Alternator or battery problem?

[loboost]

Recently I've found my battery(ies) dead most every morning on my 2006 king ranch 250.

I jump it and it cranks with no issues. At idle I'm reading the alternator voltage ranging from 11.2 to 12.5 volts. At 1500-2000 rpm it pretty much levels out at 13.1 volts.

I'm measuring with a dmm on the post on the real of the alternator. There is a remanufactured decal on the unit so its been replaced at some point in time already. I'm fairly new to diesels and powerstrokes. Are these trucks known to eat alternators? Does this around like a battery problem or alternator?

I know it means nothing butvtge batteries are stamped 1/12. I didn't buy them, they were in the truck when I bought it. Thanks in advance.


I would like to add, that once jumped and running...I can let it idle at high idle up to operating temp and during the course of time it takes to load an sct tune, its dead again.

 

[FATHERFORD]

if you are only showing 11 volts from the alt the alt is bad.

 

[Lassie]

Get both batteries load tested first. A bad cell will kill your your alt's Volt reg too, so your alternator may be bad even if you find a bad battery. Parts stores will load test free.

And IMO, don't drive your truck until your battery problem is fixed. There is a chain of parts low voltage will destroy and it can get expensive....quick.

FICM is first concern...that can take injectors with it.

 

[97BambiBasherPSD]

What they said but I'm gonna assume its your alt. how old are the batteries?


Sent from my Pear phone using Tapatalk

 

[VanoFord]

sounds like you had a bad alternator that killed your batteries. the truck technically could remain running after starting even if you removed the batteries since the Alt powers everything when running. load test batteries, pull the alt and have it tested at the same time. good luck.

 

[sootie]

for 300.00 tops new batteries are cheap insurance as the elec circuit on the 6.0's are delicate. batteries are cheaper than injectors, ficm etc.

one of our 6.0's eats an alternator a year and has since new, we just count on it now and always have one in stock LOL

 

[VanoFord]

for 300.00 tops new batteries are cheap insurance as the elec circuit on the 6.0's are delicate. batteries are cheaper than injectors, ficm etc.

one of our 6.0's eats an alternator a year and has since new, we just count on it now and always have one in stock LOL

is this happening w/ the standard alternator, or have you all tried to upgrade to a HO Alt?

 

[loboost]

Thanks guys. I'll have them both tested.

For reference what should voltage output be at idle for a healthy system ?

 

[Lassie]

15 or more after crank or other high draw. Should settle to around mid 13

 

[loboost]

15 or more after crank or other high draw. Should settle to around mid 13

Is there any delay before it will begin charging @ full capacity? I have noticed that mine will register at like...10.5-10.9 volts until it runs a few minutes

 

[Fordguy100]

Low alternator output can be because the batteries are so drained, that's it's struggling to charge them. The Ex can't sit more than a week without running before te batteries drain down. If the barreled drain down to below 12v with the engine off, it takes a looooong time to idle/run to get them into good enough shape to hold 13v at idle.

Load test batteries, have them test alternator. After that, figure out if your truck has a draw. I know mine does, just gotta take the time to figure out why/where

 

[Lassie]

No delay...It should read highest after crank.

 

[loboost]

No delay...It should read highest after crank.

Yea I'm reading like 10.xx for the first few minutes lol

 

[Fordguy100]

The terminal on the alternator should read right around what the battery voltage is. A cold start on drained batteries will mean a low reading at the alternator. The alternator has a hot right to the batteries, there should never be a big difference between the two, if so something is goofy.

At least thats what I would think...

 

[Fordguy100]

Yea I'm reading like 10.xx for the first few minutes lol

Drive it for 20 miles. What is the voltage while driving? Stop, shut truck off, what is the battery voltage sitting? Start it up. What is the voltage after 10-20 seconds of idling after that drive?

Its reading low for that long because the alternator is having a tough time charging the batteries back up to where they should be, taking up all the amps the alternator can put out. The stock alternators are dinky little 110amp things (my VW TDI has a 120amp alternator!!)

 

[Buellstunter]

I have a slight delay as well from my alternator. My Edge cts displays batt. voltage at 11.9-12.2v before starting with key on. Start truck and let it idle, it stays about 12.5v and then within about 15-30 sec. goes to 13.5-13.7v. I just replaced the alt. with a 135Amper, and batt's are only about 7months old.. I took the alt. back 2 times now and had it tested because my idiot light in the dash keeps coming on. but when the light comes on the voltage never drops below 13.3-13.5 volts. not sure why the light keeps coming on, but everything else seems ok even with the delay..