It's always the simplest things....

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jimmyjamm

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Trying to figure out how the tech showed 12.7 volts, but Auto Zone said it wss completely dead?
 

FordTechOne

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Trying to figure out how the tech showed 12.7 volts, but Auto Zone said it wss completely dead?

You can have static voltage without amperage. The tester is able to analyze the battery and determine the cranking amps. So even though the battery may have 12.6V (fully charged), it may only have 50 cranking amps out of the 700 it’s rated for, which means the battery is bad. Voltage alone cannot determine the health of a battery.
 

txgunsntrucks

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You can have static voltage without amperage. The tester is able to analyze the battery and determine the cranking amps. So even though the battery may have 12.6V (fully charged), it may only have 50 cranking amps out of the 700 it’s rated for, which means the battery is bad. Voltage alone cannot determine the health of a battery.


Pretty sure the process for that is using a multimeter have someone start the car. if it dips below 10 bad battery. As well as resting should be about 12.6.
 
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