Will external battery pack work with a Canon A300?

Discussion in 'Canon' started by Peabody, Sep 10, 2006.

  1. Peabody

    Peabody Guest

    I need to get an inexpensive digital camera that will take pretty
    good pictures for email and other internet transmission. I don't
    anticipate ever wanting to print out a picture.

    If my notes are right, Wal-Mart sells the old Canon A300 for $78.
    That's a 3.2 MP camera with no optical zoom, but the reviews I've
    read seem pretty good.

    The one drawback is the battery situation. It uses 2 AA's, either
    alkaline or NiMH rechargeable. But what I've used in the past with
    a previous camera is an external battery pack, which consists of a
    Radio Shack battery holder which holds two D cells, and the correct
    size power plug soldered to the wires coming off the holder. The
    plug would go into the camera socket where the AC adapter normally
    plugs in. This works pretty well because you get a pretty long run
    off of two D cells without having to replace or recharge, at the
    expense of carrying around the battery pack of course. The D's
    don't cost all that much more than AA's, but last many times longer.

    Anyway, the Canon ACK800 AC adapter which is standard for this
    camera has an output rating of 3.2 VDC, whereas two alkaline D's
    would nominally provide 3.0 VDC.

    Does anyone know whether this voltage difference would cause any
    problems? A problem in this context would mean that the batteries
    are new or nearly new, but the camera thinks they are partly or
    fully discharged because of the 0.2 VDC difference.

    I assume the 0.2 VDC difference is the forward voltage drop across a
    couple of diodes in there somewhere.

    Any predictions?
     
    Peabody, Sep 10, 2006
    #1
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  2. Peabody

    ASAAR Guest

    The A300 is normally powered by a pair of AA batteries. If
    alkalines are used, the initial voltage is about 3 volts. If NiMH
    batteries are used, the initial voltage is about 2.5 volts. By the
    time the voltage has dropped to the point where the camera will no
    longer function, the voltage is probably about 2.1 volts. I think
    that you're worrying unduly about whether a pair of D cells would
    work. But if you use a pair of internal high capacity AA NiMH
    cells, I'd be surprised if your external D cell battery pack would
    provide significantly more life. I'd guess about twice the life of
    the NiMH AA cells, if that. NiMH AA cells normally last about twice
    as long as AA alkalines in modern cameras. But in older, power
    hungry cameras, they can last more than 5 times longer. And don't
    think that you'll be able to do better by using NiMH D cells. Most
    of the ones available to consumers (such as from Energizer) are only
    rated at 2,500 mah, which is about the same as garden variety NiMH
    AA cells.
     
    ASAAR, Sep 10, 2006
    #2
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  3. Peabody

    Peabody Guest

    ASAAR says...
    Probably so. What concerned me was the possibility that to
    avoid conflict between the internal batteries (rechargeable
    or not) and the A/C adaptor, there might be a diode
    isolation network that would have the effect of
    significantly dropping the net usable voltage through the
    external jack. Of course a simple switch, actuated by
    plugging in the adaptor, is what you hope they used, but
    I've seen the diode setup used in other consumer electronic
    devices, and the 3.2 VDC output of the adaptor just made me
    suspicious. But if fully charged NiMH's are only 2.5V, then
    I would agree that there is probably plenty of room.
    I have no experience with NiMH batteries, only NiCads. With
    my old camera, I found that the external battery pack, which
    actually only used alkaline C cells, lasted much much longer
    than internal NiCad AA's. And the pack for the A300 would be D
    cells, not C's.

    The other thing is that I will use the camera only a few
    times a year. And my experience is that rechargeables will
    self discharge over a month's time so that you always have
    to recharge them before using the camera, and if left too
    long, they sometimes won't come back. Alkalines, on the
    other hand, have a very long shelf life, so you are pretty
    much always ready to go.

    So I thought that I would avoid the investment in the NiMH
    batteries, and the charger, and just put two alkaline AA's
    in the camera for those times when I just need to take one
    or two pictures, and then have the external pack for when I
    need to be out all day without access to power or new
    batteries.

    That really worked well for me with the old camera. Do you
    know where I could find a mAH comparison between the various
    battery types and sizes? In this case, I would like to
    compare alkaline D's with NiMH AA's to see what the
    difference would actually be.

    Thanks very much for your response, and for Phil's and
    Stewy's.
     
    Peabody, Sep 11, 2006
    #3
  4. Peabody

    ASAAR Guest

    NiCad batteries have always had particularly low capacities. When
    I first used them they were about 400 to 450mah. For many years
    after that they provided 600mah, and those may be the ones you
    replaced with alkaline a C cell battery pack. Alkaline C cells have
    a rated capacity of about 5,000mah, but that varies with current,
    and at the high currents drawn by old cameras, their capacity might
    drop to somewhere between 3,000 and 4,000 mah. Even today you can
    walk into a Circuit City or Staples and examine cordless phone
    battery packs as I did a few days ago. From the shapes, you can see
    that many use AA size cells internally. Some use NiMH cells and
    others use NiCad. All of the NiCad pack I saw were rated at 600mah.
    When you compare that with current NiMH cells which range from 2,500
    to 2,800 mah, there's no comparison. NiMH AA cells will last far
    longer than any NiCad AA cells when used in cameras.


    Good thinking. But if your shots will be outdoors, where you
    won't need to use the flash, you might not even need to use NiMH
    batteries or an external pack. My nearly 2 year old camera uses 4
    AA alkaline batteries, and if the flash is used a lot, can take
    about 200 shots. If the flash isn't used the number of shots can
    exceed 800. Freshly charged NiMH batteries do even better. Newer
    cameras, especially some Canon models, can take an even greater
    number of shots from a single set of AA batteries. The A300
    wouldn't do as well since it uses only 2 AA cells, and is a slightly
    older camera, but whatever camera you get, you should try it out
    first with just some AA alkalines to see if there would even be a
    need for an external battery pack. Using NiMH AA batteries, some
    Canon models (A610, A620 and others) can take up to 1,700 shots on a
    single charge. With a camera like this, even NiMH batteries might
    be overkill, since alkalines would be good for nearly 1,000 shots,
    and as you noted, wouldn't run down after sitting for a month.

    Go to www.energizer.com and click on the Technical Info tab.
    You'll be able to see or download data sheets and application
    manuals for all of their battery types. It won't tell you
    everything you'll need to know, since most cameras are able to fully
    utilize *all* of the energy contained in NiCad and NiMH batteries,
    but only 1/2 (or less) of the energy contained in alkaline
    batteries. Energizer currently shows that their alkaline AA, C and
    D cells are rated at 2,850, 8,350 and 20,500 mah, respectively.
    You'll have to look at the individual data sheets to really
    understand what they are capable of delivering, though. That
    20,500mah figure for D cells is quite misleading, since it is based
    on a load of only 25ma. At currents more typically used by cameras
    (250ma and 500ma), the D cell capacity is rated at only about 13,500
    and 10,500ma, respectively, and this assumes that the cells will
    continue delivering energy down to 0.8 volts per cell. Cameras
    would have shut down long before that point was reached.

    You're welcome.
     
    ASAAR, Sep 11, 2006
    #4
  5. Peabody

    Peabody Guest

    ASAAR says...
    Well, as it turns out, my notes from the other day were
    wrong, and the A300 which I thought was the Canon turned out
    to be a Polaroid. :-( I don't think I want a Polaroid.

    However, after doing more research online, it looks like the
    Canon entry level cameras are pretty good, particularly with
    respect to non-flash picture quality, even at 3.2 MP. The
    A300, however, appears to be particularly bad on battery
    life, whereas the A410 seems to be better in that regard,
    plus having a little optical zoom capability. I was hoping
    to stay under $100 for everything (camera, batteries,
    charger, memory card if needed), but that doesn't look
    likely for the A410, even used on Ebay.

    I really don't need a large frame size - maybe a max of
    1024x768, but more usually 640x480 - but I need it to
    produce really good pics for that size. My old camera takes
    640x480 just fine, but then insists on compressing the hell
    out of them so the file size is about 40k or less, and that
    just screws things up bad. So what appealed to me about the
    Canons is what you can control the amount of compression.
    It won't go totally uncompressed, as I would prefer, but at
    least you can go up to about 250k in file size for 640x480.
    Maybe other brands do that too. As should be obvious by
    now, I really don't have a clue as to what's available at
    the low end these days. Is there a 3 MP camera that is
    generally considered to be the "best deal" for entry level,
    even if no longer manufactured? That's what Ebay is for.
    :)
    Thanks very much. I see what you mean. So the combination
    of high energy storage for their size, plus the flat voltage
    curve until they die abruptly, is what makes the NiMH so
    good. Well, still, as you said before, it would be cheap
    enough to just try the alkalines first to see how they do.

    But from what I read, it's not the flash, but the LCD screen
    that really uses the power. No?
     
    Peabody, Sep 12, 2006
    #5
  6. Peabody

    ASAAR Guest

    At this point, with some P&S cameras getting up to 9mp and 10mp,
    most 3mp cameras are probably going to be the really, really low end
    versions. There may be a few decent 3mp cameras to be had, but I
    wouldn't rule out cameras up to 5mp. You'd probably get the most
    flexibility in getting the best possible 640x480 images by taking
    full resolution pictures (using all 3, 4 or 5mp) and using your
    computer to reduce the resolution and get whatever compression you
    prefer. Even my last, totally underpowered computer (180 or 200mhz)
    took hardly any time to process many images. And this way you can
    produce any size pictures. Sometimes smaller than 640x480 may be
    appropriate for some email pictures. Or a slightly larger size such
    as 800x600 or 1024x768 might be better if you're sending someone a
    picture to be used for background pictures (wallpaper) on their
    computer's monitor.

    No, unless the screen is very large, bright and power hungry. My
    Fuji can take about 200 pictures from a set of alkaline batteries
    when 1/2 of the shots use the flash and the LCD display is used. If
    the flash is not used at all but the LCD display is still used, the
    number of shots that can be taken goes up to about 800 shots. Canon
    cameras can get even better battery life because many of them have
    optical viewfinders, so they aren't forced to use either the LCD
    display or an EVF (electronic viewfinder). To get an idea how much
    power their LCD display use, Canon provides LCD playback time
    information in their manuals. The A610/A620 (4AA) is rated at up to
    16 hours and 40 minutes, whether alkalines or NiMH is used. This
    confirms what I mentioned earlier, that NiMH can last much longer
    than alkaline, but only at very high power loads. When the current
    is very low, alkalines do much better. Canon's cameras that use
    only 2 AA batteries show the effect of having to provide higher
    currents. The A530/A540 can power the LCD display for 5 hours using
    alkaline batteries, and up to 7 hours using NiMH batteries. The
    previous versions of these, the A510/A520 don't do nearly as well,
    getting 3 hours from alkalines and 5 hours from NiMH batteries.
    BTW, the A610 and A620 have also been replaced, by (IIRC) the A630
    and A640. It will be interesting to see if they get more LCD
    playback time than the A610/A620.
     
    ASAAR, Sep 12, 2006
    #6
  7. Peabody

    ASAAR Guest

    If all of Canon's applicable test conditions can be assumed were
    used for its ratings for "LCD Monitor Off", it took more than 10
    hours to take the 1,200 shots using alkalines, and more than 12 1/2
    hours to take the 1,500 shots using NiMH. So I'd guess that the
    CCD, AF and DSP processing chain uses more power than the LCD
    display alone, and when all of them are used, the batteries might
    last for about 6 hours even if no shots are taken.

    Canon doesn't distinguish between different types of playback. It
    would be interesting to know if playback time is noticeably less for
    video playback. I suppose it would have to be at least slightly
    less due to recorded audio.
     
    ASAAR, Sep 12, 2006
    #7
  8. Peabody

    Peabody Guest

    ASAAR says...
    For the old A300, here's what the manual says:

    [#shotsLCD / #shotsNOLCD / replaytime]

    alkaline: 75 / 210 / 90min

    NiMH NB-1AH 200 / 450 / 120min

    Test Conditions:

    Shooting: "Alternating the shots every 20 seconds, with
    flash used every 4th shot, power turned Off and On again
    after every 8 shots."

    Replay: "Continuous replay at 3 seconds per image."

    I guess this would be a lot better for a newer camera.
    But it does like the viewfinder mode is what really eats
    the power up. Actually taking pictures - not so much.
     
    Peabody, Sep 12, 2006
    #8
  9. Peabody

    ASAAR Guest

    Those figures are a little misleading, because the test conditions
    were different. Canon is now using the standard CIPA test
    procedures which are quite a bit tougher on batteries. Most
    significantly, the flash must be full power and must be used every
    second shot, not every 4th shot. That might have brought the number
    of shots using the LCD and flash down from 75/200 to 35/110. The
    A300's LCD may use much more power than newer cameras, but the
    camera also uses much more power when taking pictures. Canon's
    A530/A540 which also uses 2 AA cells gets 90 & 600 shots (CIPA vs
    LCD Off) using alkalines and 360 & 1000 shots (CIPA vs LCD Off)
    using NiMH cells. Everything about the older cameras use much more
    power, it appears. Can you imagine how many shots the A300 would
    get from a fresh set of alkalines if the flash was used for every
    shot? Probably not very much more than a dozen.
     
    ASAAR, Sep 12, 2006
    #9
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