe you got lucky on this one, let us know if the problem returns.

 

If the problem comes back I will post it up here. Thanks for all the help.

 

Well.........mine did it again yesterday. I wish it would just die......then I could find the problem. It won't ever act up long enough for me to start checking voltage on anything. Just makes me not be able to fully trust it................I will post anything I find........IF I ever can find anything...........Grrrrrrrrr

 

OK, well maybe its time to hook up your ELM scantool & have it be monitoring what's going on when the charging system acts out. It can take a snapshot when the anomaly occurs & maybe that will help focus where to more closely look for the problem.

If you don't have one, or would like to come by one, have a read through this thread & see if it may be an option you'd like to go for. https://www.ford-trucks.com/forums/1...-scantool.html
It's helped me find & fix ABS & power window problems.

 

Well, I finally determined that the alternator I had recently replaced was bad. Pisses me off when I put new parts on that are as bad as the old ones I took off!!!! The replacement alternator continued throwing its fit every now and then. Then it didn't act up at all for about 2 weeks. One morning I went out and fired the truck up and the light was on and voltmeter low. I throttled it up to about 3500 RPM and it all went back to normal. Stayed that way for about 10 miles then light came on. Pushed in the clutch revved it up to 3500, light went out all normal. So I began playing with it and it would react the same every time. Until, I went and started it the next morning, Light would go out above 3500 RPM but as soon as it returned to idle, came back on again. So.......pulled the alternator off and took it to OReileys and they put it on their machine........FAIL.........they gave me another one, same brand........ Bestest..........Hopefully I got a good one this time!!!! However that remains to be seen!!!!

 

OK, good feedback. Dang, a faulty New alternator!!!! I hope you had them bench test the replacement before leaving the store with it.
Over the years, if the store can do it, I've made it a habit to have them test all my electrical items before leaving with them, batteries too & I keep the test print outs if the test equipt provides it & staple it to the receipt which I also file with the vehicles records. A large ziplock bag is handy to keep all those things in one place for the record.
Anyway, good to hear you seem to have run this pesky problem down & got it put right.

 

No, I didn't have them test it. The thought entered my head, but was in a hurry. Hopefully this was an isolated issue, and not a problem with the whole batch. Time will tell. Not that it's that big of an issue to replace an alternator, but, it is a PITA when it happens!!! I hope Oreileys is not going to be like their predecessor Checker was waaaayyyyy back in the day. Seemed like you had to replace things 5 or 6 times to finally get a good part!!! Thanks for the input on this PawPaw!!!!

 

Roger on the bad batch/production run thought!!! We'll keep our fingers crossed that this was as you said an isolated issue!!!! Let the forum know if the problem returns.

 

Send them a bill for 2.5 hours @ $90 an hour labor, plus $15 for "shop supplies" and applicable sales tax.

 

Yeah, wouldn't that be sweet!!! Plus, $934,768.00 for "mental anguish".........LMAO

 

Don't forget "Loss of consortium."