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Crank flashlights: Which batteries are in there?

Discussion in 'Electronic Design' started by Joerg, Sep 17, 2007.

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  1. Joerg

    Joerg Guest

    The umpteenth flashlight was completely corroded out by a battery that
    leaked despite the fact that it was delivering power. It almost wrecked
    a nice cabinet along with it. So, I just got a flashlight with crank
    from Costco. Duracell KP028, two for $15, even has a radio with weather
    band in there. Now I am curious: Does anyone know what kind of batteries
    are in there? Maybe even a super-cap?

    Google didn't lead to any hints and according to the Duracell site they
    don't even make them (!). Then again their site isn't very good, lots of
    "The system cannot find the path specified."

    I am not a fan of LEDs, they just aren't as bright as regular flashlight
    bulbs. But this thing is pretty good. One minute of cranking and it
    lights long enough to find stuff, even keeps its charge. Ok, they say 30
    minutes but it gets dim after 5-10 minutes. Good enough for me, if the
    battery holds up over the long run.
     
  2. _

    _ Guest

    I took apart the small one I just got and it had a 40mAh NiCad. Rounded
    case, about 3" x 1.5" x 1", three LEDs, on-off slide switch, short attached
    wrist-strap like those on digicams. $6. Works quite well, brighter than
    the bigger one I got last year, nice and small, fits in one hand.
     
  3. Jim Yanik

    Jim Yanik Guest

    IMO,Duracell batteries are prone to leaking.
    If they are used in your crank flashlight,then that will fail,too.
    Get a flashlight that uses lithium cells.
    The 1W and 3W Luxeon LED lights are pretty good.
    IF.
     
  4. Guest

    When I took apart my crank LED flashlight to fix the switch I found to
    my surprise a large capacitor instead of a battery. Explains why the
    thing is so damn light. Not as bright as a regular flashlight but I
    find it usable. Mine uses a ratchet based crank for single handed
    operation so I can actually use it while cranking. Don't know the
    brand though.. probably made in China.. I got it as SWAG from a Fluke
    booth at a convention.
     
  5. Joerg

    Joerg Guest


    That's what I was thinking (but still hoping for a super-cap...). I
    guess that NiCd will eventually croak under these frequent and partial
    cycles. Just like those for my lil' hand grinder. Lasted only one year :-(
     
  6. Joerg

    Joerg Guest

    Hmm. They also had a four-pack of others but I figured a brand name
    might be better. Plus the radio feature is nice in case the really big
    shaker comes.
    Well, great, here you just blotted out my optimism ... Oh well, let's
    hope it lasts. We also have a humongous $10 flashlight with a lead-acid
    gel cell. It was said not to last but surprisingly it has now lasted
    three years. We use it every day to clean up after the dogs when they do
    their late night potty. You can light up the road signs clear across the
    valley with that one.
     
  7. Joerg

    Joerg Guest

    Then it should last nearly forever. Well, until something mechanical
    gives up. Mine won't open without destruction but what surprised me was
    that the lights they had there at Costco lit nearly for the max time,
    sans cranking. I tried the one I bought: Turned it one, went through the
    store to load all the other stuff I needed, returned 20 mins later and
    it was still going. At least a NiMH would not hold a charge for months
    while shipping.
     
  8. Jim Yanik

    Jim Yanik Guest

    I've been buying Fuji Novel alkalines,they don't leak and they are cheaper
    than Everready or Duracell,seem to last just as long.
    For what you paid,it was an OK buy,IMO.
    I had a couple of 12v 20AH gel cells(scooter batteries) that came in handy
    after Hurricane Charlie took out my electricity for 7 days;I used old PC
    power supply fans to give me a mild breeze to sleep in the hot,humid
    Florida weather,and had a 12v fluorescent lamp for light.

    But they eventually succumbed to sulphation. :-(
     
  9. Jim Yanik

    Jim Yanik Guest

    This reminds me of the $3 "forever" shaker flashlight I bought,only to find
    the coil was not connected,no storage cap,and two lithium coin cells
    actually powering the LED.(1 CR2032,1 CR2025)
     
  10. Joerg

    Joerg Guest

    It's hard to find brands other than Duracell out here since that is what
    Costco and other discounters carry. At the supermarkets batteries are
    really expensive. Had to do the scraping and vinegar thing on our
    emergency lantern yesterday. Same thing: Lit up brightly on both tubes
    but one D-cell had oozed all over :-(

    Yeah, I guess. It also has an amber blinker LED. I want to try that
    during our evening dog walks. Sometimes we chat with neighbors and
    whoops, it's dark. The usual lanyard blinker gizmos are mostly junk,
    fell apart on us. Costco also has a headlamp, maybe I'll see if I can
    mod that to red and wear it "in reverse". It's all a 25mph zone here but
    some of those kids really tear down the road.
    We have a Statpower "suitcase" with a piggybacked 300W inverter. It has
    kept the wood stove fans going for six hours once. Very nice. For longer
    periods one can connect a car battery to it.

    But they still last an amazingly long time.
     
  11. Gary Tait

    Gary Tait Guest

    Mos likely some sort of recharegable battery rather than a supercap for
    that one. My 3 LED crank light uses a NIMH pack, although my 1 LED
    shake light uses a Supercap.

    Most likely they leased out their brand for those devices.
     
  12. Eeyore

    Eeyore Guest

    Super caps don't have the energy density required.

    Graham
     
  13. Eeyore

    Eeyore Guest

    Maybe the Chinese manufacturere just 'borrowed' the Duracell name ?

    Googling "Duracell KP028" just leads to ebay which is a bit of a giveaway.

    Graham
     
  14. Joerg

    Joerg Guest

    Yes, and a lot of people brought them back to the stores because of
    premature "failure". Lack of honesty usually doesn't pay.
     
  15. Joerg

    Joerg Guest

    If they market these in Europe it couldn't be NiCd. I've never seen a
    shake light. Wonder if scraping out the super cap and LED would beat the
    Digikey prices for super caps (pretty high).
    That would be a rather dangerous business practice. If they hold up,
    fine. But if they don't, hoo boy. They have their corporate address in
    CT on the warranty slip. AFAIK they belong to PG now.
     
  16. Joerg

    Joerg Guest

    Well, these are carried by Costco and the package has the correct
    corporate address for warranty returns on there. Costco is a major
    country-wide discount chain here in the US, they could not possibly sell
    merchandise from "shady" sources. Or let's say they could only do that
    once ;-)
     
  17. Joel Kolstad

    Joel Kolstad Guest

    Probably because they're a gimmick -- "shacking" is just about the most power
    inefficient way I can manage to turn human motion into electrical energy!
     
  18. The factories get paid up front. It doesn't pay to be lazy in spot
    checking and evaluating product from third-world countries.


    Best regards,
    Spehro Pefhany
     
  19. Joerg

    Joerg Guest

    One has to hope that the merchants or whoever ultimately pays for the
    loss learn. A classic example was a lanyard lantern my wife wanted to
    buy from a hardware store, for walking the dogs after dark. The clerk
    finally gave up after the whole thing fell apart upon battery
    installation and exclaimed "That stuff really is junk, as you said."
     
  20. Joerg

    Joerg Guest

    That's what I thought. It's kind of ok for watches where little energy
    is needed. But even there you can buy "shaker cradles" to place them
    into at night if you don't exercise them enough. It's quite a joke IMHO.
     
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