Lithium Ion hold significantly more charge than NiMH?

Discussion in 'Digital Photography' started by void, Nov 21, 2006.

  1. void

    void Guest

    I was in Best Buy today, looking at the Canon A540 and SD600. The A540
    takes 2 AA batteries, and the SD600 takes one of those rectangular Lithium
    Ion batteries. A couple of Best Buy employees said that the Lithium Ion
    battery holds a lot more charge than NiMH batteries. They said the SD600
    camera would be able to take around 200 shots before the battery ran out,
    while the A540 would only be able to take around 30-40 shots before the
    batteries ran out.

    I am extremely skeptical of what they said. If what they said is true,
    then there is no reason why any camera on the market today would take AA
    batteries instead of the Lithium Ion battery.

    So were they right or wrong?
     
    void, Nov 21, 2006
    #1
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  2. void

    Pete D Guest

    Strictly speaking they are wrong, the NiMh batteries may well be larger in
    capacity but as the stored charge is used the voltage will drop and
    particularly in cameras this can be a problem, LIon batteries on the other
    hand should hold a higher voltage as the stored charge reduces and therefore
    may keep operating even though the stored charge is less.
     
    Pete D, Nov 21, 2006
    #2
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  3. void

    Paul Rubin Guest

    The practical answer is, it will burn through alkaline AA cells pretty
    fast (they're not built for the high current that a camera needs) but
    NiMH rechargeable AA cells will run it for a long time, at least as
    long as the small li ion packs. I have the A530 (similar to A540) and
    charge up the AA cells once in a while. I really like being freed
    from proprietary batteries.
     
    Paul Rubin, Nov 21, 2006
    #3
  4. LiIon batteries have about the same, or maybe a little less, amp hour
    rating as NiMH but at three times the voltage, half the weight, and with
    less self-discharge.

    The downside to LiIon batteries is that they're expensive and their life
    can be shorter than NiMH.


    http://en.wikipedia.org/wiki/Lithium_ion_battery
    http://en.wikipedia.org/wiki/NiMH
     
    Kevin McMurtrie, Nov 21, 2006
    #4
  5. Neither. Each battery has its advantages and disadvantages.

    NiMH AAs can be swapped out easily, and they're inexpensive to buy, but
    store less energy than the Li Ion batteries.

    Li Ion batteries are quite expensive, even if they are designed to be
    swapped out. But they do have a higher energy density.

    My camera is an A540. and it takes NiMH AAs. You can also put Alkaline
    batteries in this camera in a pinch, but they don't last too long. Takes
    non-rechargeable Lithium batteries also.
     
    Pat O'Connell, Nov 21, 2006
    #5
  6. void

    Paul Rubin Guest

    Nah. Total energy in the same volume is about the same. The lithium
    ion cells do weigh less. NiMH self-discharge varies with the cells.
    Lithium cells develop it too.
     
    Paul Rubin, Nov 21, 2006
    #6
  7. void

    Bill Guest

    They were wrong, but not for the reasons mentioned. The sales geeks
    got their info mixed up.

    Using Alkaline AA cells is a bad idea because they are not high
    current discharge capable like rechargeables, so they tend to work for
    only a few dozen shots before their voltage level drops enough that
    they appear dead to the camera. Allowing Alakaline cells to "rest" for
    a while may help get a few more shots, but they're simply a poor
    choice for high current devices like cameras.

    The Li-Ion and Ni-MH cells can produce higher current levels and the
    camera makes better use of their performance.
    No, strictly speaking they were RIGHT. Lithium-based batteries have a
    higher charge density per weight than any other rechargeable cell.

    The problem is the confusion with AA and rechargeables.
    I'm sorry but you're wrong again.

    Li-Ion discharge voltage also drops, but in a more steady drop (linear
    curve) than Ni-MH or Ni-Cad cells, which tend to dip, then level off,
    then drop off at the end of charge (stepped curve). Li-Ion drops
    steadily and smoothly as the charge level drops - they do not hold
    voltage levels while discharging at all.

    Please research battery technology from reputable sources before
    spreading incorrect information. We already have enough misinformation
    about technology as it is.

    I once had to do research into various battery technologies for a
    work-related contract purchase. If you want specific quotes, try
    places like:

    http://www.hardingenergy.com/

    http://www.electricitystorage.org/
     
    Bill, Nov 21, 2006
    #7
  8. void

    Pete D Guest

    Perhaps you should learn to interpret your infomation sources better. What I
    said still stands up.

    Cheers.

    Pete D
    NiMH Voltage

    The discharge voltage profile of a NiMH battery is considered “flat” (see
    Figure 3.7.2 C/10 Discharge

    Profile @ 25°C) and varies with the rate of discharge and temperature. As a
    fully charged battery is

    discharged the voltage begins at about 1.5 volts followed by a sharp drop to
    around 1.3 volts. The

    voltage remains between 1.3 to 1.2 volts for about 75% of the profile until
    a second sudden drop in

    voltage occurs as the useful capacity of the battery begins to deplete.



    Lithium Ion



    5.4 Rate Capability

    Table 5.4.1: Charge/Discharge Chemical Reactions

    Typical Performance Characteristics of Lithium Ion Batteries



    5.5 Discharge Characteristics

    At a constant current discharge rate, the lithium ion battery maintains a
    relatively flat voltage discharge profile

    with a steep decrease in the profile near the end of discharge. The battery
    should not be discharge to less than

    3.0 volts per battery.
     
    Pete D, Nov 21, 2006
    #8
  9. void

    SMS Guest

    The Best Buy employees are full of it. According to
    "http://www.dcresource.com/reviews/canon/powershot_a540-review/" the
    A540 is good for 360 shots, while the SD600 was rated at 160 shots.
    I wouldn't expect the employees of the big-box electronics retailers to
    know anything about the products they are selling, other than which
    products have the better spiffs.
    Sure there is. If there was a Li-Ion pack the same size as the two AAs
    in the A540, then the A540 would get about 500 shots from a battery. The
    reason the manufacturers use AA batteries is because it saves them the
    expense of providing a rechargeable battery and charger. The AA
    batteries are less energy dense for a given weight and volume, and have
    other performance issues that may or may not be important considerations
    for you, but the main reason they are used in the low-end cameras is
    because they're cheap.
     
    SMS, Nov 21, 2006
    #9
  10. void

    ASAAR Guest

    Typical store drones that have no qualms about spouting
    disinformation. They probably have no idea how many shots the A540
    can take and might even be playing games with customers. The next
    one might be told just the opposite. Canon, like many other camera
    manufacturers is conservative about evaluating battery life, using a
    test based on the CIPA standard test procedure, which among other
    things takes each shot after fully zooming the lens, and every other
    shot uses a full power flash. The manual for the A530/A540 states
    that it's good for 90 shots using alkaline batteries or 360 shots
    using NiMH AA batteries, in both cases with the LCD monitor turned
    on. If the LCD monitor is turned off and the viewfinder is used
    instead, alkalines are good for 600 shots and NiMH batteries are
    good for 1000 shots per charge. These last numbers may not be using
    the CIPA procedure, so perhaps the flash wasn't used for them. But
    in any case, if a salesman tries to compare the SD600 using Li-Ion
    batteries, the A540 should be compared using NiMH rechargeable
    batteries, and whether you use the CIPA test results of 360 shots or
    the less stringent test getting 1000 shots, the SD600 with its
    unspecified 200 shots falls far behind. Dpreview hasn't reviewed
    the SD600, but their review of the SD550, which uses an NB-3L Li-Ion
    battery says "Battery life when using LCD not fantastic" and:
    So it's very likely that the SD600 gets about 1/2 the number of
    shots per charge than the A540 gets, under similar conditions. High
    quality name brand NiMH batteries are much cheaper than Li-Ion
    batteries, and you can get good "smart" chargers that can recharge
    the NiMH AA cells in as little as 15 minutes.

    One other thing to consider. Some people have preferred Li-Ion
    batteries because they could hold a charge far longer than
    traditional NiMH batteries before they need to be recharged, due to
    self-discharge losses. Sanyo and RayOVac have a new type of NiMH
    battery that can go 3 or 4 times longer between charges than Li-Ion.
    Sanyo's are called "Eneloop" batteries, and RayOVac's are called
    "Renewal" batteries (not to be confused with their older, dismal
    "Renewal" alkaline batteries). These new NiMH cells can retain much
    of their initial charge even after sitting on a shelf for up to two
    years, and when charging, any standard NiMH charger can be used.
    Unlike most NiMH batteries that require charging before their first
    use, these new NiMH types state on their packaging that they're
    precharged and can be used immediately.

    Your skept-O-meter is working and well calibrated. :)
     
    ASAAR, Nov 21, 2006
    #10
  11. void

    Bill Guest

    Hardly.

    Read your own words again:
    You said the above, but those are opposites.
    It must be one or the other.

    I know that Ni-MH has a "flat" curve in relation to it's overall
    discharge rate, but it has two large drops in voltage at the beginning
    and end of it's curve - a stepped curve, which is also what I said in
    my last post. Your quoted material merely confirms that.
    You don't specify where you got the info, but it is incorrect:

    http://www.hardingenergy.com/faq.htm

    " The Li-Ion voltage will have a linear decreasing voltage from
    4.2-3.0V."

    While the overall curve is very gradual, it's still a linear and
    steady curve. Ni-MH has a lower voltage drop over the charged and
    discharged states - 0.4v per cell. Li-Ion has a 1.2v drop over it's
    discharge curve.

    I had to research and evaluate this stuff for weeks. But again, you
    can interpret and believe whatever you want.
     
    Bill, Nov 21, 2006
    #11
  12. void

    Pete D Guest

    Actually it is the drops that I was refering to and is the first one that
    many cameras do not like.

    From the URLs that you posted.
     
    Pete D, Nov 21, 2006
    #12
  13. void

    void Guest

    Thanks for the responses everyone!
     
    void, Nov 21, 2006
    #13
  14. void

    Bucky Guest

    Who said anything about alkalines? The OP made it sound like he was
    comparing Li-ion to NiMH AAs.
     
    Bucky, Nov 21, 2006
    #14
  15. void

    Bucky Guest

    The salesman did not make any claims that Li-ion had every advantage
    over NiMH, only that it holds a lot more charge.
     
    Bucky, Nov 21, 2006
    #15
  16. void

    Bucky Guest

    I'll throw my 2 cents in here too. First of all, I'll assume that by AA
    you meant AA NiMH, not alkalines. As far as I know, Li-ion has higher
    energy density than NiMH. The Li-ion battery for the SD600 is far
    smaller than 2 AAs. I doubt that the shot discrepancy is that high
    though, it's probably about the same.
     
    Bucky, Nov 21, 2006
    #16
  17. void

    Ron Hunter Guest

    Lithium ion batteries hold more power per weight unit than NIMH, but
    saying that they hold more power is rather misleading. I seriously
    doubt than ANY camera from a reputable manufacturer would only get 30-40
    shots from NIMH batteries. Lithium ion batteries have several
    advantages, such as weight, lack of high self-discharge rate, and great
    temperature range performance. Power to weight ratio is also great, but
    cost and durability are rather negatives.
     
    Ron Hunter, Nov 21, 2006
    #17
  18. void

    Ron Hunter Guest

    I suspect that he was TOLD that, but the clerk's assertion of only 30-40
    shots from NIMH leads to the conclusion he was either confusing NIMH
    with alkalines, or was outright lying.
     
    Ron Hunter, Nov 21, 2006
    #18
  19. void

    Ron Hunter Guest

    A recent browsing of CompUSA turned up a battery/charger set that claims
    to charge their NIMH batteries in 8 minutes! Of course you probably
    can't touch them for an hour......
     
    Ron Hunter, Nov 21, 2006
    #19
  20. void

    ASAAR Guest

    That's nothing. I have some NiMH batteries that take only 4
    minutes to go from flat to a full charge!

    (Unfortunately, that's with my 3 hour charger. If you want to
    know why I didn't dispose of them last year, I'll have to consult
    with my inner packrat.)
     
    ASAAR, Nov 21, 2006
    #20
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