car-battery-and-the-deaf

A deaf driver was driving for a long time with a
weak battery. There was no warning signal on the dashboard
about a weak battery.
A hearing friend happened to hear the car engine and
said “your battery is weak; I will jump the battery for you”
How did the hearing friend know? He said he heard clink,
clink while the engine was turning and knew the battery was
weak.
Lucky to have a hearing friend!