An emergency lighting unit usable with different types of batteries

The emergency lighting unit comprises a connection for a battery (5), an inverter (9) for supplying, in emergency conditions, a discharge current from said battery (5) to a lamp (L) connectable to said unit, and a battery charger (7). Means are also provided for setting a minimum operating voltage (Vundervoltage) across the terminals of the battery, below which the discharge current from said battery is interrupted, said minimum operating voltage being variable according to the rated voltage of the battery (5).