A battery needs 13.8 volts to initiate a good charging cycle. Average running voltage on my 6.0L was 14.2 volts. I'd suggest looking into another alternator or running a monitor to watch live output numbers (voltage meter) that are being run through the system. 9.8 volts is far too low, and cold starting a diesel with low voltage is hard on an engine and computer components.

 

When are you seeing the 9.8v? While starting the engine? When running? etc.

Ask because when fully charged, you should have 12.6 volts at the battery (key off). When cranking (cold), I will see my volts go to below 10 but after it starts, it will hover around 11 while the glow plugs are still on and then after a minute or so, my volts jump to upper 13s to 14+.

 

Mine does the same as well.

 

Repeated cranking with voltage starting/hanging in the 9's will fry your FICM as it tries to amplify voltage.

I ran top of the line batteries and never saw below 11.2V cranking. Of course plugging the truck in is what's allowing you to start the truck at all.

It's normal to see a dip into the low 10's high 9's in a normal situation after the glowplugs have cycled and the engine has cranked. What's not normal is to see an alternator not putting out enough voltage to initiate a deep charge cycle on a battery. Eventually the batteries will fail-they just aren't set up to handle this repeated situation.

 

The truck dropped to 9.8V on a cold crank, truck fired right up no problem, then was around 11 for a minute or two then climbed to about 13.4 i assume when the alternator started charging. I plan on getting a DC power alternator in the not to distant future, im wondering if i should get a charger on the batteries to move things along. Like i said these batteries are only a few months old, im going to double check all battery connections this afternoon...

 

Stop buying die easy batteries. Get Motor Craft or Interstate MTP-65. These trucks eat cheap batteries for breakfast. And good alternators do not come from major parts stores.

 

I had motorcrafts, and they last 12 months and 3 days and ford wouldnt warranty or honor anything... i wont run motorcraft batteries again, die hard used to be a great brand, dont know what happened there... But yeah i know the issues with alternators and chain stores, which is why i want a dc power alternator, its worth its 500 plus dollar tag with its lifetime warranty alone haha

 

I will check my batteries with a multimeter this afternoon and report back. Like i said above, a dc power alternator is in my future but i want to upgrade to a more powerful alternator as well as upgrade my wiring, just dont have the extra funds at the moment. I though i had some time because the alternator tested good... But i appreciate all input and will report back with my voltages. Thanks guys.

 

:rofl: Did the parts store test it?

If fords battery warranty and policy were better id buy them, but when you drop 300 bucks on batteries you kind of expect them to last longer than 12 months and 3 days... And no, my alternator wasnt bad, it was a brand new oem alternator, had it tested a few times and it tested good every time.

Find an Interstate dealer.

I do have one question regarding battery cable, i plan on upgrading to 0 gauge wire for positive and negative, can i do this with the current alternator or will the wire be to big for the oem alternator? I know undersized wire can cause problems but how about over sized wire? Sorry for my ignorance on this one but this isnt my strong suit...

No such thing.

This is interesting... I thought my alternator was bad for sure, as at points I was seeing less than 13V running with really no load. After a load test with a carbon pile load tester, I found that the displayed voltage on the CTS was about .5V less than actual voltage at the batteries. So when the CTS would show 13V the actual battery voltage on the load tester and volt meter showed about 13.5.

So... saved myself a few hundred bucks by testing the batteries and alternator with the proper load testing equipment and learned something new in the process.

Finally, someone who understands the concept of LOAD!!!!:drinking3:

 

I don't like MC batteries either, just didn't want to start a brand war. I run MTP65s and a 275 amp alternator.(from Nations starter and alternator) Lights don't even dim while plowing. I usually run them for 3 years and then put them in the 7.3 for 3 more years.

 

If fords battery warranty and policy were better id buy them, but when you drop 300 bucks on batteries you kind of expect them to last longer than 12 months and 3 days... And no, my alternator wasnt bad, it was a brand new oem alternator, had it tested a few times and it tested good every time.

 

I do have one question regarding battery cable, i plan on upgrading to 0 gauge wire for positive and negative, can i do this with the current alternator or will the wire be to big for the oem alternator? I know undersized wire can cause problems but how about over sized wire? Sorry for my ignorance on this one but this isnt my strong suit...

 

Have you looked into the big 3 mod.:nod:

 

I would say that your alternator is toast. In cold weather the PCM should command the alternator to put out it's maximum voltage. In warmer weather the PCM will command less voltage so as not to fry the batteries. Also if you are monitoring your voltage through the OBD port there is about a .2-.3 voltage loss than what would be read at the batteries. My next set of batteries will be from O'Reillys theirs are made by Deka which is made in the USA (Pennsylvania) and are not some crap from Mexico.

 

Also if you are monitoring your voltage through the OBD port there is about a .2-.3 voltage loss than what would be read at the batteries.

This is interesting... I thought my alternator was bad for sure, as at points I was seeing less than 13V running with really no load. After a load test with a carbon pile load tester, I found that the displayed voltage on the CTS was about .5V less than actual voltage at the batteries. So when the CTS would show 13V the actual battery voltage on the load tester and volt meter showed about 13.5.

So... saved myself a few hundred bucks by testing the batteries and alternator with the proper load testing equipment and learned something new in the process.