Solar power supply recommendations wanted

Discussion in 'Digital SLR' started by Ken Lucke, Feb 6, 2007.

  1. Ken Lucke

    Ken Lucke Guest

    I'm going to be going on some extended backpacking trips this summer,
    trying to get in better shape, in practice, and ready to do the Pacific
    Crest Trail next year.

    I'm looking for recommendations for a solar charging setup for my
    camera & GPS batteries, etc. Because they use different batteries, I'm
    looking at probably having to get a generic 12v solar supply and using
    the 12v chargers for each (yeah, I know... weight, weight, weight -
    ugh).

    My other alternative is to go with all AA batteries and use the holder
    that goes in my camera's battery grip that holds 6 AAs instead of 2
    proprietary Canon (NB2L) batteries, then buy a solar AA battry charger.
    However, the difference of weight of 12 NiMh AAs (two sets) and one
    charger over 4 NB2L (2 sets) and 2 different chargers might be pretty
    minimal, plus the ability to be charging both AAs for the GPS and other
    things and NB2L camera batteries at the same time might offset the
    difference in the long run as well.

    Can anyone give any real-world actual usage recommendations for such a
    system in similar conditions (they'd have to be strapped on the
    backpack(s) externally to charge during the hiking day), and pointers
    to the products that are recommended?

    --
    You need only reflect that one of the best ways to get yourself a
    reputation as a dangerous citizen these days is to go about repeating
    the very phrases which our founding fathers used in the struggle for
    independence.
    -- Charles A. Beard
     
    Ken Lucke, Feb 6, 2007
    #1
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  2. Ken Lucke

    Matt Ion Guest

    I don't know where you're located, but here north of the 49th, Canadian Tire
    caries a number of solar-charging kits, including one that rolls up for storage
    and can roll out across a backpack to charge while hiking.

    Try starting here:
    http://canadiantire.ca/browse/subca...T<>prd_id=845524443281438&bmUID=1170802732723

    and specifically:
    http://canadiantire.ca/browse/produ...older_id=1408474396672503&bmUID=1170802764282
     
    Matt Ion, Feb 6, 2007
    #2
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  3. Look carefully at the power output rating of your panels. Look at the
    assumptions behind those ratings -- latitude and season mostly.
    Consider how many hours you'll be able to expose the panels to sun each
    day (at the very least, you lose optimum angle mounting a panel on top
    of your pack, and often you walk in the shade).

    Compare to the power requirements of charging the batteries you need.
    Last time *I* conducted this exercise, it became clear this wasn't a
    viable approach to powering cameras on a hike for me.

    I don't know if this is still true, or true for your hike plans, and I'm
    not an experienced hiker and not a solar panel expert, so *really*
    don't take any of this as information. Take it as a strong suggestion
    to really work through the math, though, to make sure you know what
    you're getting.
     
    David Dyer-Bennet, Feb 7, 2007
    #3
  4. Ken Lucke

    Matt Ion Guest

    This is true - it's probably also a good time to think about power-saving
    strategies for ALL your gear. Use optical viewfinder(s) whenever possible, turn
    off LCD previews or set them for bare-minimum time, shorten the cameras'
    auto-off times, avoid on-camera flash at all costs, for starters....
     
    Matt Ion, Feb 7, 2007
    #4
  5. Ken Lucke

    Ken Lucke Guest

    All good suggestions (both from you and David) that I was already going
    to include in the daily routine.

    I know I can go a typical 18 hour full-on day with the GPS, and that I
    won't need it /on/ most of the time (I'm actually quite adept at
    map-reading, orienteering, and course plotting), it's just for backup
    and to plot special points I find along the way for later return (say,
    a spot I think will look good in fall colors, etc). So I'mk thinking
    that I probably have 2-3 days use out of a set of batteries there.

    The camera will normally last me a whole day shooting on one [double]
    set of batteries, even when I leave it on, and let it shut itself down
    [which is probably a bad habit for me, but I'm so used to doing it that
    way that it's hard to change just being used to pressing the shutter
    button and being ready to fire], so with power consumption economy
    measures, plus the less frequent use it will get than when I am
    actually out at a pre-planned shoot, it will also probably go for 2-3
    days between battery changes.

    I was already thinking that it will be a two-day charge cycle for the
    batteries under most circumstances, considering light/shade issues,
    time, etc. I'm just looking for someone who's actually using some sort
    of system at this point to know what does and does not work.

    Thanks for the confirmatory input, though - and I'm still looking for
    someone actually doing this.... anyone?

    --
    You need only reflect that one of the best ways to get yourself a
    reputation as a dangerous citizen these days is to go about repeating
    the very phrases which our founding fathers used in the struggle for
    independence.
    -- Charles A. Beard
     
    Ken Lucke, Feb 7, 2007
    #5
  6. Ken Lucke

    Paul Furman Guest

    Can you give us a Canadian postal code? The web site doesn't let me in
    without that.
     
    Paul Furman, Feb 7, 2007
    #6
  7. Ken Lucke

    Ken Lucke Guest

    Use the one it gives as an example if you put in an incorrect one: "M4P
    1V8" :^)

    --
    You need only reflect that one of the best ways to get yourself a
    reputation as a dangerous citizen these days is to go about repeating
    the very phrases which our founding fathers used in the struggle for
    independence.
    -- Charles A. Beard
     
    Ken Lucke, Feb 7, 2007
    #7
  8. Ken Lucke

    ASAAR Guest

    The charger may not be particularly heavy, but the solar panels
    that would be needed to supply sufficient current might be. You
    can't rely on peak output unless the panels are stationary in a
    location that's pretty much guaranteed to have bright sunlight most
    of the time. A solar panel mounted on a moving, swaying backpack
    that can't be precisely aimed at the sun will produce a much lower
    average current. Also, you need to estimate the number of AA cells
    that will be charged each day, and based on the number that will be
    charged simultaneously, you can easily figure out the current that
    the charger will require. This may be much higher than even fairly
    large solar panels can provide. You probably will also want to use
    an old style "dumb" charger, since the varying voltage/current
    supplied by a solar panel may cause a "smart" charger to frequently
    restart. Smart chargers usually charge quickly, and can require
    *many* amps to operate, so a "dumb" charger that charges at not much
    more than a trickle charge rate may be a good match for large solar
    panels. C.Crane (ccrane.com) sells a small solar powered battery
    charger that's probably much too limited to be useful, but they also
    sell a fairly large solar panel that could probably charge all of
    your AA batteries in less than a day, if you could keep it supplied
    with enough sunlight. But that may not be easy to do.

    I don't know how efficient your camera is, but some DSLRs can take
    thousands of shots per charge. Using a battery grip that holds two
    battery packs would naturally allow twice the number of shots. Do
    you know how many shots you'd be able to take using 6 AA cells, for
    both alkaline and NiMH? I assume that most or all of the shots
    won't use flash, so you may be able to take many thousands of shots
    before needing to swap batteries. If so, how many days of shooting
    do you think this would be good for? One day? Two days? A week?
    If close to a week, the number of batteries you'd need for a couple
    of months of shooting may not weigh much more than a charger, a
    solar panel and a couple sets of rechargeable batteries. It may
    even weigh less.
     
    ASAAR, Feb 7, 2007
    #8
  9. Ken Lucke

    Paul Furman Guest

    Paul Furman, Feb 7, 2007
    #9
  10. Ken Lucke

    AustinMN Guest

    This brings to mind another way to save a bit of energy (if you don't
    mind the inconvenience) shorten the shutoff timer. You can probably
    adjust it to something like 30 seconds, one minute, five minutes,
    etc. Setting it to the shortest time that doesn't drive you crazy
    (i.e. not have to constantly turning it back on while shooting) could
    save a bit more battery power.

    Austin
     
    AustinMN, Feb 7, 2007
    #10
  11. Ken Lucke

    Ken Lucke Guest

    Hmmm... that's an aspect I hadn't given any thought to. I'll have to
    check more closely into on how a smart charger operates, whether it's
    based on feedback from the battery or other criteria. My smart
    chargers at home all sense whether a battery /needs/ charging as soon
    as they power up.
    I can get about 600-650 shots using zoom lenses and a 6 GB microdrive
    card, with normal usage of the display., i.e., it's on until you bring
    the camera up to your face, then it shuts off automatically, and of
    course does so when the camera shuts off (the 400D display uses a fair
    amount of power, but it can be turned off).

    For the trip, I'll be using standard CF instead of microdrive, just to
    reduce power consumption, and probably using the display turned off
    most of the time, even while shooting (gosh, I wouldn't want to be
    accused of "chimping", now, would I??? <g>). I'll also break myself of
    the habit of letting the camera shut itself off automatically instead
    of switching it off manually.
    It's actually less than the using the two NL2B batteries - by about
    20%, using alkalines. About 15% less using NiMH rechargeables. All
    the mAh data on the batteries would argue otherwise, but that's actual
    testing.

    I've never tried it with lithium non-rechargeables.

    Then of course there's the reduced efficiency of the batteries at the
    lower temperatures that will be encountered in many of the locations.
    I'm "guesstimating" about 2-3 days. This is based upon my normal daily
    usage (I can normally get by one day with about 600 shots on one
    battery change) when out and about spending an entire day shooting, and
    then reducing for the fact thaht I won't be spending as much time
    dedicated to actually shooting, plus factoring in the other power
    consuption adjustments (plus and minus) I outlined above.

    I'd also much rather err on the side of caution and have too much than
    to lose a perfect shot at the end of a day.

    I do have to actually move right along - I'll have to hike a little
    faster because I'll be stopping to photograph, or stay over a night
    somewhere to catch a sunrise/sunset, etc. There's a progression based
    upon the seasonal flow that you kind of have to keep up with to hit
    everything just right.
    Probably nowhere near that.
    --
    You need only reflect that one of the best ways to get yourself a
    reputation as a dangerous citizen these days is to go about repeating
    the very phrases which our founding fathers used in the struggle for
    independence.
    -- Charles A. Beard
     
    Ken Lucke, Feb 7, 2007
    #11
  12. Ken Lucke

    Ken Lucke Guest

    Yup, that's already included in my routine that I intend to adopt, as
    is shutting the display off (the 400D allows you to shut the display
    off totally) except when I am actually using it, even while the camera
    is "on".

    --
    You need only reflect that one of the best ways to get yourself a
    reputation as a dangerous citizen these days is to go about repeating
    the very phrases which our founding fathers used in the struggle for
    independence.
    -- Charles A. Beard
     
    Ken Lucke, Feb 7, 2007
    #12
  13. Ken Lucke

    ASAAR Guest

    There probably wouldn't be any problem with having the charger
    restart most of the time. But as the cells approach full charge,
    from what I've read, it's more difficult for the charger to sense
    the changing voltage pattern that indicates that it's time to stop
    charging. This would cause the cells to overcharge and probably
    lose at least some, perhaps a lot of their capacity. And they'll
    get hotter when overcharged, maybe hot enough to trip the
    thermistors used to detect excessive heat, but by then the cells
    almost certainly will have suffered some capacity loss.

    Whenever you see that the difference between alkalines and NiMH
    batteries is this slight (as opposed to a 300% or 400% difference)
    you know that the batteries aren't being heavily loaded, and then
    lithium AA cells, which normally last much longer than alkalines,
    also won't provide significantly longer life.

    That's where you can see an exception to what I just said about
    lithium AA cell vs. alkalines or NiMH. They remain efficient at
    temperatures *far* lower than most other battery types, even Li-Ion
    batteries. As an example, I just checked the manuals for some
    cameras (Canon, Olympus, Nikon) and they all share the same
    operating temperature range [ 0 – 40 °C (32 – 104 °F) ] for their
    Li-Ion battery packs. They can operate at temperatures lower than
    this, but they'll lose efficiency, and will pretty quickly reach the
    –20°C to 60°C (–4°F to 140°F) range normally given for safely
    storing Li-Ion batteries. Lithium AA batteries on the other hand
    have an extremely wide –40°C to 60°C (–40°F to 140°F) operating
    range. You can see this printed on Energizer's lithium AA packages
    if you don't want to download the data sheets. I'm sure that 40
    below zero is a much lower temperature than you'll probably ever be
    exposed to, at least for long periods while trying to take pictures.
    I was out late last night and the temperature was below +10°F, and
    that's much too cold for me, even if it wouldn't be for my Fuji or
    Canon cameras, loaded with the 4 AA lithium cells I keep on hand for
    emergencies. :)
     
    ASAAR, Feb 7, 2007
    #13
  14. Ken Lucke

    MrB Guest

    Will you be hiking the full length of the PCT? Hats off to you!
     
    MrB, Feb 8, 2007
    #14
  15. Ken Lucke

    Ken Lucke Guest

    That's the plan, at this point, anyway. If I get too far behind the
    "curve" of distance vs. seasonal change (due to my photography), I may
    have to break it into two sections over two years, but my current plan
    is for 135 days. Definitely a once-in-a-lifetime trip.
    <snip>

    --
    You need only reflect that one of the best ways to get yourself a
    reputation as a dangerous citizen these days is to go about repeating
    the very phrases which our founding fathers used in the struggle for
    independence.
    -- Charles A. Beard
     
    Ken Lucke, Feb 8, 2007
    #15
  16. Ken Lucke

    Ken Lucke Guest

    ^^^^^^^^

    Oops, sorry, typo. That should be 165 days. I'm optimistic, but not
    maniacal :^)

    --
    You need only reflect that one of the best ways to get yourself a
    reputation as a dangerous citizen these days is to go about repeating
    the very phrases which our founding fathers used in the struggle for
    independence.
    -- Charles A. Beard
     
    Ken Lucke, Feb 8, 2007
    #16
  17. Ken Lucke

    eawckyegcy Guest

    Yes. Unless one is willing to carry a very large panel, solar is a
    non-starter for anything except dribble amounts of power or that "I'm
    doing something" feeling (when in fact you aren't). A 30W+ UNI-PAC
    panel is probably the minimum worth considering:

    http://www.unlimited-power.co.uk/Uni-solar_Portable_Solar_Electric_Panels.html

    Compact and robust, though still energy deficient, unless one's hike
    is in a desert.
     
    eawckyegcy, Feb 8, 2007
    #17
  18. Ken Lucke

    eawckyegcy Guest

    A DSLR just sitting there doing nothing with the power switch "on"
    consumes ... well, I couldn't measure the current drawn by a Canon 10D
    in this state. Microamps?
     
    eawckyegcy, Feb 8, 2007
    #18
  19. Ken Lucke

    eawckyegcy Guest

    Eh?

    http://en.wikipedia.org/wiki/Canadian_postal_code

    K1A 0A6

    More are available at google in the obvious manner: pick a business
    at random and ask for its address.
     
    eawckyegcy, Feb 8, 2007
    #19
  20. Ken Lucke

    Matt Ion Guest

    Matt Ion, Feb 8, 2007
    #20
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