Saturday, August 20, 2016

Why is My 12 Volt Battery Reading as 13 Volts?

Inside diagram of Lead acid battery
All 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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