Abstract: The present disclosure provides an emergency lighting system that includes battery charging circuitry to charge a rechargeable battery based on available AC power; and emergency power level control circuitry configured to detect a power outage of the AC power and determine an available output capacity (ACP) of the battery based on a normalized output capacity of the battery; the emergency power level control circuitry is further configured to determine a lighting protocol to deliver a foldback power level of the emergency power level control circuitry, the lighting protocol being based on determining if ACP is less than a selected value; wherein the foldback power having a first power level Preduced, where Preduced is less than FRP, delivered for a first time period, a second ramped down power level delivered for a ramp down time period tramp, and a third minimum power level Pmin delivered for a third time period.

Abstract: The present disclosure provides an emergency lighting system that includes battery charging circuitry to charge a rechargeable battery based on available AC power; and emergency power level control circuitry configured to detect a power outage of the AC power and determine an available output capacity (ACP) of the battery based on a normalized output capacity of the battery; the emergency power level control circuitry is further configured to determine a lighting protocol to deliver a foldback power level of the emergency power level control circuitry, the lighting protocol being based on determining if ACP is less than a selected value; wherein the foldback power having a first power level Preduced, where Preduced is less than FRP, delivered for a first time period, a second ramped down power level delivered for a ramp down time period tramp, and a third minimum power level Pmin delivered for a third time period.