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2004 charging voltages ,

Discussion in '2002 - 2005 Ford Thunderbird' started by succulentfire, Aug 7, 2017.

  1. Hello , just joined the forum with my 2004 , as i look further into my new purchase i find my self checking the charging system , i have driven the car close to 400 miles with no problems , however before my 400 miles as i put my meter on the battery the voltage i find gets me concerened . before start up i get 12 .2 volts , after start up the voltage bumps up to 12 .7 car idles at this and as i rev up and at idle sometimes moves up to 12.9 even seen it at 13.5 (not often so far) . most of the time driving its 12.7 , increase load with AC load and lights voltage drops to 12.4 but then quickly climbs up to 12.9 , i have always thought charging systems should be 13.5 min ..when ever alt is turning . no dash light and no dead battery .... so far ....is this some different type of battery tendering ? Thanks for looking
    tbird likes this.
  2. captrick

    captrick Well-Known Member Lifetime Donor

    Try turning everything off in the car. Start the engine and let it come up to temperature then start tuning options on one at a time. Check the voltage after you turn each options on. If you are not happy with the readings on your volt meter find another one to use. You see as the battery in your volt meter gets older the voltage in the battery drops. When you turn on the meter set it to continunity and set the needle on zero. You might have the correct voltage when charging it might read low because the battery in your meter is week. As you turn on your options and the voltage only drops a little everything might be ok it could be your test meter that needs to be calibrated. Good Luck Rick
    tbird likes this.
  3. Thanks for Your interest Rick ...the reading is correct ...2 different meters ...I believe the charging system has some issues ...but for now is keeping up with the demand of use ...i drive this car as a summer toy ...and will keep an eye on it to see if it gets worse ..I see quite often 13 volts at start up then down from there ...but never lower than 12volt while loaded and running ....
    tbird likes this.
  4. JW in Dixie

    JW in Dixie Well-Known Member Lifetime Donor

    It's the voltage regulator doing its job. As demand increases the regulator adjusts and vice versa, keeping the battery just right. Unless a low battery condition arises, I would not worry and stop checking. Enjoy the ride! :)

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