NIMH (rechargeable) and Alkaline non rechargeable

Discussion in 'Digital Photography' started by Pebble, Jan 18, 2007.

  1. Pebble

    Pebble Guest

    Hi all,
    Coming to grips with battery terminology. Have read lots of tutorials, opinions, grazed google posts and haven't really found out if one can put charged NIMH batteries in the place of non rechargable Alkaline batteries. I realise that voltage seems to be higher in Alkaline non rechargeables than the NIMH rechargeables. I think there is a loss of quality in signal for torches and radios and some other gear ??
    Trickle charge versus fast charge ??
    Thanks, all opinions welcome.
     
    Pebble, Jan 18, 2007
    #1
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  2. Pebble

    Paul Heslop Guest

    NIMH are often preferred over alkaline. I don't know if it is still
    true but there was a time where alkaline were not good for digital
    cameras etc, they drained quite quickly. The real problem with NIMH is
    they don't like to be standing around doing nothing. If you leave them
    for a while and come back to them they could be drained, so you have
    to kind of stay on top of them. Myself I usually have two sets, one in
    camera and one charged ready for replacing, but due to ill health I
    have hardly used my camera and on checking yesterday I found the
    batteries were drained, so popped in the replacements and they had
    drained too.
     
    Paul Heslop, Jan 18, 2007
    #2
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  3. Pebble

    Pebble Guest

    Thanks Paul,
    Still don't know if they are swappable though? My camera for instance takes alkaline OR NIMH, it mentions in the manual . Of course I use NIMH because the alkaline batteries send you broke. What I meant was if a radio, torch etc doesn't mention in the manual about using NIMH, just gives info like "insert 2 AA Alkaline batteries as shown in the diagram below" can NIMH be used in place of them?
     
    Pebble, Jan 18, 2007
    #3
  4. Hi Paul

    NiMH are a good replacement for Alkalines in applications that have a high
    drain rate (ie. require a releative large amount of power over a short
    period of time) or used constatly and recharged regulary. These applications
    include cameras, flashes, walkie talkies, digital music players, etc. In
    general NiMH batteries can be substituted for Alkaline batteries, check your
    owners manual of the item to know for sure.

    Alkaline batteries work best for items used infrequenly. Like emergency
    flashlights since they don't run down rapidly. Remember NiMH batteries will
    self discharge at 40% per month.

    For example, I use NiMH batteries in my camera flash. I use Alkaline
    batteries in my led flashlight that I keep in my truck.

    In general a trickle charge is better for the batteries and may be harder on
    your patence. I generally like to use a quick charger, currently a Duracell
    15 min. charger. It has a fan below the batteries so that they do not get
    hot.

    Hope this helps.

    William
     
    William Hathaway via PhotoKB.com, Jan 18, 2007
    #4
  5. Pebble

    Bob Salomon Guest

    No, some types of the latest NiMh AA cells come fully charged and will
    hold their charge for up to a year without use or recharging.

    Ansmann makes some cells that do this that are NiMh. Some companies
    maxes a similar claim for AA cells that are not NiMh. Panasonic, for
    instance.
     
    Bob Salomon, Jan 18, 2007
    #5
  6. Pebble

    Pebble Guest

    Thanks William and Paul,
    I've never seen in a manual "don't use NIMH" so I suppose is OK. I've got a radio that takes Alkaline batteries and have substituded NIMH but have been told that they don't pick up signal quite so well, voltage issues or something. Haven't noticed this yet, but when I go bush (600 km from nearest pub!) I might then.
    Yeah, trickle charges are a pain, but I think they're probably better. I keep some charged and well sealed in the freezer, defrost when needed. Slows the self discharge down, apparently. Didn't know it was normally 40% per month though! Wow
    I'd say those latest NIMH that hold their charge for over a year would have a hefty price tag!
    Thanks for all your help.
     
    Pebble, Jan 18, 2007
    #6
  7. Pebble

    Paul Heslop Guest

    I think usually they recommend alkaline due to its having a long
    lasting effect, plus if I remember it rightly when they drain they
    don't ooze that gunk all over, so for torches etc they are much better
    than the old style battery. I am not sure that NIMH would last as long
    in a standard device as an alkaline but as long as you don't mix and
    match they should be fine.
     
    Paul Heslop, Jan 18, 2007
    #7
  8. Pebble

    Paul Heslop Guest

    Clears a few things up for me :O)
     
    Paul Heslop, Jan 18, 2007
    #8
  9. NIMH rechargeables. I think >there is a loss of quality in signal for
    torches and radios >and some other gear ??
    Well, since I got my orbit intelligent charger I use rechargeable batteries
    for the torch (mini mag lite)which istrunctions say explicitly *not* to use
    rechargeable batteries but I cannot understand why when the worst scenario
    would be a burnt out lamp (4 euros a set of two)so I am using NiMHs on
    it.(Except of course the digital camera kodak cx 7300-two nicd pairs)also
    the little radio I take at work-nicds too-(the same pair I use at my
    walkman).So, I think, anything that operates on alkalines can use NiMHs, and
    of course I won't suggest ignoring the manufacturer's instructions,but the
    savings are great....
     
    Tzortzakakis Dimitrios, Jan 18, 2007
    #9
  10. Pebble

    nick c Guest

    All my standard flashlights (torches)have NIMH batteries. The newer
    hi-powered flashlights are supposed to use li-ion batteries. I also use
    NIMH batteries in my portable radios, clocks, CD players, automatic lawn
    sprinkler system, home automatic heating/air conditioning thermostat,
    and just about anywhere alkaline batteries are called for. Exception
    would be where the manufacturer states NIMH batteries should not be
    used. I once read that notice for an article I bought but now I can't
    remember what that article was.
     
    nick c, Jan 18, 2007
    #10
  11. Pebble

    Paul Heslop Guest

    I don't think I have ever seen that notice on anything, but then again
    I might have just binned the instructions :O)
     
    Paul Heslop, Jan 18, 2007
    #11
  12. Pebble

    ray Guest

    I've not observed any real compatibility issues. IMHO the faster the
    charger, the shorter the ultimate life of the batteries, generally. That
    is probably not so much of an issue if you buy an upper line 'intelligent'
    charger.
     
    ray, Jan 18, 2007
    #12
  13. Pebble

    ASAAR Guest

    I also have never seen that notice, and as far as I can tell it's
    because the primary reason would be to avoid using NiMH cells in
    situations where they could easily become damaged, or where with
    some poorly designed electronic devices, the rapid voltage drop that
    occurs when one or two cells go flat could cause the loss of memory,
    such as radio presets, configuration settings in mp3 players, etc.

    Fortunately, many digital electronic devices will power off before
    battery damage can occur, but as I said, there are some devices
    where this doesn't hold true. For those, the normally higher cost
    of using alkaline batteries can be lower than NiMH batteries that
    become damaged after only a small number of charge cycles.

    Using NiMH batteries in analog devices can often be very bad for
    the life of the batteries, since they'll usually continue drawing a
    significant current long after one or more cells become depleted.
    With flashlights that use filament bulbs, the main danger would be
    if they were used unattended, such as letting a camp lantern stay on
    overnight. But in normal use, as soon as the first NiMH cell
    becomes exhausted, the light output would drop to such a low level
    (if there's any remaining light output at all), that the user would
    probably immediately turn of the light, thereby protecting the cells
    from damage.

    In my portable CD players that use only a single AA cell, there's
    little risk in using NiMH cells, and that's what I generally use.
    But in CD players that use at least two AA cells, if the player uses
    even a very small amount of current when powered off, NiMH cells can
    be damaged if they go for many weeks or months unattended. If the
    cells are recharged soon after going dead there's probably nothing
    to worry about. But if you catch it too late, there's a very good
    change that damage will occur. This may not be immediately
    realized, however since the damaged cells can usually still be
    charged, but they may have lost a considerable amount of capacity.
    If the CD player can then play for another 15 hours instead of the
    normal 40 hours per charge, most people may go for a *long* time
    (many charge cycles) before noticing that anything is amiss. These
    damaged cells may also be rejected by *some* smart chargers, even
    though they are not entirely useless. Out of several smart
    chargers, I only have one that can be counted on to be able to
    charge these slightly damaged NiMH cells.

    As for the "newer hi-powered flashlights" that Nick mentioned, the
    only ones I'm aware of that use rechargeable batteries are models
    used by police, firemen, military, etc., and they tend to use
    proprietary NiCad or NiMH battery packs, not Li-Ion, and are usually
    very expensive, costing several hundreds of dollars. That's not to
    say that there aren't any Li-Ion models, but I haven't seen them.
    What Nick may be thinking of are the multiple watt, *very* bright
    LED lights that are designed to use non-rechargeable lithium
    batteries. And it's not that they need to use lithium batteries, as
    several manufacturers are now making high powered LED lights that
    use alkaline batteries. The best ones use voltage regulators, so
    that even as the alkaline battery voltages drop, the light output
    doesn't fall off. I got one of the new MagLites about 6 months ago
    and its output is today just as bright as they day I put the
    batteries in it. These D cell batteries were removed from another
    device because for it, the battery voltage was getting very low. :)
     
    ASAAR, Jan 18, 2007
    #13
  14. Pebble

    SimonLW Guest

    I saw a Pop Photo avert for these "Enerloop" batteries by Sanyo a few months
    back. I guess Rayovac also has these slow self discharge NiMH batteries. The
    quick self discharge problem is the only thing keeping me from adopting to
    them. Any major retailer carrying them yet?
    -S
     
    SimonLW, Jan 18, 2007
    #14
  15. Pebble

    Paul Rubin Guest

    Ritz Camera has Eneloop.
     
    Paul Rubin, Jan 18, 2007
    #15
  16. Pebble

    ASAAR Guest

    They're available from several sources. I think that Walmart and
    Ritz have been mentioned here before as having Eneloops. For
    several months Circuit City has been selling Eneloops as well as
    RayOVac's version, which they call Hybrid batteries. I've been
    using both brands, and so far so good.
     
    ASAAR, Jan 18, 2007
    #16
  17. Pebble

    tnom Guest

    Ritz camera and Circuit City
     
    tnom, Jan 18, 2007
    #17
  18. Pebble

    y_p_w Guest

    Mag Lite flashlights specifically don't recommend the use of
    rechargeable batteries. I think part of the reason is that a NiMH
    cell starts off at 1.4V (at best) or maybe 1.3V a day after being
    charged. A fresh alkaline cell starts off at 1.6V. A light on a
    fresh set of alkalines will be brighter as a result. These are not
    high-drain devices where NiMH is more efficient.

    The bulbs might also be designed with the internal resistance of
    alkalines in mind to maximize life. Just a thought. I've heard of
    some older camera flashes that would die when NiMH batteries
    were used because they were designed to use the internal resistance
    of alkalines as a current limiter.

    I have a Petzl LED headlamp, and the instructions state that
    NiMH rechargeables are acceptable. I'll almost always recharge
    them quickly before cell reversal can happen.
    I used NiMH AAAs in a Mag Lite Solitaire. Bad idea. It didn't mean
    cell reversal but constantly deep discharging the battery when the
    cap turned on in my pocket killed the capacity quickly.
    Low battery warning and/or protection diodes would help. That
    would require circuitry that would cost too much for the average
    flashlight.
    Anything that expensive probably uses protection circuits to keep
    the batteries from cell reversal or deep discharge. Many have low
    battery indicators. Frankly it's a better idea because they can be
    topped off every night with a reasonable expectation of charge life.
    That would compare with alkaline cells that are left in until they run
    out, and without having a good idea how much battery life is there.
    Of course there could be something like a regular schedule where
    alkalines are replaced every other day, but that's rather wasteful.
     
    y_p_w, Jan 18, 2007
    #18
  19. I've seen it in two places: electronic flashes and handheld radio
    battery packs. In both cases, it's because NiCd and NiMH cells have
    much lower internal resistance, and thus can deliver much more current
    into a low-resistance load, than alkalines can.

    If you short an alkaline cell, you'll get a few amps of current flowing -
    enough to make the cell get warm but not much more. If you short an AA
    NiCd cell, the current may be 10 amps or more. This is enough to damage
    the cell internally, melt smaller-gauge wire, and if it continues the
    cell may heat up rapidly enough to explode.

    Many handheld radio transmitters are powered by battery packs containing
    NiCd or NiMH cells, and they always include a fuse or circuit breaker of
    some sort to protect the pack from exploding or catching fire if the
    terminals are accidentally shorted. Some manufacturers also sell AA
    battery packs for emergencies, and these packs are usually just a
    battery holder without any protective devices. The manufacturer's
    manual says to use alkalines only, because alkalines are safe without
    external circuit breakers. NiMH cells will fit fine and work well, but
    there is a fire hazard when you do it.

    In the case of electronic flashes, there were once some flashes that
    depended on the battery internal resistance to limit the battery current
    during flash recharge. If you installed NiCd cells instead of alkalines
    (this was a long time ago), the current increased beyond the limits of
    the electronics, and the flash died.

    Dave
     
    Dave Martindale, Jan 18, 2007
    #19
  20. Pebble

    Ron Hunter Guest

    Some poorly designed (read that CHEAP) devices use the internal
    resistance in the Alkaline batteries as a limiter of the current the
    circuitry can draw. Using NIMH batteries in such a device might cause
    damage to the device, (and to the user)!
    Use of NIMH batteries in more complex, and well-designed, devices is
    usually preferable to alkaline batteries due to cost factors.
    Generally, using the batteries recommended by the device manufacturer is
    the best choice. NIMH batteries, most of which have high values of
    'self-discharge' aren't generally good candidates for devices which
    aren't used often, or which are used continuously over long periods
    (clocks).
    Unless you really like changing batteries, and charging them, I don't
    recommend NIMH batteries for clocks, thermostats, or flashlights
    (torches). Multi-cell devices without electronic shutoff can cause
    reverse polarity in NIMH batteries, damaging the battery.

    Chargers recommended by the battery manufacturer are usually the best
    choice. Either a trickle charger, or a smart charger than charges each
    battery separately are best.
     
    Ron Hunter, Jan 19, 2007
    #20
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