////////////////////////////////////////////////////////////////////////////////
// 32sixteen.js
// Global scripts for use on 32sixteen.com
// Author: Nick Wallis
//
// Modification History
// 2006-10-30
//	!	Created
////////////////////////////////////////////////////////////////////////////////

//==============================================================================
// Calculates the life of a battery given the necessary battery and bulb 
// information
function calculate_battery_life (
	battery_voltage, 
	battery_life, 
	bulb_wattage, 
	bulb_voltage) {

	// sanity checks...
	if ( battery_voltage == 0) {
		// catch divide by zero...
		alert ("Battery Voltage must be greater than zero");
		return 0;
	}

	over_voltage = (battery_voltage / bulb_voltage ) - 1;
	over_voltage_percent = 100 * over_voltage;
	power_overload = 1 + (over_voltage * 1.5);
	power_drain = bulb_wattage * power_overload;
	current_draw = power_drain / battery_voltage;
	battery_duration = battery_life / current_draw;

	document.calculator.over_voltage.value = over_voltage_percent;
	document.calculator.power_drain.value = power_drain;
	document.calculator.current_draw.value = current_draw;
	document.calculator.battery_duration.value = battery_duration;

}