Possible Charging Problem???

**Joe K. 99 Zeee!!** · 07-03-2006, 03:05 PM

On a drive yesterday, I notice the turn signal blinking slowly and A/C isn't putting out. The Check Guages comes on and sure enough, voltage is deep in the red. Then the ABS and Traction Control go out. Seems like it's shutting down unecessary systems to preserve battery power.

I had the shop down the street do a start and charging test. They pronounced the battery DOA. So I got a battery, threw it in, and according to them it passes the test.

I'm still not sure. On the drive back I watched the voltmeter closely. With A/C and stereo on, it's reading just above the line between 8 & 13 volts. That's right around 11 volts. With engine off and key in run position it reads maybe 12 volts. For a moment while driving stayed at 14 volts, but only for maybe 10 seconds.

Owner's manual says to worry only if it goes below 11 and stays there. It's borderline and making me uneasy.

Picture for reference.

**2001NBMZ28** · 07-03-2006, 03:25 PM

That seems too low, been through a couple batteries now and new ones have always charged higher at first, way past 13V until they settled in - probably because they've been on the shelf for a while. Put a digital voltmeter across the battery terminals cold/hot and see what it reads.

**Joe K. 99 Zeee!!** · 07-03-2006, 03:27 PM

I'll have to borrow a voltmeter tomorrow. It tested over 630 amps when I picked it up at the store today.

**2001NBMZ28** · 07-03-2006, 03:43 PM

You're not looking for amps with a new battery, see what the voltage is on start up (what the alternator is doing) - thinking it should be 14-14.5 on a cold start, then should settle down just over 13 when warmed up.

**Joe K. 99 Zeee!!** · 07-03-2006, 04:01 PM

I'll do that, thanks for the replies!

**Joe K. 99 Zeee!!** · 07-04-2006, 04:58 AM

I took some readings this morning myself. Battery shows 12VDC with the key in the run position, engine off. Engine on, it shows between 11.5 to 12.5. It jumped to 14.5 once for a moment. At times it was very briefly showing 6-9 volts with the A/C and lights on.

Service manual says 13-16 volts after running for 5-7 minutes. It's certainly not up to spec. I'll have to wait till later to fix it. I'm going to enjoy some time with the family today!

Most likely the alternator is bad due to my last battery going dead. From now on, I'm not waiting to change them out. After 4 years, I might as well just get a new one. After that long, the prorated warranty is not going to do much good anyway.

**02z28ls1** · 07-04-2006, 05:46 AM

You were referring to the CCA rating of the battery (Cold Cranking Amperage) but it appears you haven't had the charging system tested for amperage output. If your voltage is jumping up and down that much -it's a good bet the alternator is bad. It may be that the voltage regulator part of the alternator is to blame but that's not important. You needed to have the charging system tested with a good battery, you won't get good test results otherwise. Autozone will do a free charging system check for you, it would clear up all this mystery for you. Check for a loose connection at the alternator and/or battery terminals-they need to be clean and tight. A slipping serpentine belt will also give these symptoms,check the tensioner.

**IronBird** · 07-09-2006, 06:04 AM

Dude, I was having similar electrical "gremlins" also that was making me pull my hair out with 2 batterys, and everything checking out "okay" (batt & alt) when tested. Long story short: my POSITIVE battery cable insulator (that red rubber cover on the end that connects to the battery) had corrosion CAKED under it, that wasn't visible unless you "skin back" the cover, otherwise it looked "clean" from the outside...I couldn't believe it!! I cleaned it up real good after completely removing the cover first...silicone greased it and put it back, and no problems since. Hope this helps.