Abstract: An electronic circuit and/or method that determines a type and/or size of a battery in a light and controls operation of a light source may comprise: a circuit measuring the voltage of the battery; and a processor for determining the measured battery voltage. The processor may compare the measured battery voltage and a predetermined voltage and set an operating condition of the light source based upon the difference between the measured battery voltage and the predetermined voltage. The processor may apply a predetermined load to the battery for a predetermined time and measure battery voltage during the predetermined time; and determine the difference between the measured voltage of the battery and the measured battery voltage during the predetermined time.

Abstract: A portable light may comprise: a generally rectangular light body having a pair of opposing extensions or projections thereon, the light body having a generally rectangular cavity for receiving a source of electrical power therein; a generally cylindrical light head rotatably supported between the extensions of the light body adjacent the light body, the light head including a light source for producing light; and a switch for selectively actuating the light source. The light may include interchangeably a generally rectangular battery or a plural cylindrical batteries, and the battery or batteries may be rechargeable.