Nimh battery not as full as alkaline's?

Discussion in 'Digital Photography' started by JakeC, Feb 11, 2007.

  1. JakeC

    JakeC Guest

    Hi all,

    I just bought a two sets of 4 Energizer 2500mAh batteries yesterday. One
    set came with a charger. I used that charger to charge both of the sets.
    It took nine hours to finish charging each set (as indicated by the
    turning off of the LED light on the charger and the warmth of the
    batteries). Then I used a small, handy battery tester to see how "full"
    the batteries are. Sadly my tester says they're just above "replace". I
    remembered I also tested one of the sets right off the package and I got
    the same indication. It seems like the charging has no effect on the
    batteries. I also put a pair of the batteries into a flash light. It
    turned out that the light was dimmer than that came out with the pair of
    the no-name alkaline batteries originally sitting in that flash light.

    Is there something wrong with the charger? Shouldn't my tester have its
    pointer moving all the way across the "good" area of the tester, just
    like any new batteries will make it to and show that the batteries are
    full? Do I need to re-charge the batteries?


    Thanks in advance for your input.



    JC
     
    JakeC, Feb 11, 2007
    #1
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  2. JakeC

    Pete D Guest

    You cannot use the same tester for alkaline and NiMh, alkaline have a
    nominal voltage of 1.5 volts, NiMh have a nominal voltage of 1.2 volts.

    "JakeC" <> wrote in message
    news:59Kzh.943347$R63.145309@pd7urf1no...
    > Hi all,
    >
    > I just bought a two sets of 4 Energizer 2500mAh batteries yesterday. One
    > set came with a charger. I used that charger to charge both of the sets.
    > It took nine hours to finish charging each set (as indicated by the
    > turning off of the LED light on the charger and the warmth of the
    > batteries). Then I used a small, handy battery tester to see how "full"
    > the batteries are. Sadly my tester says they're just above "replace". I
    > remembered I also tested one of the sets right off the package and I got
    > the same indication. It seems like the charging has no effect on the
    > batteries. I also put a pair of the batteries into a flash light. It
    > turned out that the light was dimmer than that came out with the pair of
    > the no-name alkaline batteries originally sitting in that flash light.
    >
    > Is there something wrong with the charger? Shouldn't my tester have its
    > pointer moving all the way across the "good" area of the tester, just like
    > any new batteries will make it to and show that the batteries are full? Do
    > I need to re-charge the batteries?
    >
    >
    > Thanks in advance for your input.
    >
    >
    >
    > JC
     
    Pete D, Feb 11, 2007
    #2
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  3. JakeC

    Cgiorgio Guest

    "JakeC" <> schrieb im Newsbeitrag
    news:59Kzh.943347$R63.145309@pd7urf1no...
    > Hi all,
    >
    > Is there something wrong with the charger? Shouldn't my tester have its
    > pointer moving all the way across the "good" area of the tester, just like
    > any new batteries will make it to and show that the batteries are full? Do
    > I need to re-charge the batteries?
    >
    >
    > Thanks in advance for your input.
    >
    >
    >
    > JC


    Nope.
    Alkaline cells have a nominal output voltage of 1.5 Volts, without a load a
    new alkaline has nearly 1.6 Volts between its terminals. A NiMH cell has a
    nominal voltage of 1.2 Volts, when fully charged they will have around 1.35
    Volts with no load connected.

    In high current applications (like in a digital camera) the output voltage
    of Alkalines drops much faster than that of NiMH's, because they have higher
    internal resistance (Ohm's law). Most cheap testers do not simulate a high
    current load (that would also unnecessarily shorten the life of primary
    cells).

    It is a good idea to use your new rechargeable batteries until your camera
    shows a low battery warning and to recharge them only then. Many NiMH cells
    reach full capacity only after a few full charge / discharge cycles. After
    that it is sufficient to do a full discharge / charge cycle about every 3 -
    6 months.
     
    Cgiorgio, Feb 11, 2007
    #3
  4. JakeC

    Just D Guest

    "Cgiorgio"
    > It is a good idea to use your new rechargeable batteries until your camera
    > shows a low battery warning and to recharge them only then. Many NiMH
    > cells reach full capacity only after a few full charge / discharge cycles.
    > After that it is sufficient to do a full discharge / charge cycle about
    > every 3 - 6 months.


    We discussed that here a month or two ago and found that the full discharge
    will kill the battery forever. So that's a very good advice that you just
    gave! Roll back to the history and try to find the previous thread before
    you give such an advice one more time.

    Just D.
     
    Just D, Feb 11, 2007
    #4
  5. JakeC

    Cgiorgio Guest

    "Just D" <> schrieb im Newsbeitrag
    news:UsKzh.6048$...
    > We discussed that here a month or two ago and found that the full
    > discharge will kill the battery forever. So that's a very good advice that
    > you just gave! Roll back to the history and try to find the previous
    > thread before you give such an advice one more time.
    >
    > Just D.
    >

    Please learn to read before criticizing posts. Discharging until a battery
    warning appears and deep discharging are completely different meanings.
    Usually a battery warning will appear around 1.05 Volts cell voltage which
    is far from zero Volts (around 1050 milliVolts to be precise). If you want
    to learn a bit about different battery types, you could read the material at
    www.batteryuniversity.com . While latest developments are not taken into
    account in that information, the basic information there is still valid.
     
    Cgiorgio, Feb 11, 2007
    #5
  6. JakeC

    ASAAR Guest

    On Sun, 11 Feb 2007 19:30:09 GMT, JakeC wrote:

    > I just bought a two sets of 4 Energizer 2500mAh batteries yesterday. One
    > set came with a charger. I used that charger to charge both of the sets.
    > It took nine hours to finish charging each set (as indicated by the
    > turning off of the LED light on the charger and the warmth of the
    > batteries). Then I used a small, handy battery tester to see how "full"
    > the batteries are. Sadly my tester says they're just above "replace". I
    > remembered I also tested one of the sets right off the package and I got
    > the same indication. It seems like the charging has no effect on the
    > batteries. I also put a pair of the batteries into a flash light. It
    > turned out that the light was dimmer than that came out with the pair of
    > the no-name alkaline batteries originally sitting in that flash light.
    >
    > Is there something wrong with the charger? Shouldn't my tester have its
    > pointer moving all the way across the "good" area of the tester, just
    > like any new batteries will make it to and show that the batteries are
    > full? Do I need to re-charge the batteries?


    There's probably nothing wrong with the batteries. Fresh alkaline
    batteries start out at a voltage just above 1.5v and just charged
    NiMH (and NiCD) batteries measure slightly above 1.2 volts. So
    your tester and flashlight are both showing you the expected
    results. But as both battery types are used, the voltages will
    drop, and if you have two flashlights running simultaneously, one
    powered by alkalines and the other by your NiMH cells, before too
    long the alkaline powered flashlight will become much dimmer than
    the one powered by the NiMH cells. When used in devices that use
    very, very small amounts of energy, both battery types will last
    about the same amount of time. Cameras, on the other hand require
    moderate to large amounts of power, and for these battery hungry
    devices, alkaline AA cells are completely outperformed by high
    capacity NiMH cells, usually lasting twice as long in some recent
    cameras, and the difference can be much greater in older cameras.

    I have a battery tester app. that runs on my Palm PDA, and it's
    configurable, allowing several different battery types to be
    selected. Same goes for some electronic devices (usually radios)
    that have a switch to allow you to set it to "alkaline" or
    "rechargeable". This allows them to show a more accurate battery
    status than your voltage tester, which apparently is designed only
    for alkaline batteries. Some testers are cruder than others. For
    example, I have a small, inexpensive tester that uses the same
    resistive load for all battery sizes, AAA, AA, C and D. Because the
    smaller batteries have higher internal resistances, fresh, smaller
    batteries won't move the needle as high as fresh, larger batteries,
    even though they should appear the same. Better testers have ways
    to present different resistive loads to different size batteries,
    making them a little bit more accurate. The bottom line is that
    your battery tester can provide misleading results unless you know
    more about how batteries really perform. If you're interested,
    there are some pretty good charts on the battery data sheets that
    can be downloaded from Energizer's website. They're PDF files.
     
    ASAAR, Feb 11, 2007
    #6
  7. JakeC

    Just D Guest

    "Cgiorgio"
    > Please learn to read before criticizing posts. Discharging until a battery
    > warning appears and deep discharging are completely different meanings.
    > Usually a battery warning will appear around 1.05 Volts cell voltage which
    > is far from zero Volts (around 1050 milliVolts to be precise). If you want
    > to learn a bit about different battery types, you could read the material
    > at www.batteryuniversity.com . While latest developments are not taken
    > into account in that information, the basic information there is still
    > valid.


    Sorry if I probably wasn't correct or polite writing my previous message.
    Just look what you wrote: "Many NiMH cells reach full capacity only after a
    few full charge / discharge cycles. After that it is sufficient to do a full
    discharge / charge cycle about every 3 - 6 months." It would definitely
    mislead me if I just read about complete full discharge after 3-6 months and
    I'd follow this advice for sure using whatever is available, standard
    discharger inside the charger, the device where this battery works, etc. For
    example very good advice I got from the Micron laptop manual. It recommended
    to completely discharge the battery at least one time every half-a-year. To
    do that COMPLETELY I need to open the BIOS settings and leave the laptop
    working with this battery until it shuts down, actually dies. Very good
    advice completely killed the battery much sooner that it could happen. I
    assume that some of the smart rechargers are able to understand where is the
    killing level of the battery but we need to be careful giving these advices,
    not all batteries will survive after complete discharge.

    Just D.
     
    Just D, Feb 11, 2007
    #7
  8. JakeC

    MG Guest

    > I just bought a two sets of 4 Energizer 2500mAh batteries yesterday.

    I bought a set of Energizer 2500 batteries a while ago. They are the worst
    batteries I have. Their discharge rate when not in use is very high. I
    prefer the ageing 1700mAh batteries that came with my camera to the
    Energizers. I won't be buying Energizers again.

    MG
     
    MG, Feb 11, 2007
    #8
  9. JakeC wrote:
    > Hi all,
    >
    > I just bought a two sets of 4 Energizer 2500mAh batteries yesterday.
    > One set came with a charger. I used that charger to charge both of
    > the sets. It took nine hours to finish charging each set (as
    > indicated by the turning off of the LED light on the charger and the
    > warmth of the batteries). Then I used a small, handy battery tester
    > to see how "full" the batteries are. Sadly my tester says they're
    > just above "replace". I remembered I also tested one of the sets
    > right off the package and I got the same indication. It seems like
    > the charging has no effect on the batteries. I also put a pair of the
    > batteries into a flash light. It turned out that the light was dimmer
    > than that came out with the pair of the no-name alkaline batteries
    > originally sitting in that flash light.
    > Is there something wrong with the charger? Shouldn't my tester have
    > its pointer moving all the way across the "good" area of the tester,
    > just like any new batteries will make it to and show that the
    > batteries are full? Do I need to re-charge the batteries?
    >
    >
    > Thanks in advance for your input.
    >
    >
    >
    > JC


    As you know from the other post, there is nothing wrong. However I have
    a suggestion. The battery charger is a very important part of the life of
    those batteries. You wrote: "turning off of the LED light on the charger "
    In general those chargers with as single LED charge indicator is charging
    all the cells the same way. Since cells are never exactly the same some
    really need a little more and some a little less. Those chargers that
    tailor their charge for each cell (generally have a light for each cell)
    will usually give better results.

    --
    Joseph Meehan

    Dia 's Muire duit
     
    Joseph Meehan, Feb 11, 2007
    #9
  10. JakeC

    ASAAR Guest

    On Sun, 11 Feb 2007 13:15:40 -0700, Just D wrote:

    > I assume that some of the smart rechargers are able to understand where is
    > the killing level of the battery but we need to be careful giving these advices,
    > not all batteries will survive after complete discharge.


    As far as I can tell, all of the battery chargers that have
    discharge circuits only discharge until individual cells have
    dropped to about 1.0 volts. At that point, unlike alkalines which
    will still have nearly half of the energy of fresh alkalines
    remaining, rechargeables will be about 100% depleted, so it's
    unnecessary (and unwise) to discharge them any further. My Fuji is
    apparently one of the few camera that has a menu item that allows
    the camera to discharge NiMH batteries. Of course the manual says
    that it shouldn't be used for alkaline batteries, but I'm sure that
    at least a few naive Fuji owners must have tried that. <g>
     
    ASAAR, Feb 11, 2007
    #10
  11. JakeC

    Just D Guest

    "Cgiorgio"
    > Many NiMH cells reach full capacity only after a few full charge /
    > discharge cycles. After that it is sufficient to do a full discharge /
    > charge cycle about every 3 - 6 months.

    ....
    > If you want to learn a bit about different battery types, you could
    > read the material at www.batteryuniversity.com


    Let's follow this advice together. Actually I read it couple months ago when
    found the link in this NG.

    http://www.batteryuniversity.com/partone-16.htm
    "Among battery chemistries, nickel-cadmium is least affected by repeated
    full discharge cycles. Several thousand charge/discharge cycles are
    possible. This is why nickel-cadmium performs well on power tools and
    two-way radios that are in constant use. nickel-metal-hydride is less
    durable in respect to repeated deep cycling."

    My special thanks to Micron doc-writers killed many laptop batteries with
    their cool manual when I followed their advice several years ago.

    Just D.
     
    Just D, Feb 11, 2007
    #11
  12. JakeC

    Just D Guest

    "ASAAR"
    > unnecessary (and unwise) to discharge them any further. My Fuji is
    > apparently one of the few camera that has a menu item that allows
    > the camera to discharge NiMH batteries. Of course the manual says
    > that it shouldn't be used for alkaline batteries, but I'm sure that
    > at least a few naive Fuji owners must have tried that. <g>


    That's nice! And you're right, the rifle visible on the scene in the very
    beginning of the action will definitely must shoot before the action is
    ended. :) That's the basic theatre rule.

    Just D.
     
    Just D, Feb 11, 2007
    #12
  13. JakeC

    JakeC Guest

    Joseph Meehan wrote:

    >
    > As you know from the other post, there is nothing wrong. However I have
    > a suggestion. The battery charger is a very important part of the life of
    > those batteries. You wrote: "turning off of the LED light on the charger "
    > In general those chargers with as single LED charge indicator is charging
    > all the cells the same way. Since cells are never exactly the same some
    > really need a little more and some a little less. Those chargers that
    > tailor their charge for each cell (generally have a light for each cell)
    > will usually give better results.



    I take that to mean I'd better get a better charger then.

    Thank you all for responding.

    From what I read, it seems to me alkaline Vs Nimh is like Sprinter Vs
    Marathoner. One is fast and powerful but doesn't last very long, and the
    other is not as powerful but last much longer. Judging by my flashlight
    test it seems to be so. How's that analogy?
     
    JakeC, Feb 11, 2007
    #13
  14. JakeC

    Just D Guest

    "JakeC"
    > From what I read, it seems to me alkaline Vs Nimh is like Sprinter Vs
    > Marathoner. One is fast and powerful but doesn't last very long, and the
    > other is not as powerful but last much longer. Judging by my flashlight
    > test it seems to be so. How's that analogy?


    I'd say kamikaze VS. pilots.

    Just D.
     
    Just D, Feb 11, 2007
    #14
  15. JakeC

    Guest

    There's more to a battery than voltage. Your tester is only
    one dimensional as it can only display the batteries voltage.
    NIMH batteries by nature have a slightly lower voltage than
    alkaline's. If your tester could be three dimensional it would
    be able to measure the positive attributes of a NIMH battery.
     
    , Feb 11, 2007
    #15
  16. JakeC

    ray Guest

    On Sun, 11 Feb 2007 19:30:09 +0000, JakeC wrote:

    > Hi all,
    >
    > I just bought a two sets of 4 Energizer 2500mAh batteries yesterday. One
    > set came with a charger. I used that charger to charge both of the sets.
    > It took nine hours to finish charging each set (as indicated by the
    > turning off of the LED light on the charger and the warmth of the
    > batteries). Then I used a small, handy battery tester to see how "full"
    > the batteries are. Sadly my tester says they're just above "replace". I
    > remembered I also tested one of the sets right off the package and I got
    > the same indication. It seems like the charging has no effect on the
    > batteries. I also put a pair of the batteries into a flash light. It
    > turned out that the light was dimmer than that came out with the pair of
    > the no-name alkaline batteries originally sitting in that flash light.
    >


    I would imagine that is because fully charged alkaline batteries generate
    1.5 volts whereas fully charged NiMH batteries generate 1.25 volts - it's
    a different chemistry.

    > Is there something wrong with the charger? Shouldn't my tester have its
    > pointer moving all the way across the "good" area of the tester, just
    > like any new batteries will make it to and show that the batteries are
    > full? Do I need to re-charge the batteries?
    >
    >
    > Thanks in advance for your input.
    >
    >
    >
    > JC
     
    ray, Feb 11, 2007
    #16
  17. JakeC

    Adam Helberg Guest

    "JakeC" <> wrote in message
    news:59Kzh.943347$R63.145309@pd7urf1no...
    > Hi all,
    >
    > I just bought a two sets of 4 Energizer 2500mAh batteries yesterday. One set came
    > with a charger. I used that charger to charge both of the sets. It took nine hours
    > to finish charging each set (as indicated by the turning off of the LED light on
    > the charger and the warmth of the batteries). Then I used a small, handy battery
    > tester to see how "full" the batteries are. Sadly my tester says they're just above
    > "replace". I remembered I also tested one of the sets right off the package and I
    > got the same indication. It seems like the charging has no effect on the batteries.
    > I also put a pair of the batteries into a flash light. It turned out that the light
    > was dimmer than that came out with the pair of the no-name alkaline batteries
    > originally sitting in that flash light.
    >
    > Is there something wrong with the charger? Shouldn't my tester have its pointer
    > moving all the way across the "good" area of the tester, just like any new
    > batteries will make it to and show that the batteries are full? Do I need to
    > re-charge the batteries?
    >
    >
    > Thanks in advance for your input.
    >
    >
    >
    > JC


    The "tester" is likely a voltmeter (perhaps with a light load) and was likely
    calibrated for alkaline batteries, so naturally it will read low for NiMh since their
    voltage is lower. The NiMh are probably fully charged and hold as much charge as the
    alkaline.

    Adam
     
    Adam Helberg, Feb 11, 2007
    #17
  18. JakeC

    Cgiorgio Guest

    For
    > example very good advice I got from the Micron laptop manual. It
    > recommended to completely discharge the battery at least one time every
    > half-a-year. To do that COMPLETELY I need to open the BIOS settings and
    > leave the laptop working with this battery until it shuts down, actually
    > dies. Very good advice completely killed the battery much sooner that it
    > could happen. I assume that some of the smart rechargers are able to
    > understand where is the killing level of the battery but we need to be
    > careful giving these advices, not all batteries will survive after
    > complete discharge.
    >
    > Just D.
    >


    What you read in your laptop's manual was basically good advice, but the
    recommended time interval was too long. By performing a lot of partial
    discharge / charge cycles, differences in capacity between the individual
    cells are accentuated. Some of the cells are more prone to memory effect
    than others, after six months it was enough that one or two cells had lost
    so much of their capacity that they were driven into reverse charge during
    that discharge. Laptop NiMH battery packs used between 8 and 12 cells in
    series, which makes it quite difficult to accurately control.

    With just two or four cells in series as used in digital cameras, the chance
    of reversing a cell is much lower. I do not know of any current camera using
    sealed multi-cell NiMH packs, single cells can be handled individually by an
    intelligent charger. It is still advisable to always use the same batteries
    together.
     
    Cgiorgio, Feb 11, 2007
    #18
  19. JakeC

    Daryl Bryant Guest

    "Just D" <> wrote in message
    news:UsKzh.6048$...
    > "Cgiorgio"
    > > It is a good idea to use your new rechargeable batteries until your

    camera
    > > shows a low battery warning and to recharge them only then. Many NiMH
    > > cells reach full capacity only after a few full charge / discharge

    cycles.
    > > After that it is sufficient to do a full discharge / charge cycle about
    > > every 3 - 6 months.

    >
    > We discussed that here a month or two ago and found that the full

    discharge
    > will kill the battery forever. So that's a very good advice that you just
    > gave! Roll back to the history and try to find the previous thread before
    > you give such an advice one more time.


    That's not what he's saying...he meant that you should discharge the battery
    using a battery discharger, and their is such a thing, and no it won't
    discharge the batteries fully!!! I always discharge all my rechargeable
    batteries, once about every week. I use a standard pulse charger to
    charge/discharge all my batteries. You can use to charge a lead acid battery
    as well. Using a pulse charger I have taken a completely dead lead acid
    battery and revived it - several times!! For a good Pulse charger, expect
    to pay $100.00 US.
     
    Daryl Bryant, Feb 12, 2007
    #19
  20. JakeC

    Daryl Bryant Guest

    "Cgiorgio" <> wrote in message
    news:eqo4fs$g2j$00$-online.com...
    > For
    > > example very good advice I got from the Micron laptop manual. It
    > > recommended to completely discharge the battery at least one time every
    > > half-a-year. To do that COMPLETELY I need to open the BIOS settings and
    > > leave the laptop working with this battery until it shuts down, actually
    > > dies. Very good advice completely killed the battery much sooner that it
    > > could happen. I assume that some of the smart rechargers are able to
    > > understand where is the killing level of the battery but we need to be
    > > careful giving these advices, not all batteries will survive after
    > > complete discharge.
    > >
    > > Just D.
    > >

    >
    > What you read in your laptop's manual was basically good advice, but the
    > recommended time interval was too long. By performing a lot of partial
    > discharge / charge cycles, differences in capacity between the individual
    > cells are accentuated. Some of the cells are more prone to memory effect


    I remember when NiMH's first came out - They hiped a memory-free
    status...The memory effect is not as bad as a NiCd's memory loss.

    > than others, after six months it was enough that one or two cells had lost
    > so much of their capacity that they were driven into reverse charge during
    > that discharge. Laptop NiMH battery packs used between 8 and 12 cells in
    > series, which makes it quite difficult to accurately control.
    >
    > With just two or four cells in series as used in digital cameras, the

    chance
    > of reversing a cell is much lower. I do not know of any current camera

    using
    > sealed multi-cell NiMH packs, single cells can be handled individually by

    an
    > intelligent charger. It is still advisable to always use the same

    batteries
    > together.
    >
    >
     
    Daryl Bryant, Feb 12, 2007
    #20
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