Ron:

I once had a Sears diehard that one of the cells reversed it's polarity.  The guy at sears checing it didn't catch it, but I did.  He got a negavive reading on that one cell, so he reversed his probes and proclaimed it OK.  I called him to task on that, and they replaced the battery.  Anyway, if all the cells got reversed, it would knock out the diodes in the alternator.  Is it possible that the battery got charged backwards at the show?  Or jumper cables hooked up backwards?  Either one would trash the diodes.

John - "The Hoosier Hurricane"

Hi Guys,

A little clarification:

I didnt hear any weird noises with the "new" battery.  however, I also didnt run it too long with it in there, since it wasnt mounted well, etc.

Volt meter at the battery terminals read 12.4v while running; 12.5 while not running. 

Reading on the volt gage under dash has been/is consistent with voltmeter at terminals

Belt has been tightened/retightened

Revving engine to >2k (in an attempt to get alternator to kick on) yielded no change

Gage array under dash is fused; would have thought that would have blown if there was a short?

Previous to all of these problems, the gage under dash would regularly start at ~12v, then when the engine is revved to above about 1200, the needle would kick up to the normal 14.5, and would stay there until car is shut off.  Because of that, im skeptical that it doesnt kick on because the battery is fully charged?

All wiring in the car was new 8 years/about 17k miles ago

Is it possible that the bad battery killed the new alternator on the 25 minute drive home?

Ron Grove

Wauconda, IL

I had a noisy alternator once years ago.Turns out a bad diode will cause a high pitched squealing noise.Is it possible the wire feeding your voltmeter is grounding or has a short in the wire?

  

Ron: You say the same result (voltage) with your daily driver battery. But are you getting the noise etc? If that battery is fully charged, your replacement alternator may not be kicking in. Off the top of my head the squeeling sounds like a slipping belt. No?

Paul

So I also just tried hooking a jumper cable from neg terminal to alternator body just in case it was a ground issue....no change.

Ron Grove

Wauconda, IL

Maybe Steve Metzger will see this post.Pretty sharp guy on electrical stuff.Maybe you should put this problem in the technical posts?

  

Ok, so I just tried the battery out of my daily driver.  Its about   a year old.  Same result.  Shows about 12.4v running, 12.5 when shut off.  Im really stumped since this thing is wired so simply....any ideas?

Ron Grove

Wauconda, IL

Ron:

The battery tested bad.  Replace it.  If there is still a problem, it is there whether the battery is old or new.

John - "The Hoosier Hurricane"

Yes, I may do that tomorrow. Its a pita to get the battery out of my dd to test, but I miight try that. Either way the battery tested bad under load so I probably need one, but id hate to do it and find yet another problem!

Thanks!

Ron Grove

Wauconda, IL

Ron-Why not swap a known good battery just to test your theory.Doesn't have to fit the battery tray-you are only trying it at idle and see if the alt. charges.I dont know why a bad battery  would affect the alternator but try a good battery and see.