Car battery - tested good - but will not hold a charge.

Discussion in 'The Okie Corral' started by Z71bill, Aug 6, 2014.

  1. I have experienced this several times now -

    Auto battery tests out as GOOD (dealership & AutoZone both tested it) - but it will not hold a charge.

    Is there any way to really test a car battery so you can be sure it is still good?

    Even when it was so dead it would not even turn the engine over it was still showing 12.2 volts per my multimeter.:dunno:

    I assumed that the test equipment used puts a load on the battery as part of the test.

    I am considering buying one of these

    [ame=""] Schumacher BT-100 100 amp Battery Load Tester: Automotive@@AMEPARAM@@[/ame]

    But if the tester a dealer & AutoZone use doesn't pick up when a battery is bad - will this do any good?

    Wanna kill these ads? We can help!
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  3. SC Tiger

    SC Tiger EL GATO!

    Dead cell maybe?

    I had one do that - I charged it all day, then went to start it and nothing happened.

    Took it to Auto Zone (where I had gotten it from) plopped it on the counter and told them I need a new one. Got 50% of the cost of the old one from warranty.

    How did they test the engine? The best test I ever saw on one involved several steps, including revving the engine to 2000 RPM and a few other things. That is what found the dead cell. The battery was still starting the truck but was getting sluggish.

    #2 SC Tiger, Aug 6, 2014
    Last edited: Aug 6, 2014
  4. If battery is good. You may have a amp draw on vehicle that is draining the battery. Did you remove it and take it in to be load tested? Good luck. Hope this helps.

    Sent from my two-story outhouse.
  5. This is the original battery - and just hit the 4 years old mark.

    I figured it was about time to replace it anyway -

    Possible there is some other issue - but doesn't seem likely - go from fully charged to dead in a few hours - it would be like having the headlights left on. (I checked they were off!)
  6. SC Tiger

    SC Tiger EL GATO!

    Sounds like what happened to my wife's car. Gonna stick with my dead cell interwebz diagnosis.
  7. Check your battery cables and connections. You should have bright shiney metal everywhere.

    I've seen battery cables that look pristine on the outside be full of nothing but green goo. Slice open the insulation on your cables near the end and inspect the conductor itself - again it should be bright shiney copper. Obviously you'll want to seal the cut well after this, or you might cause exactly that problem in the future. You can also try and start the truck and then feel the cables for warm spots.

    You can also try swapping in a known-good battery to see if your starting problem magically goes away.

    I've had starters, alternators, and batteries all test good, yet fail in service. A replacement cured their ills.

    Edit: At 4 years, your battery is probably toast. Seems like there's not much warning anymore - a vehicle starts fine one day, next day the battery is a doornail. I've taken to replacing them at three years, regardless of how they behave.
    #6 Diesel_Bomber, Aug 6, 2014
    Last edited: Aug 6, 2014
  8. I had two choices on battery size - H5 or H6

    The original had 540 CCA - my choices were a 650 CCA battery for $105 or a 730 CCA for $112.

    I went with the 730 CCA - it seemed like a little more power for not much added cash.

    I also could have installed a battery that is listed as a H6 AGM Absorbent Glass Mat it was $160 and I did not know what AGM was - so I passed on it.
    #7 Z71bill, Aug 6, 2014
    Last edited: Aug 6, 2014

    ERASER Nyuk,Nyuk,Nyuk!

    I had much the same problem. The car was fine if it was driven every day or so but the battery wouldn't crank the engine after a few days.
    I took the + lead off of the battery and put a multimeter with a built-in ammeter on it between the battery and the now-removed cable. It showed that there was a high amp draw even though nothing but the "normal" equipment was on (i.e.: the constant power to the clock and the radio).
    I kept pulling and replacing one fuse at a time until the amp draw dropped to well under 1 amp. It turned out that the factory radio amplifier kept pulling power even though the radio and the ignition switch were both OFF. This parasitic drain would kill the charge in the battery if the car wasn't started and driven every day or so to re-charge the draining battery.

    A quick question: With a fully charged battery, if you disconnect the - cable and let the car sit for a few hours, would the battery lose it's charge?
    #8 ERASER, Aug 6, 2014
    Last edited: Aug 6, 2014
  10. G30SF/F-250

    Platinum Member
    1. Glock Talk's Drunk Squad

    Are the terminals clean?

    Is the alternator charging the battery?
  11. I've had that happen twice. Tests good.....still runs down. Got a new battery both times and was off and running. I think their definition of "good" is bad.

    I also had a battery that wouldn't hold a charge because a wire from the alternator was bad.
  12. All good advise --

    I would have done more testing if the battery was not 4 years old.

    I was surprised to discover that same battery that goes in a 2.5L 5 cylinder VW Jetta (gas) is also the spec for my V8 Chevy Tahoe.

    I considered doing a swap - but the dam Tahoe battery is a PITA X4 to remove.
  13. AutoZone tested the alternator after they checked the battery - they said it was charging in the normal range.
  14. After I jumped started it today and drove it over to Sam's Club (about 10 miles) the car would not restart.

    So bad alternator is a possibility - but the idiot light does not light up - and the AutoZone alternator test was good.

    I told my daughter (her car) I was 98% sure it was just a bad battery - but it is possible something else is wrong.
  15. SC Tiger

    SC Tiger EL GATO!

    Really? Where is it located? On most trucks it isn't that hard, but Chevy has been known to bury stuff.
  16. Terminals are bright and shiny -
  17. Mine is a 2007 - they left the battery tray in the original location - drivers side corner all the way to the front - easy to get to - but they installed the battery on the passenger side all the way in the back of the engine compartment.

    It is wedged in between between some hoses - maybe one from the AC and the coolant reservoir tank. You need to remove a bracket & it looks like you will have just enough space to pull the old battery out without removing the hood.

    I don't understand why they left the second battery tray in place - I always figured maybe they were thinking about a diesel option so they would have two batteries.
  18. di11igaf

    di11igaf ibew

    You should read around 14.2 volts or so while the truck is running with a good alternator. See what it reads, bet its in the 12 volt range, which would indicate a bad alternator.
  19. Thanks - good idea - I will use this in the future - can't believe I didn't already know this simple test.

    I just tested it with my free Harbor Freight multimeter.

    12.7 volts with engine off

    14.3 volts with engine running

    I feel more sure than ever it was just a bad battery -

    If driving 10 miles 45 -50 MPH - doesn't put enough of a charge in a battery for it to even turn over the engine once -

    It seems like battery is the problem.
  20. VC-Racing

    VC-Racing General Flunky

    Fully charged 12v battery should read 12.73 v. I thing there is a parasitic draw . Turn everything off. Close all the doors , then remove the pos cable and get a test meter . Connect the meter between the pos cable and battery post. Watch the meter and begin to pull the fuses until it shows a reduced voltage. When you get that reading, reference the owner manual for the circuit.

    Sent via da Samsung S4 and da Ohubs Camp fir app
  21. I think I will let it sit over night and test it in the morning - before I do any more work-

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