Battery Myth | Why is My 12 Volt Battery Reading as 13 Volts?

12 Volt Battery Really 13.2 VoltsAll Lead acid batteries (Gel, AGM, Flooded, Drycell, etc) are made up of a series of 2.2 volt cells that are bridged together in series to reach their final desired voltage. For instance, a 6 volt battery will have 3 cells(3 x2.2= 6.6 volts), a 12 volt battery will have 6 cells(6 x2.2=13.2 volts) and so on.That 2.2 volts is the fully charged, straight off the charger number. The actual resting voltage, or the voltage a battery will settle at 12-24 hours after being removed from the charger, is closer to 2.1 volts per cell, or about 6.4 volts for a 6v battery, and 12.7 volts for a 12v battery. These numbers assume 100% healthy cells, and may vary a bit lower for older batteries.

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  • The battery posts could be corroded the fluid could be low in one or more cell or the battery could just be bad. The danger in simply jump-starting a dead battery or placing it on a battery charger is that the battery may not be able to maintain a charge. The only way to rest assured that your battery will not fail you is to troubleshoot the battery and find the reason for the failure.
    Monex Scam
    December 15, 2010 a 10:52 pm
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