There is a very big difference when a car battery drops even a small amount of voltage. When a car drops, for instance, from 12.6 to 12.0, there will be 75% difference. Its power drops from 100% to 25%. At 12.4 volts, a car battery is 75% charged while at 12.2 volts its 50% charged. https://carbatteryworld.com/car-battery-voltage/
Car battery voltage – Car Battery World
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