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How long do the different batteries last with a single LED (32 and 9V for example)? Answered


A long time?

  • Look up the number of mAh (milliamp-hours) that your battery holds.
  • Then look up the number of mA that your LED is supposed to draw
  • and the voltage at which it is supposed to operate.
  • You also need to know whether the circuit has a regulator (like the Joule Thief project).