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Why do some flashlights drain batteries when off, how to avoid?

Discussion in 'XTAR (flashlights, battery chargers, batteries)' started by XTAR, Sep 30, 2021.

  1. XTAR
    • Sponsor - Manufacturer

    XTAR Loaded Pockets

    Apr 21, 2016
    Likes Received:
    You may wonder why some flashlights drain batteries even when they are switched off and not in use. The batteries left inside the flashlights slowly lose charge, because of what is known as parasitic drain. And It’s important to know if the flashlights can store for months/years with batteries, or the batteries may be empty when the light is needed.

    Most LED flashlights need a constant power supply in order to detect when it is being turned on. This constant power is what leads to parasitic drain. A general rule for detecting flashlights with standby power drain is to look after the switch, if it’s a non-locking switch, the light has a microprocessor that is always powered to control the power and for some lights they also need a running boost converter to power the microprocessor, which will increase the drain.

    To prevent parasitic drain, one of the best ways is to remove the batteries from the flashlights when storing the flashlights for an extended period of time. Regardless of the power consumption, it’s always best to remove your batteries from the flashlights, which will completely stop this drain on the battery power, no matter of they are electronic switches or mechanical switches.
    Nick4305 likes this.
  2. earthman

    earthman EDC Junkie!!!

    Jan 12, 2014
    Likes Received:
    Yes, very good point I'm sure, I have heard that flashlights that use a magnetic control ring to change light outputs are one of the worse for this? I do have a Sunwayman M11R funny enough, haven't used it for probably a year and half until recently, still working fine on the battery I forgot to remove before I stored it away.