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Home Made Li LED Flashlight?

Discussion in 'Electronic Repair' started by KenO, Dec 4, 2012.

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  1. KenO

    KenO Guest

    Have a couple of older Motorola cell phones with good 3.7V 950mAh Lithium Ion Batteries and chargers.

    Would like to use these Li batteries to make a Li LED Flashlight.

    Hope others have tried this and have some suggestions.


  2. mike

    mike Guest

    Suggestion: forget it.
    If you want a flashlight, watch for a sale.
    Or read the candlepower forums.
    Or try dealextreme.
    There are lots of very good lights cheaper than you can buy
    the parts in onezies.

    Do this thought experiment.
    Take out the battery.
    Unplug the charger.
    You just disconnected all the stuff in between that keeps
    the battery from catching fire when you charge it.

    And someone will surely chime in here and say that the battery
    has a protection circuit built into it.
    And they're probably right...probably.
    It's there as a secondary protection method in case the phone
    charge circuit fails. You do not want to rely on it for daily
    charge management.

    Depending on how old, the battery may already be shot.

    While it's possible to do what you want, it's not economically
    feasible and the result may not fit in your pocket.
    And it's very embarassing when your junk catches fire.

    If you knew what you were doing, you wouldn't be here asking.

    Find a hobby that's not so incendiary.
  3. mike

    mike Guest

    No need to get snippy with me.
    He asked for advice, I gave him some very good advice.
    And I told him exactly why it was a bad idea.
    And gave some suggestions on where to find a flashlight.

    I'd have given him the same advice if he'd wanted to power
    his car from a mixture of hydrogen and oxygen in the exact
    ratio to produce the most violent explosion.
    Just 'cause there are thousands of websites hawking the idea
    doesn't make it a rational endeavor for a newbie.

    Funny story. I've actually met only one HHO car guy in person.
    He blew the valve covers off his engine and destroyed
    the whole intake system when it exploded. But I digress...

    If YOU have some advice for the OP, this would be the thread
    to present it. Addressing me won't help him at all.
    Well, you can learn a lot from the wording of a question...if you bother
    to think about it.
    I expect that you're yanking on the wrong end
    of the chain. Sounds like the problem is that he has some phones he'd
    like to turn into something useful. Flashlight just might be
    the first thing he thought of.

    I don't question his reason. His hobbies are his choice.
    I question the sensibility of the proposed project and answered
    his question in a way that seeks to insure that he keeps ten fingers
    and two eyes and a house that's not made of charcoal.

    Your risk tolerance may vary. Advising a newbie based on YOUR risk
    tolerance is irresponsible.
  4. But if you were paying attention, that's his reply to the flashlight post.
    Then somehow his reply (maybe a paste where he didn't intend it) to the
    tablet charger post was tucked in below it. If you don't read his reply
    carefully, you do think the whole thing is about the flashlight, when it's

  5. hr(bob)

    hr(bob) Guest

    100% agreed
  6. You might want to drop by Home Despot and look for their 50-LED flashlight.
    It has a metal case, takes four AA (not AAA cells) -- and costs $10. Buy
    some 2500 or 2700mAh NiMH cells and a charger.
  7. mike

    mike Guest

    This is your second post in the thread.
    And you've yet to make any input to the OP.

    Let's hear your advice on how YOU would create a flashlight
    out of a cellphone.
    Don't skimp on the practical details.
  8. amdx

    amdx Guest

  9. whit3rd

    whit3rd Guest

    It's fairly easy to modify a variety of flashlights to take a different
    battery or lamp; the incandescent bulb/reflector assembly is big
    enough that removing it makes room for lots of electronics and/or
    odd batteries.

    The usual cellphone battery is rectangular, though, and relies on
    springy contacts to its pads. You'll need to make a rectangular
    holder, with (perhaps) pogo-pin contacts.
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