Will external battery pack work with a Canon A300?

On Sat, 09 Sep 2006 20:58:59 -0500, Peabody wrote:

> 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?

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.
 >> Stay informed about: Will external battery pack work with a Canon A300? 

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On Mon, 11 Sep 2006 11:25:00 -0500, Peabody wrote:

>> 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.
>
> 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.

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.



> 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.

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.


> 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.

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.


> Thanks very much for your response, and for Phil's and
> Stewy's.

You're welcome.
 >> Stay informed about: Will external battery pack work with a Canon A300? 

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On Mon, 11 Sep 2006 18:28:34 -0500, Peabody wrote:

> 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.
>

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.


> 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?

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.
 >> Stay informed about: Will external battery pack work with a Canon A300? 

ASAAR <caught.RemoveThis@22.com> writes:
> > But from what I read, it's not the flash, but the LCD screen
> > that really uses the power. No?
>
> No, unless the screen is very large, bright and power hungry.

With the Canon A530, the screen itself doesn't use much power (you can
use LCD playback from stored pictures for a long time), but LCD
preview (i.e. using the LCD as a viewfinder) burns a lot of power. My
guess is that this is because the CCD, AF, and the DSP image
processing chain all have to be active while you're using preview, in
addition to the screen. Playback only uses the screen, plus jpeg
decompression when you scroll between pics or zoom on them.
 >> Stay informed about: Will external battery pack work with a Canon A300? 

On 11 Sep 2006 19:33:16 -0700, Paul Rubin
<http://phr.cx@NOSPAM.invalid> wrote:

>> No, unless the screen is very large, bright and power hungry.
>
> With the Canon A530, the screen itself doesn't use much power (you can
> use LCD playback from stored pictures for a long time), but LCD
> preview (i.e. using the LCD as a viewfinder) burns a lot of power. My
> guess is that this is because the CCD, AF, and the DSP image
> processing chain all have to be active while you're using preview, in
> addition to the screen. Playback only uses the screen, plus jpeg
> decompression when you scroll between pics or zoom on them.

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.
 >> Stay informed about: Will external battery pack work with a Canon A300? 

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 >> Stay informed about: Will external battery pack work with a Canon A300? 

On Tue, 12 Sep 2006 07:56:42 -0500, Peabody wrote:

>> 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.
>
> 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.

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.
 >> Stay informed about: Will external battery pack work with a Canon A300?