Can someone tell me the symptoms you should see with low batteries? Please include least severe symptoms and worst case scenario.

Thanks,

Mike

 

Why ask this? Why not simply test the battery voltage engine off (12.5v), battery voltage engine running ( right after start, about 13.8-14.4). This shows alternator works.

Have some else start the vehicle and watch battery voltage.... it should drop to about 11.5-12v.

Severe symptoms is no start. FICM voltage also low (possibly causing the no start).

 

I've been having some missing, studdering, and most recently bluish/gray smoke issues and can't seem to find the problem even using AE. So, I asked the question so I could see the range of issues that low batteries cause so I could track it along with how my truck has been acting the last couple of months.

At lunch today:

KOEO - 11.5 V
During Cranking - 10.6 V
Before glow plugs quit - 11.1-11.2 V
After glow plugs quit - 13.9 - 14.2 V

Batteries were load tested two days ago at O-Reilly's. Both tested "GOOD".

 

If you want an accurate diagnosis you need to charge both batteries and load test them seperately. Battery voltage after sitting overnight with the key off should be 12.5 min. and optimally 12.7.

 

Does it matter if the truck is plugged in or not?

 

I don't see where that should affect the batteries. Assuming you meant the block heater.

 

My truck ran perfectly with one failed battery and one marginal battery. It barely cranked enough to start, but once it did, it ran fine. That was at high altitude on a cold mountain.

Those values look normal to me.

 

I was having some slow starting issues on my '06. The Scangage 2 showed that battery voltage dropped to 10.5 volts when cranking the engine in cold weather. Definite battery issue.

Two new Morocraft 850CCA batteries were installed and all of the slow cranking problems are history. Two days ago it was 4 deg F outside. The truck started and ran just fine. The truck was not plugged in.

Batteries in these trucks take a beating. Very probably some of hte starting-running problems that we see are battery related. The expert technicians here would have a better idea about how weak/old batteries affect our trucks.

Lou Braun

 

Your Battery light on the dash is Very accurite you could say its an Idoit light with a PHD if its not coming on or flickering your batterys and charging system is more than likely OK

it does help to clean all Battery terminals and conections and grounds even the Block and Frame Grounds off each Battery this will help save your charging system and batterys in the Long run

 

Benny do you think low batteries would have anything to do with my issues? Going to check voltages tomorrow morning first thing. Will post my results.

 

Your issues sound more like the FICM than batteries......go here for test procedures: https://www.ford-trucks.com/forums/8...procedure.html

 

I've tested the FICM.

This is when cold after overnight - outside temp 7 degrees. Block heater plugged in...

KOEO - 48.5-49
During Cranking - 48.5
While Running Cold - 48.5
While Running Cold at 2000 RPM - 47.5-48.5
While Running at Operating Temperature - 48.5-49

 

Battery Volts this AM after truck sitting overnight

KOEO - 10.6
During Cranking - 10.6
Immediately after start - 11.4
After alt. kick-in - 14.2

 

The 10.6 KOEO is a little low. But remember you've got glow plugs on at this point. However once it starts you're getting good voltage, so that is not the problem with the running problems you are experiencing.

 

I started a new post this morning regarding a new issue. You may have read it already. The 'CHECK GAUGES' light came on this moring about 10 times in the last 1/2 mile drive to work. Everytime the light came on the stock oil gauge would drop all the way down until the 'CHECK GAUGES' light went off. I'm thinking this has to be related to my running issues. Benny said to check ICP and IPR when this happens. I will do so over lunch if it happens again.