On a 1999 Ford Taurus...?

  • Thread starter Thread starter Josh B
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Josh B

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The battery voltage on my grandmothers Taurus has run down. It was fine a while ago (a month) but now the car is not even starting. The battery was charged up with a battery charger because it ran down, the car was not driven in a month. So after that the car started and when the car was started the alternator output was putting out 13 volts. Each day for 3 days after that my grandmother started the car and let it idle for 10min to keep the battery charged because of the recent cold and she is not able to drive it because of her vision at the moment. On the fourth day the car didn't start. Is this because the Alternator is not putting out enough for the battery, because the car is not running long enough, or is the battery going bad.
 
if i recall right when you charge the battery if you pull off the positive battery cable while running and the car dies its the alternator,if not its the battery..also try to scrape the insides of the terminals what connects to the battery post with a pocket knife..scrape em up good i just had this problem..
 
I will start this off. The alternator should be putting out 14.5 volt to charge the battery. 13 volt is a fully charged battery. At idle the car need to run 30 minutes.
 
I am going to guess the battery is going bad if it will not hold a charge. You can take it to a good parts store and they will check it for you. 13 volts is sufficient to charge the battery.
 
Normal alternator voltage is between 13.5 -14.0 volts. If it's not within that range it's not charging properly. You could let run through a tank full of gas @13 volts and not charge the battery. On the other end of the scale voltages over 14 volts actually boils the acid/distilled water out of the battery and usually winds up warping the cell plates.
 
13 volts is on the low side although you don't mention at what RPM. You should have a minimum of 14.2 at anything above idle speed.
 
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