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Low Voltage


Low Voltage refers to the condition when the alternator is not charging correctly in a vehicle. A battery sign will illuminate your dashboard that indicates a charging failure. A red battery sign will show in your dashboard that indicates a charging failure. According to the IEC (International Electric Commission),low voltage is defined as 0 to 1000 V  a.c or 0 to 1500 V d.c 

  • An undercharged battery, wherein a slow cranking is occurring, makes the lights dim excessively during cranking. for an overcharged battery, it means that electrolyte level might be low, and may spew from battery vents. This causes the lights to flare excessively when the engine speed increases, which shortens battery and bulb life and may also damage electrical parts.

A charge indicator in the instrument panel alerts the driver about the operating condition in the charging system. The three types of charge indicators are ; The ammeter, which shows current flow to or from the battery; The voltmeter, shows the voltage across the battery or charging voltage, and lastly. The charge indicator light shows the b battery is not charging. 

  • The ammeter connects the circuit between the alternator BAT ( a heavy black wire with a colored stripe) terminal and the battery. Current, except cranking current flows to or from the battery flows through the ammeter, which enables the pointer to short amount and direction of current flow
  • The voltmeter is capable of measuring voltage across the batter, When the engine is ideal, this is considered to be the battery voltage. With the engine running, the voltmeter reads charging system voltage.
  • The charge indicator light comes on when the key is turned on and serves as a bulb test and indicates the alternator is not charging the battery