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Can a battery be bad but test good voltage?


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I was under my hood and noticed some stuff coming out of the + terminal that I suspected to be acid. So I tested the voltage and got 12.6 volts. Then I tested the amperage with the car running and got no amps from + to -. Yet when I disconnected the kinetik and tried starting the car it still started. Without amperage wouldn't the car not start?

Reason I ask is because I lost quite a bit of power in the past month or so and I'm wondering if that's why.

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Yes, it can read a good voltage but still be useless. You need to have a load tester to put a load on it and see what it does. If it's bad, the voltage will drop quickly down below 11V.

Ryan Miskin - owner of RAM Designs


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i doubt you have no amperage.. normally when a battery is dead it will sit below 12v... and what are you testing your current with, you cant test it with a multimeter

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How did you test the amperage? Normally testing amperage has nothing to do with both Pos and Neg terminals.

Are you sure you have a meter that can read DC Current?

Ive seen people before saying so and so alts are junk barbecue they dont charge, but yet they where using a A/C current clamp meter on a DC current electrical setup...

Not all clamp meters can measure DC Current, but most will do A/C and D/C voltage, but only A/C amperage.

If the battery has a bad cell it would be a significant drop in resting voltage. The normal size of a battery cell is 2.1 - 2.3 volts, so if the battery was bad, or going bad, your voltage would be around 10volts.

More than likely the residue you seen coming out of the battery is corrosion, it happens to good and bad batteries and as nothing to do with the life of the battery or does it say that the battery is taking a :poop:

 

 

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