Quote:
Originally Posted by win911
Yes....that is why when you check a 12v auto battery it reads 14 ish volts and not 12.. because 1v is actually 1.2v.
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Wrong. This logic applies to NiCad batteries and consumer dry cells not lead acid. A fully charged healthy battery-out of a car- should read 11.9 to 12.5 volts. Most car batteries have six cells, each aproximatley 2 volts. Installed in a properly operating car, the voltage should be 13.5 to 14.5 volts. The higher voltage is generated by the alternator and this higher reading is an indication that the battery is charging and that the charging system is operating properly. Accessories that draw large amounts of current will pull the voltage down. Any reading less than 12V indicates that the alternator is not charging the battery and the system is 'drawing' power from the battery.
To the OP's question/ problem:
1. Have someone check for high resistance grounds. Connecting an ohm meter from the neg battery terminal to the alternator body will reveal if the ground connection has high resistance. A good reading should be very close to zero.
2. Pull fuses on accessories one at a time to see if one or several are at fault for excessive draw.
3. Check all electrical connections at battery and alternator and ensure they are tight. Any missing ground straps?