1. eNewsletter Sign Up

Charging question - I think I'm screwed...

Discussion in 'The Garage' started by ra2bach, Jul 25, 2007.

  1. ra2bach

    ra2bach drive-by poster

    Joined:
    Dec 11, 2003
    Oddometer:
    4,819
    Location:
    Alpharetta, GA, USA
    OK, this is not about a bike but I think it still is relevant to motorcycles. lately, I've been noticing my jeep has been slow to crank.

    I plugged my Garmin GPS into an accessory socket and the voltage shows between 12.7v and 13.0v at cruising rpm, and down to almost 12.5v at idle this is with air conditioner and radio on. if I turn these off, it will climb to almost 13.2v when accelerating.

    I assume this is not enough, correct? what is happening - bad voltage regulator, alternator, hamster not running around in the cage fast enough? :ear
    #1
  2. Dolly Sod

    Dolly Sod I want to do right, but not right now

    Joined:
    Aug 18, 2003
    Oddometer:
    18,873
    Location:
    Richmond, Va
    Could have loose or corroded battery connections, a bad battery cable, or battery on the way out.
    #2
  3. ra2bach

    ra2bach drive-by poster

    Joined:
    Dec 11, 2003
    Oddometer:
    4,819
    Location:
    Alpharetta, GA, USA
    you're right, it could. I didn't even think to check as it's a fairly new battery and I just had some major engine work (long block) so I know everything was R&R'd. I guess it's just my pessimistic nature that made me think it must be something expensive....

    thanks for your reply,

    ra2bach
    #3
  4. GreaseMonkey

    GreaseMonkey Preshrunk & Cottony

    Joined:
    Jun 16, 2006
    Oddometer:
    5,922
    Location:
    The only county in Illinois with no train tracks
    Check the simplest things first- you don't mention what year but if it has anything other than a serpentine belt check the belt tension.

    Next, check the voltage at teh alternator, with the negative probe on the alternator case and the positive probe on the output terminal. If it is less that 13.5 at high idle, touch the alternator output wire. If it is super hot then check your battery as has been suggested but if it is not that hot to the touch it points to diminished alternator output, and you should remove the alternator and take it to a place to be properly tested, which should be done for free since you'll be buying a new alternator if it fails.
    #4