Phantom units have a constant voltage charger with
thermal regulation and current limiting circuitry to maximise battery life. The
chargers are fitted with thermal, current and short circuit protection devices
and a low voltage disconnect circuit to prevent the batteries entering a deep
discharge state in the event of prolonged power failure. Batteries are
maintenance free, sealed lead acid with a life expectancy of five years under
normal conditions.
The LED indicates that the
charger is functioning and that the battery is connected. It also indicates that
the filaments of the lamps are intact. If the LED is not lit when mains are
healthy, check the battery and lamps.