How long should NiMH batteries be expected to keep their charge?

Discussion in 'Digital Photography' started by Anthony Buckland, May 30, 2004.

  1. In storage, as spares, that is. Having spare batteries with no charge,
    which has
    happened to me twice now, can be annoying when the first set of batteries
    finally run down. Bad batteries, or bad strategy on my part in when to
    change,
    when to recharge?
     
    Anthony Buckland, May 30, 2004
    #1
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  2. Anthony Buckland

    Rick Guest

    Recharge them once a month, or at least every other month.

    Rick
     
    Rick, May 30, 2004
    #2
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  3. Anthony Buckland

    Bob Williams Guest

    I've heard that NiMH batteries lose about 2-3% of their charge/day.
    My own experience confirms this. Closer to 2% than 3%.
    Maybe it depends on how old the batteries are.
    I always give my spares a fresh charge before I go out on a shoot.
    Bob Williams
     
    Bob Williams, May 30, 2004
    #3
  4. I recharge mine before going out. This is especially important if you are
    using them in a flash unit. When they are freshly charged, the flash cycle
    time is noticeably shorter. The self-dishcarge rate seems to be higher with
    some of these than what is advertised/claimed. I notice a siginificant
    difference after 2 weeks of non-use. Four weeks makes a big difference and 2
    months means they are almost dead!
     
    Charles Schuler, May 30, 2004
    #4
  5. << Bad batteries, or bad strategy on my part in when to
    change,
    when to recharge? >>

    Anthony-

    You'll have to work it out by trial and error. Your batteries may be better or
    worse than others. I have four sets, some holding their charge longer, but all
    will self-discharge given enough time.

    I find that it is necessary to recharge my spare NiMH batteries every two
    weeks. After three or four weeks, there is a good chance they will fail almost
    immemiately.

    It has become such a hassle, I've switched to using expendable Lithium
    batteries where possible. It is somewhat more expensive, but they do not
    self-discharge.

    Fred
     
    Fred McKenzie, May 30, 2004
    #5
  6. Self-discharge in NiMHs is a function of temperature, which is bad news
    for chargers which roast your cells, leaving them ultra-hot for an hour
    or so after charging. Comparing a charger like this with a Delta-V
    trickle maintenance charger, I found that my Ansmann battery tester read
    up to the 75 per cent (over 'full') mark on trickle charged cells (cool)
    and rarely over zero (full) on 'hot' cells after cooling down.

    Stick your NiMH cells in the fridge along with your film, and they will
    hold their charge.

    David
     
    David Kilpatrick, May 30, 2004
    #6
  7. I recharge my batteries, including the ones in the camera, at least once
    a month. Unlike the NiCads you can recharge them as often as you like. Of
    course it is best to have a smart charger (generally having a separate
    indicator light for each cell, rather than one for each pair of cells)
    helps.
     
    Joseph Meehan, May 31, 2004
    #7
  8. Anthony Buckland

    Lazarus Long Guest

    I recently discovered two packs I have that contain NiMH cells that
    held at least some of their charge for very nearly a year. I can't
    say how much charge, I do know it was enough to confirm operation of
    the equipment. Each pack contains 6 AA cells. YMMV

    I recharged both packs at that time.
     
    Lazarus Long, May 31, 2004
    #8
  9. There is quite a bit of variation in the quoted shelf life of charged
    NiMH batteries. Estimates of 1% charge loss/day can be found and also
    1 to 3 months. My own practice is much the same as Anthony Buckland.
    I assume one month shelf life but, if possible, I try to recharge
    before using. I have found this to work reasonably well both for
    digital cameras and my cordless computer mouse.
     
    James Silverton, May 31, 2004
    #9
  10. I routinely recharge all my NiMH batteries after three weeks, if they
    haven't been used.
     
    Marvin Margoshes, May 31, 2004
    #10
  11. Thanks to you and all the other posters. I will adopt a regular recharging
    schedule bases on your collective experiences.
     
    Anthony Buckland, May 31, 2004
    #11
  12. Anthony Buckland

    Ron Hunter Guest

    No less often than monthly, and only the day before you plan to do
    extensive shooting. And if possible, carry a disposable lithium battery
    set for emergency use.
     
    Ron Hunter, Jun 6, 2004
    #12
  13. Anthony Buckland

    FredBillie Guest

    << From: Ron Hunter
    Date: Sun, Jun 6, 2004 3:03 PM
    Message-id: <>

    No less often than monthly, and only the day before you plan to do
    extensive shooting. And if possible, carry a disposable lithium battery
    set for emergency use.Maybe Anthony should consider the 15 minute Rayovac charger. Use this for my
    wife’s iPod and it works great.
     
    FredBillie, Jun 7, 2004
    #13
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