Battery/alternator problem

[gparrow]

Wife's truck is having issues, it won't start without a jump.
alt is putting out 14v and both batteries read 12.6v separated off and 13.5v running I'm checing for a draw right now but do the readings on the batteries soud ok, my f350 7.3 reads the same about 12.6v on both batteries.

[08pwrstrokr6.4]

if it doesnt die going down the road its not your alt,or its just barely starting to go anyway.sounds like something else.i would say batts but if your other truck is reading the same i dont know.how old are they?and how cold is it?

[gparrow]

the batteries are 3 years old, I drove it for a little while and they charged back up to 12.6v. We are in South Louisiana it hasn't been verry cold. It seems to be an intermitent problem, i've noticed over the last month or so that occasionally it will turn over slowly but has always started. I cleaned the posts and cables that seemed to help some and then she went to leave work last night and it was dead.

[nitrogen]

can you do a load test and test the cells with a hydrometer. poor mans load test= good volt meter, leave the lights on for 1 minutes then have someone start it while you test voltage at the battery. 10.5-11.5 while cranking and the batteries are ok

[08pwrstrokr6.4]

^^^^^check that.but if it keeps it up from there id say its the batts.depending on what kind they are they may be old and cruddy.to have a sure check on it take it to auto zone and have them test the alt. while its on the truck.

[BigEZ]

If your alternator is puting out more than 14V it isn't the problem. I had the same issue this weekend, batteries dropping to 12.4V. Turns out one of my batteries (drivers side) was pulling down the other until they were in equalibrium. You may have a shorted cell in one of your batteries which is dropping your available cranking amps.

I took my truck to Wal Mart, had them seperate the batteries and analyze them. One battery was down to 150CCA, the other 650CCA. If you're going to replace one, replace both. For $168 I replaced both with 850CCA batteries and my truck now works like a champ. They are the same batteries as the AutoZone Duralast, but at less than half the price.

[nitrogen]

another thing is to totally clean all the battery connections and top up the water. the posts will develop a hard scale that really resist electric current.

[QMartinez]

I just replaced my alternator for similar issues. My edge showed it putting out 13.5 -14.2 but my batteries would crank slowly in the morning and would test 12.1-12.4. While driving it to have the alternator checked I noticed that the volts dropped to 11.8 but would shortly move back to 14.0. Apparently my alternator was working intermittently. Replaced my alternator and no issues.

Batteries tested good.

[bkvanbek]

My truck, has also not started a few times. Taken batteries out had them tested, both 5xx cranking amps and 12volts about. Alternator, with truck running The truck sat for 4 days and started.

But today, it barely started, I drove for 15 minutes, shut it off and immediately it would not start. 11-12 volts, jumped it, and the alternator 13.5volts. When at idle the radio would shut-off, presumably from not having enough power.

[08pwrstrokr6.4]

sounds like the alternator for sure.