You keep driving with bad batterys you will burn up your alternator!

 

I believe your alt. is fine it sounds like the batteries are bad. If after being on a charger for 24 hrs and it only shows 12.8 v then the battery is bad. coming off the charger you should show a surface charge of over 13v

 

Thats what I have been worrying about more than anything, ruining the alternator. Even though the batteries have been load tested and they say they're fine, something's just not right. Im going on the second 24 hr period of charging them, first 24 was with 10 amp automatic charger, the second was with a 2 amp float charge.

In the morning Im going in and if they tell me they're fine I'm gonna pull them and take them back there and let them charge them overnight and then let them see what they're doing. The only good thing Ive got going on that front is that Ive spoken to Optima and an engineer there is working with me. If AutoZone says they're fine, Ill get the engineer involved. he's the one who said they may be sulfated.

Anyway, thanks for all the support. And Scott, Ill switch trucks with you ANY DAY... mine needs a good a*^ whoppin, and I know you'll put her tail to work. Thanks for all your help guys.

 

Why did you replace good batteries? Motorcraft batteries are pretty good for what they are, I just replaced the 10-year-old original battery in my Contour a couple months ago.

I have yet to see anything credible that states that Optimas last longer than other batteries.

 

I am starting to think, like others, that its a battery problem, not the alternator.

Sam

 

The batteries were replaced because the primary went bad. Several of us had this problem. It started with a "Check Brake System" light at startup, and when several people went in to have their brakes checked, someone finally figured out it was the batteries. Sure enough several of the 08's had primary batteries go out. Whether it had anything to do with the primary not having an insulating blanket on it or not we'll never know. There's a thread here when all this happened from a year ago. As far as the Optima's, whether or not there is anything "credible" out there stating that, Ive read and heard alot about the Optima's. And as far as whats out there, I sure wasn't going to put another Motorcraft in it after what happened. You were around back then when we had all the "Check Brake System" messages weren't you Tom?

I am too Sam. No one wants to replace a battery if it passes a load test but the engineer at Optima said they would if it didn't pass certain parameters that a load test will usually "pass" a battery on. That's also another reason I bought the Optima's. Terrific support.

 

do it im running 15.4v with my 270 amp alt and missing link audio module so you're fine

 

Do you have the dual alternator option on yours? On the duals, the upper is a 120 amp alt, and the lower is a 200 amp alt.

 

nope single, but i dont see why you couldnt just run two 200amp, in reality the more of an over kill with the electrical the better.

also to see if your alternator is dead, do this, when your truck is on take the (+) off of the battery if teh truck shuts off that means it was running everything off of your battery, if it doesn't shut off then it isnt the alternator.

 

With all the electronics on these trucks I would not give that serge to your truck. I have know things to burn up if with low voltage!

 

don't take off either cable while its running you risk damaging the pmc with any voltage spike or loss that used to be true with the older cars and trucks but that was before computers started controlling everthing in the vehicle.

 

Yep. I agree. Back in the old days that was a way to tell, but these days with all the electronics and computers, and especially a dual battery system, its just not worth it. I'm pretty sure now, after all the reading and testing i've done, that my alternator is running like it should cause Its putting out between 14.0 and 14.8. Just a matter of getting the batteries figured out now. Thanks to everyone for all the help. Much appreciated.

 

Yeah, I was here. It always baffled me how a bad battery could cause such an elaborate electrical system to think there was a problem with the brake system. I was a skeptic when I first read about it, yet seemed like more and more people fixed their brake system warning with new batteries. Some things just don't make sense I guess!

I asked about the batteries because it appeared that you preemptively replaced your batteries to avoid a problem instead of replacing bad batteries after a failure. Looks like I assumed too much, and I apologize for that.

My comments about Optima batteries come from researching lots of different threads on this subject over the last 6 or 7 years here on FTE. On numerous occasions people posted about how great their Optimas were, and most of the time I saw just as many people talk about how they didn't really last any longer than most other battery types. I did some searching and had a tough time finding people that could say from experience that they truly were longer lasting batteries.

So when shopping for batteries I consider the fact that Optimas around here sell for about double what regular lead-acid batteries do. But they won't last twice as long. I guess I just don't like 'em!

But to each their own, with any luck you'll get this sorted out. I, too, believe this to be a battery issue rather than an alternator issue. I also believe that you will shorten the life of your alternator with bad batteries, so get it fixed quick!

 

Im working on it. And with help from these forums and the great people Ive met here Ive come closer to solving the issue. As far as the Optimas, I don't think that they are necessarily better than any other battery as far as longevity. I think most of the reasons people like them is because of their unique ability to withstand heat and cold so much better than a regular battery, due to their glass mat construction. And back when many of us were getting our brakes checked out ( ) we came to the conclusion that heat may have been a factor; especially since the primary's didn't come with an insulating blanket. But I wouldn't say that an Optima would last longer than any other battery. And no need to apologize my friend. It's difficult to hear inflection in these forums! You still lovin' that 11?

 

Yeah, it's been great so far. Had one warranty repair so far, they replaced the turbo because it was making a noise I didn't like on cold starts.

Otherwise it's great! Lately I've seen 18-19 MPGs for my regular highway commute, and it does an amazing job towing.