NIMH (rechargeable) and Alkaline non rechargeable

Discussion in 'Digital Cameras' 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
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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
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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
  4. 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
  5. 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
  6. Pebble

    Paul Heslop Guest

    Clears a few things up for me :O)
    Paul Heslop, Jan 18, 2007
  7. 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
  8. 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
  9. 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'
    ray, Jan 18, 2007
  10. 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
  11. 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?
    SimonLW, Jan 18, 2007
  12. 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
  13. 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 Martindale, Jan 18, 2007
  14. Pebble

    ASAAR Guest

    One would think so, but that's not entirely the case. MagLites
    specify a working voltage range, and while alkalines start out with
    a higher voltage, through most of the battery's life the voltage
    will be higher using NiMH batteries. This partially depends on how
    the lights are used, and alkalines might appear to do a little
    better if they're used for very short periods, since the voltage
    "rebounds" when turned off, and for a short while after it is turned
    on again, the voltage (and the brightness) will be a bit greater
    than when it was turned off. If used for more than several minutes
    at a time, alkaline voltages will noticeably sag. This is what I
    like about MagLite's new LED lights. The lights (at least the one
    I've used) stay bright and has a very white color (without the
    bluish cast many LED lights have) even when the batteries aren't
    fresh. With filament bulbs, flashlights, whether MagLites or other
    brands, the light is bright and relatively white only with very
    fresh batteries. Throughout most of their lives, the light output
    gets weaker and weaker, and the color shifts from moderately white
    to a yellowish cast. The working voltage range I mentioned, is only
    specified for the non-LED MagLites. I couldn't find similar data
    for the LED lights. MagLite sells several types of bulbs for their
    flashlights. Some are more efficient than others, not only being
    brighter, but also last slightly longer per set of batteries, if I
    recall correctly. MagLite also sells replacement LED bulb modules
    for their traditional models, but only for the C and D cell sizes,
    not for the Solitaire and Mini models. What surprised me is that
    the LED light can focus the beam the way traditional MagLites do. I
    assume that this would also be true for older lights where the LED
    modules are installed. The LED MagLites, btw, still include a spare
    filament bulb in the base/end cap.

    I think that that was mainly a problem with NiCad batteries used
    in cheap flashes that have no protective circuitry. It's not just
    that they have very little internal resistance, which allows the
    flash capacitor to be charged more quickly, overheating the flash
    tube and other parts of the unit, but that (I believe) the NiCad
    cells themselves, due to their chemistry, produce more heat than
    other battery types. Better designed flash units allow only a
    certain number of flashes within a predetermined period before they
    stop operating temporarily (like from 15 to 30 minutes), allowing
    the flash unit to cool off to a safe operating temperature.

    It would be nice if manufacturers stated why certain things are
    recommended, allowed or prohibited. The way you use the Petzl is
    wise, since although LED lights could be designed to prevent cell
    reversal, my guess is that most aren't.

    That's odd. I almost always have a MagLite Solitaire in my pocket
    and it has never accidentally turned on. It's only out of habit,
    and I should have replaced it with something like a cheap Garrity
    LED light (also single AAA) that performs much better. The only
    advantage the Solitaire has is size. It's more compact, since it
    doesn't flare out to a larger diameter at the "light" end. The
    lights that cause me problems are the ones that although they have
    very high quality pushbutton switches, the switches require only a
    very light pressure to turn on. I noticed this one evening when on
    taking the light out of a roomy coat pocket, noticed only a very
    faint glow from the light's Luxeon LED. This model uses 3 AAA
    cells, and at least it only wasted the 3 alkalines. If rechargeable
    cells had been used, they probably would have needed to RIP. :)

    Sears sells some Craftsman lights (2C, 3D and 4AA models) that
    have 3 differently colored LEDs to help indicate battery voltage.
    But they'd really be useful if used for voltage regulated lights.
    In the Sears lights, the brightness of the lights themselves provide
    a better indication of the battery voltage than the LEDs. I
    replaced the filament bulb in one of the 4AA models with an LED bulb
    removed from another similar 4 AA light, and the green LED (that
    indicates high voltage) seems to be the only one that ever lights,
    even doing so when the batteries aren't particularly fresh. :)

    Yep, and these lights are usually part of a "pool", where the cop,
    fireman, etc. doesn't worry about taking care of the lights, which
    are typically charged, maintained and periodically tested by someone
    else. He/she just picks up a freshly charged light before heading
    out for the shift. These lights (LED and otherwise) are advertised
    as being useful as "weapons", since the brightness is high enough to
    temporarily incapacitate whoever is unwise enough to look into the
    light. The dim glow from dying alkalines just isn't the same. <g>
    ASAAR, Jan 19, 2007
  15. Pebble

    Paul Heslop Guest

    I wonder if the warning is international? I really think I'm probably
    just too lazy to look closely at stuff like flashlights, and as a rule
    I tend to keep my NIMH just for the cameras, but I'll have to have a
    look see next time I purchase something like this.
    good grief. We had a lot of problems with two cordless phones
    recently. when packing them to send them back I noted that they had
    quite weak NiCd batteries which kind of surprised me as i expected
    NiMh at least. Even after a complete overhaul they lasted only a few
    more weeks... wonder if the batteries could have contributed to their
    Now there's something I haven't taken a look at closely. personally
    for those things, if I bought them I'd want rechargeable anyway so
    they'd probably be NiCd at least.
    Strangely we have only just begun buying flashlights... must be
    something to do with being over 50 :O)
    Paul Heslop, Jan 19, 2007
  16. Pebble

    Paul Heslop Guest

    :O) We're sorry, we won't do it again
    Paul Heslop, Jan 19, 2007
  17. Pebble

    John Turco Guest

    ASAAR wrote:

    Hello, ASAAR:

    I've bought third-party ("Nite Ize, Inc.") 3-LED/reflector upgrade
    kits, intended for MagLite's AA flashlights.

    (Haven't installed any of them, yet, incidentally.)

    The Solitaire is a very cute and capable puppy, and I formerly carried
    one, on my keychain; I prefer the even smaller "no name" LED units, now.


    I replaced a regular bulb with an LED, in a "dollar store" (2 AA)
    clip-on light. Along with a tiny version (taking button cells), I
    use it when working inside my computer.

    Quite handy, indeed!

    A MagLite "D" would be a rather formidable "weapon" (the 4-cell model,
    especially), if wielded as a club. ;-)

    John Turco <>
    John Turco, Jan 21, 2007
  18. Pebble

    ASAAR Guest

    I got one of them several months ago, tried to install it in a
    very old Mini and it's ok, but if MagLite comes out with their own,
    it'll probably be much nicer - probably with regulated voltage like
    the C and D cell models.

    Do you know Buster Brown or his dog Tige? :)

    No thanks, I don't need to join that club. I've got the 3 D cell
    model, and the LED maintains high output so much longer than the
    bulb models that I think the 2 or 3 C-cell version would be better.
    I'd like to see a 4 D cell MagLite toss added to the Olympic Summer
    Games. If an event has to be dropped to make this possible, umm,
    how about making synchronized swimming disappear? :)

    By the way, Radio Shack has joined Sanyo and RayOVac in offering
    their own version of the Eneloop and Hybrid batteries. Unlike those
    two companies, RS hasn't given it a new name, saying only that these
    NiMH batteries are "precharged rechargeables". They have the same
    2,000 mAh capacity as the Eneloops, but RS charges a lot more for
    them, $20 for four. And for Ron if he's reading this, RS says that
    they're compatible with any standard NiMH charger. I wonder if
    their use of "standard" is designed to be a legal loophole?

    P.S. I just ran this reply through the newsreader's spell checker,
    and the first word it questioned was MagLite, with the first choice
    for a replacement being "Aglitter". :)
    ASAAR, Jan 21, 2007
  19. Pebble

    ASAAR Guest

    I'm sure that a typo crept in, and "hundreds or thousands of times
    longer" was intended.

    I agree. Manufacturers aren't inclined to do that. What they do
    instead is have their chargers indicate that the batteries are
    charged before the chargers have actually finished charging. Some
    of my old RayOVac chargers indicated that charging was complete at
    the point where the charge rate dropped from fast to slow (not quite
    a trickle charge), and at that point the cells were only 85% to 90%
    charged, and if left in the charger would complete charging several
    hours later.
    ASAAR, Jan 23, 2007
  20. Pebble

    ASAAR Guest

    Then don't think so hard! 365,000 qualifies as "hundreds of
    thousands" on the fairly low end, and if the batteries are used
    heavily enough to require a full charge every day of the year,
    they'd last for 1,000 years. I doubt that marketing departments
    addicted to the most hyperbolic copy would make such a claim. I
    trust that you see why I thought that you meant something else. <g>
    ASAAR, Jan 23, 2007
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