Could someone with a 07 5.4l read their battery voltage with a meter while the truck is shut off and post what it is? My truck is reading 12.3V but every other vehicle I have tested reads a steady 12.6V. I am trying to figure if this is specific to new Fords, my truck, or I have a bad battery.



Thanks

William

 

12.6 is a battery charged 100%. your sitting around 60% right now. it may need a good trickle charge or the battery may need to be replaced.

 

could someone post a actual voltage reading frmo their truck? looking for a reading from a 07 5.4l

Readings from multiple guys would be great that way I can get a baseline for different trucks out there!

 

Trust me, I've been at this for a long time. The guy that told you that 12.6 was full charge was spot on. You do realize that in order to get an accurate reading you have to do a load test. (fully charge and then do a load test) With a simple volt meter you are reading the surface charge (which does you no good), you have to read it after the surface charge is removed. It doesn't matter if the whole world is showing 12.3v, that is still only about half charged. Either it is partially run down or is going bad. When a battery goes bad it seldom wakes up one morning and decides it'll go bad that day. It goes bad over a period of time and the nature of 12v is that you can't NORMALLY tell it like you could on 6v. If you are doing regular load tests, you will see that decline in the tests over a period of time. Motorcraft batteries used to be made for many years by GNB (Gould National Battery), and was one of the best batteries in the business. About 4 or 5 years ago they sold to Excide and now are pretty much junk like everybody elses. The Gould's most of the time tested 12.8 when fully charged but that is pretty much history. 12.6 is you magic #- forget what the entire rest of the world's are testing- it has no bearing on what is charged and what is not. This isn't an election- it's a battery test.LOL

 

Trust me, I completely understand the voltage is supposed to be 12.6 however my 07 5.4l will report 12.4 shortly after shutdown. I am trying to figure if this is normal for F150s or just my truck.

 

.2 or .3 volts different ain't nothing to lose sleep over, nor is static voltage an accurate means of determining a battery's condition.

 

The static voltage will tell you if you have a dead cell, but the voltage would be in the 10v range if that were the case.

Since you did ask, however, I will quench your curiousity. On my '07, the voltage at the battery is 12.51 right now.

 

So, say a vehicle was run for a little while with a faulty alternator, it was running straight off the battery, and it ran until it quit, until there wasn't enough electrical power to keep the PCM running. That's typically around 8-9V, depending on the vehicle; that doesn't mean that the battery is bad, nor does it mean that a cell is bad, just that the battery is discharged. Assuming that the A/C ripple from the alternator wasn't too excessive, that battery could be recharged and brought back to life.

Conversely, in a company car I drove last week, the battery read 12.6V exactly across the terminals, but failed to start the engine. That 12.6 dropped to about 1.5V while trying to start (granted, not a very accurate load test, but it was the best I could do at the house).

Static voltage is not an accurate means of determining the battery's state of charge. It's about as accurate as the eye on the top of the battery case.

 

I will be more clear in my response.

The static voltage will indicate if a cell is dead IF the battery has been charged. If, after charging, the voltage is still in the 10v area, it has a dead cell.

I agree with your other situations -- a perfectly good battery may drop into the 10's, indicating it needs to be re-charged.

In the end, his voltage of 12.4 is fine.

 

Quintin- Have tested many a battery and 1 day when I was near where they stored the junk batteries to be picked up, I spotted a Motorcraft (aftermarket) that didn't even have any dust on it. I worked for a major county transportation division and they used so many batteries that sadly they didn't ever warrantee a battery if it was new because they didn't have time to try and keep track of the documentation for warrantee- easier just to junk it and forget about it. I took the battery and charged it and tested it. I use a OTC Accuracy Plus Professional tester. It tested it and it tested like new. Was a heavy duty- I believe 950 or 975 CCA. I have a habit of retesting the next day if the car or battery is still around. I just figured the mechanics had thrown a new battery at the car without properly figuring out what the problem was. Next day the battery tested bad. Scratched my head and recharged it again. Once again tested like new ( at least rating or better). Next day tested bad again. Every time i would charge and test it would show strong under even repeated testing. Next day would test bad. I guess maybe the mechanics did their job. (they were pretty notorious for throwing batteries at cars without finding what the drain was). Have you ever encountered anything like this? I mean this battery tested STRONG but just couldn't hold it.

 

12.6 is correct as we told you in the other thread. The majority of batteries are made up of 6 cells of about 2.1 volts. If you lose a cell your voltage drops to 10.5 and will not charge above that. Your battery charges to proper voltage but your truck is drawing it down as we said in the other thread.

 

When was the last time your truck was run when you read this voltage?

 

How long has the truck been sitting off when you took this reading?