WARNING
When the vehicle battery is charged, it produces highly explosive
hydrogen gas.
Charge vehicle batteries only in well-ventilated areas.
Never charge a frozen or thawed battery. A dead battery can
freeze at temperatures around +32 °F (0 °C).
You must replace the vehicle battery if it was frozen.
Incorrectly connected cables can cause a short-circuit. First
connect the positive cable (+) and then the negative cable (-).