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Solar power supply recommendations wanted

 
 
Paul Rubin
Guest
Posts: n/a
 
      02-07-2007
Ken Lucke <(E-Mail Removed)> writes:
> Because for a [sometimes] 2-3 week interval (you see, I'm _planning_ on
> taking it slow so that I can photograph), I calculate that I will be
> using one set of 2 AAs (for the GPS) every three days or so and one set
> of 6 AAs (for the battery grip on the camera, if I choose to go with
> thhem instead of the NL2B batteries) every three days or so (as I've
> calculated would be about right), plus batteries for the mini-HD
> storage unit, plus flashlight batteries (even LED flashlights DO run
> out of power), etc. Believe it or not, that comes out to "dozens".


OK, I'm still having trouble, why do you need to use the GPS that
much? How will you use it? Is it not enough to just power it up once
in a while to get a location fix?

What about the flashlights? Why use them so much? I'm a flashlight
junkie myself but I don't think I've ever needed a flashlight for more
than a few minutes a night on a camping trip. And LED lights can be
run at very low power for many purposes.

> I'll never know until I get there, will I? This trip is not only for
> pleasure, but is a plannned photo shoot, with the full intent of coming
> back with useable photos. It's not just a casual walkabout.


Hmm, ok, it would help to have some numbers though, so you can
calculate your battery requirements. As you mention, you're going to
make some shorter preparatory hikes, so maybe you could bring charged
batteries for those, and carefully track how often you need t change
them.

> But tell me - have you ever crossed the Mojave desert during full bloom
> of the cactus and wildflowers, as this trip, timed correctly, does?
> Have you ever walked a high mountain snow ridge in the deep High
> Sierras with the incredible vistas that result, right at the very first
> spring accessibility, as this trip, timed correctly, does? Have you
> ever spend days hiking through alpine meadows during wildflower season,
> as this trip, timed correctly, does? How about traversing around high
> mountain lakes with their surrounding peaks mirrored in the still blue
> waters? How about the abandonded mining & ghost towns you trundle
> through, with all their photo opportunities?


Well, my own travel experiences have been that I shoot a lot of photos
on the first few days, then less and less as the trip goes on. The
longest trip I've been on was about 2.5 months and I shot a total of 5
rolls of film (36 exp/roll) and I think I got all the highlights.
Maybe with a digicam I'd have shot 3x as much but I wouldn't have shot
100x as much. One pack of AA cells would still have been plenty. If
you use the optical viewfinder (sounds like you're bringing a DSLR, so
there's no LCD viewfinder anyway) and don't use the LCD playback or
the built-in flash too much, you can really shoot an enormous amount
with today's cameras.

As sort of a weird aside, in my own (mostly-urban) travels I haven't
had to worry much about food or batteries, but a big ongoing hassle
has been finding places to do laundry. Carrying more than a week's
worth of clothes gets pretty cumbersome, so there was this constant
search for laundromats and the like in every new city (and they're not
all that common in some places). Even when staying in someone's home
overnight, in many places it's typical for families to have a washing
machine but no dryer. They just wash stuff and then let it air-dry
for a couple days, which is not so convenient if you're not staying in
the same place for that long. I'd sometimes wash stuff in a washing
machine and then dry it with a clothes iron, one item at a time. I'm
not sure how a PCT hiker would deal with this issue.

> However, that doesn't eliminate my need for power while _not_ in those
> locations, nor reduce the number of batteries I would have to carry for
> some of the intervals, which could be quite numerous. I will probably
> be adjusting my routine, depending on the duration of each leg, so that
> some of the time I might just carry spares, and some of the time I
> might carry the charger system, but that still doesn't eliminate my
> need for the charger system altogether for those longer legs.


I think what you have to figure out is how many total watts of power
you need, and size your solar array from that.

Are you going to have a camping stove? I wonder if there's some fuel
cell solution possible.

> Which is why I'm asking for _real_ _world_, _actual_ _experience_


I'm not aware of anyone ever powering a sizeable lithium ion charger
from solar cells as you're imagining (sizeable = for something larger
than a cell phone battery). All the solar chargers I've seen
basically direct charge NiMH cells at whatever current the cells can
deliver. If there's cloud or tree cover, the amount of current
available is lower, so the cells charge more slowly, but things are
otherwise normal. Lithium ion chargers need fancy electronics to
monitor the cell voltage and adjust the charging current, they expect
to be plugged in the wall where the amount of power they need is
always there, and I'd be concerned they could get confused if for some
reason the expected amount of input power was unavailable or even if
it was just interrupted (like if you sat down under a tree for a few
minutes). So you're probably better off with AA's.

Overall though, the number of cells you're talking about charging are
going to need quite a lot of collection area even under the best of
conditions. Your own conditions are going to depend on your own
hiking locations. I can tell you for sure that where I hike, because
of the amount of tree cover, solar power would be useless and even GPS
doesn't work all that well.
 
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Ken Lucke
Guest
Posts: n/a
 
      02-07-2007
In article <(E-Mail Removed)>, Paul Rubin
<http://(E-Mail Removed)> wrote:

> Ken Lucke <(E-Mail Removed)> writes:
> > Because for a [sometimes] 2-3 week interval (you see, I'm _planning_ on
> > taking it slow so that I can photograph), I calculate that I will be
> > using one set of 2 AAs (for the GPS) every three days or so and one set
> > of 6 AAs (for the battery grip on the camera, if I choose to go with
> > thhem instead of the NL2B batteries) every three days or so (as I've
> > calculated would be about right), plus batteries for the mini-HD
> > storage unit, plus flashlight batteries (even LED flashlights DO run
> > out of power), etc. Believe it or not, that comes out to "dozens".

>
> OK, I'm still having trouble, why do you need to use the GPS that
> much? How will you use it? Is it not enough to just power it up once
> in a while to get a location fix?


I don't need it to /hike/ at all - I've hiked for over almost 40 years
(since Cub Scouts) without needing one. It's to provide the GPS EXIF
data for the photos. Therefore, I have to have it up and running and
locked in (which takes a minute or so at times, dependent on satellite
signals) any time I'm photographing.

>
> What about the flashlights? Why use them so much? I'm a flashlight
> junkie myself but I don't think I've ever needed a flashlight for more
> than a few minutes a night on a camping trip. And LED lights can be
> run at very low power for many purposes.


Well, partially because I do plan on spending more time on photography
than normal, so I plan on hiking earlier in the morning and later into
the evening than normmal (as well as picking up the pace on a
mile-per-hour basis, all of which will still progbably slow me down and
make the overall hike longer than normal), unless I find a spot I want
to overnight at to get an early morning pic. Unfamiliar trails can be
deadly if you are not able to see what you are doing - LED headlamps,
while highly efficient, still consume power.

> > I'll never know until I get there, will I? This trip is not only for
> > pleasure, but is a plannned photo shoot, with the full intent of coming
> > back with useable photos. It's not just a casual walkabout.

>
> Hmm, ok, it would help to have some numbers though, so you can
> calculate your battery requirements. As you mention, you're going to
> make some shorter preparatory hikes, so maybe you could bring charged
> batteries for those, and carefully track how often you need t change
> them.


Yes, that's planned, but I also need to do thhe assessments of the
charging system at the same time.

> > But tell me - have you ever crossed the Mojave desert during full bloom
> > of the cactus and wildflowers, as this trip, timed correctly, does?
> > Have you ever walked a high mountain snow ridge in the deep High
> > Sierras with the incredible vistas that result, right at the very first
> > spring accessibility, as this trip, timed correctly, does? Have you
> > ever spend days hiking through alpine meadows during wildflower season,
> > as this trip, timed correctly, does? How about traversing around high
> > mountain lakes with their surrounding peaks mirrored in the still blue
> > waters? How about the abandonded mining & ghost towns you trundle
> > through, with all their photo opportunities?

>
> Well, my own travel experiences have been that I shoot a lot of photos
> on the first few days, then less and less as the trip goes on.


With the constantly changing conditions, locations, and subjects, I
don't think that will be the case with me - there will be too much
variety to get "bored" with shooting it.

> The
> longest trip I've been on was about 2.5 months and I shot a total of 5
> rolls of film (36 exp/roll) and I think I got all the highlights.
> Maybe with a digicam I'd have shot 3x as much but I wouldn't have shot
> 100x as much. One pack of AA cells would still have been plenty. If
> you use the optical viewfinder (sounds like you're bringing a DSLR, so
> there's no LCD viewfinder anyway) and don't use the LCD playback or
> the built-in flash too much, you can really shoot an enormous amount
> with today's cameras.


As I said, I can go for almost a whole day with one set of batteries
normally - but factor in decreased efficiency in the cold, multiple
days, etc., and it starts adding up.


> As sort of a weird aside, in my own (mostly-urban) travels I haven't
> had to worry much about food or batteries, but a big ongoing hassle
> has been finding places to do laundry. Carrying more than a week's
> worth of clothes gets pretty cumbersome, so there was this constant
> search for laundromats and the like in every new city (and they're not
> all that common in some places). Even when staying in someone's home
> overnight, in many places it's typical for families to have a washing
> machine but no dryer. They just wash stuff and then let it air-dry
> for a couple days, which is not so convenient if you're not staying in
> the same place for that long. I'd sometimes wash stuff in a washing
> machine and then dry it with a clothes iron, one item at a time. I'm
> not sure how a PCT hiker would deal with this issue.


A hole in the ground (or a gap between logs, etc.,), a poncho to line
it, and lots of biodegradable soap. That, and stink a lot. You can
usually tell how long someone you meet on the trail has been there by
how far downwind you can detect them :^)

>
> > However, that doesn't eliminate my need for power while _not_ in those
> > locations, nor reduce the number of batteries I would have to carry for
> > some of the intervals, which could be quite numerous. I will probably
> > be adjusting my routine, depending on the duration of each leg, so that
> > some of the time I might just carry spares, and some of the time I
> > might carry the charger system, but that still doesn't eliminate my
> > need for the charger system altogether for those longer legs.

>
> I think what you have to figure out is how many total watts of power
> you need, and size your solar array from that.
>
> Are you going to have a camping stove? I wonder if there's some fuel
> cell solution possible.


Small MSR Firefly I've used for years. No way to get electrical out of
it :^)

> > Which is why I'm asking for _real_ _world_, _actual_ _experience_

>
> I'm not aware of anyone ever powering a sizeable lithium ion charger
> from solar cells as you're imagining (sizeable = for something larger
> than a cell phone battery). All the solar chargers I've seen
> basically direct charge NiMH cells at whatever current the cells can
> deliver.


There are several available options that provide a 12v
cigarette-lighter type output which, with decent sunlight, are
supposedlyrated for that output. I'm trying to find someone who has
actually used them.

> If there's cloud or tree cover, the amount of current
> available is lower, so the cells charge more slowly, but things are
> otherwise normal.


I'm quite aware of the basic concepts of solar power. I'm looking for
specific usage experience.

> Lithium ion chargers need fancy electronics to
> monitor the cell voltage and adjust the charging current, they expect
> to be plugged in the wall where the amount of power they need is
> always there, and I'd be concerned they could get confused if for some
> reason the expected amount of input power was unavailable or even if
> it was just interrupted (like if you sat down under a tree for a few
> minutes). So you're probably better off with AA's.
>
> Overall though, the number of cells you're talking about charging are
> going to need quite a lot of collection area even under the best of
> conditions. Your own conditions are going to depend on your own
> hiking locations. I can tell you for sure that where I hike, because
> of the amount of tree cover, solar power would be useless and even GPS
> doesn't work all that well.


There will certainly be areas like that, but there are also areas
completely clear of cover (the Mojave, as one example, or some of the
higher mountain passes/ridges above or near the treeline) where
sunlight, unless it's inclement weather, should be plentiful. Plus,
there are planned full- or multi-day stops at certain places, so the
charger can be placed in an optimal location for a whole day or so.

--
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
 
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Paul Rubin
Guest
Posts: n/a
 
      02-07-2007
Ken Lucke <(E-Mail Removed)> writes:
> I don't need it to /hike/ at all - I've hiked for over almost 40 years
> (since Cub Scouts) without needing one. It's to provide the GPS EXIF
> data for the photos. Therefore, I have to have it up and running and
> locked in (which takes a minute or so at times, dependent on satellite
> signals) any time I'm photographing.


Hmm, ok. But there are GPS receivers that are very efficient. I have
a Garmin Geko which runs for 12 hours or so on two AAA's, so something
comparable with AA's should run for 24+ hours or 12 hours per AA, so
running it 6 hours/day that's 0.5AA/day, is that reasonable?

> Well, partially because I do plan on spending more time on
> tphotography han normal, so I plan on hiking earlier in the morning
> tand later into he evening than normmal ... LED headlamps,
> while highly efficient, still consume power.


Well, a 1 watt LED is quite powerful these days, and a NiMH AA cell is
about 3 WH, so 0.5 AA/day lets you run the light for 1.5 hours/day at
1 watt. Backing off to 0.5 watts doubles this and is still a fair
amount of light, especially with the most recent LED's (Cree XR-E or
equivalent). Do you have a particular model of headlamp you're going
to use? It might be worth your while to upgrade its leds, since the
newest ones are around 2x as efficient as older ones but haven't made
it into any production headlamps yet as far as I know.

> As I said, I can go for almost a whole day with one set of batteries
> normally - but factor in decreased efficiency in the cold, multiple
> days, etc., and it starts adding up.


Measurements down to freezing temperatures (0 C) with Sanyo Eneloop
cells indicates not much capacity change. Below freezing there is a
big drop-off and lithium starts becoming worthwhile.

I despise lithium ion batteries in general but maybe this is a rare
situation where you want to think about external lithium packs because
of the weight savings. Sony NP-F970 knockoff packs (7.2 volts, 6000
mAH) are about $30 each on fleabay and they weigh maybe half of what
the comparable NiMH packs would weigh. Of course you'd need wiring
and crap to power your stuff with them, and there's the charging
complexity to deal with.

> Small MSR Firefly I've used for years. No way to get electrical out of
> There are several available options that provide a 12v
> cigarette-lighter type output which, with decent sunlight, are
> supposedly rated for that output. I'm trying to find someone who has
> actually used them.


From what I've heard, they do meet their specs under full sunlight,
the issue is the availability of full sunlight in your application.

> I'm quite aware of the basic concepts of solar power. I'm looking for
> specific usage experience.


As mentioned in another post, having enough power to run a smart
charger is a different issue than just being able to put some variable
amount of power into your batteries.

> There will certainly be areas like that, but there are also areas
> completely clear of cover (the Mojave, as one example, or some of the
> higher mountain passes/ridges above or near the treeline) where
> sunlight, unless it's inclement weather, should be plentiful. Plus,
> there are planned full- or multi-day stops at certain places, so the
> charger can be placed in an optimal location for a whole day or so.


Well, in another power you mentioned using six AA's per day to run
your camera and a microdrive. Let's be a little optimistic and cut
this to 3AA/day based on using flash memory and minimizing chimping.
Then we'd guessed at 0.5 AA/day for each of the GPS and the headlamp,
so 4AA per day. Since charging is not 100% efficient let's say you
need 4WH to charge a 3WH cell. I think you better not depend on solar
flux higher than 25% or so (tree and cloud cover, sun angle) and 8
hr/day of charge time, and even that is probably pushing it. So you
need 4 watts of solar panels to charge 1AA per day, or 16 W of panels
for 4AA/day. That is maybe at the edge of doability: a couple of
square feet of collection surface, somewhat less with the best
monocrystalline cells but those tend to be in very solid, heavy panels
with glass covers etc.

Here is a supposedly 26 watt charger that's about 2'x3' when fully open:

http://www.powerportstore.com/Solar%...g%20-%20AR.htm

(scroll down to the larger unit). You might consider that in the
hopes of using it at stationery locations per your description.
There's also a 6 watt flexible backpack panel there that I think makes
more sense for use while walking, and a 5 watt fold-out unit (I think
non-flexible) that's very lightweight. Remember for the big panel
you'll also need some kind of power conversion and smart charging
system = yet more weight.

But, I wouldn't worry about that situation of running out of battery
power right at the end of the day when an extra special shot comes up.
Just carry a reserve NB-2L pack for those extra special situations.

Overall, I'd plan a strategy based on minimizing total power
consumption, plus use of vehicle or AC chargers and mailed-ahead
batteries, rather than planning to use profligate amounts of power and
shlep around large solar collectors. At worst, 4AA/day is about 2
pounds of batteries per week with no recharges at all, which is far
less than your food intake, so maybe you could cover the whole thing
with a mail-ahead strategy (mail your discharged cells home, where
someone can recharge them and send them back to you at your next
location).

If it were me, I'd use a compact camera and ditch the GPS EXIF
requirement (just mark on a map where the interesting shots are) and
expect to get by with 2AA/week or so, but that's a different approach
than what you've settled on.
 
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Al Dykes
Guest
Posts: n/a
 
      02-07-2007
In article <(E-Mail Removed)>,
Paul Rubin <http://(E-Mail Removed)> wrote:
>Ken Lucke <(E-Mail Removed)> writes:
>> I don't need it to /hike/ at all - I've hiked for over almost 40 years
>> (since Cub Scouts) without needing one. It's to provide the GPS EXIF
>> data for the photos. Therefore, I have to have it up and running and
>> locked in (which takes a minute or so at times, dependent on satellite
>> signals) any time I'm photographing.

>
>Hmm, ok. But there are GPS receivers that are very efficient. I have
>a Garmin Geko which runs for 12 hours or so on two AAA's, so something
>comparable with AA's should run for 24+ hours or 12 hours per AA, so
>running it 6 hours/day that's 0.5AA/day, is that reasonable?
>


Buy yourself a package of these as see how long they last in your
gadgets and how light they are. The have a shelf life of forever so
if you buy too many they will not go bad.

http://www.zbattery.com/l91bp8.html

There is a AAA replacement called Energizeer p/n L92




--
a d y k e s @ p a n i x . c o m
Don't blame me. I voted for Gore. A Proud signature since 2001
 
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Paul Rubin
Guest
Posts: n/a
 
      02-07-2007
http://www.velocityreviews.com/forums/(E-Mail Removed) (Al Dykes) writes:
> Buy yourself a package of these as see how long they last in your
> gadgets and how light they are. The have a shelf life of forever so
> if you buy too many they will not go bad.
>
> http://www.zbattery.com/l91bp8.html [Energizer L91 lithium AA's]


These weigh a bit less than regular AA's or rechageables and have a
somewhat more energy per cell, but overall they are ridiculously
expensive, and environmentally unfriendly compared with rechargeables.
Multi-year shelf life is not an issue for the application being
discussed, since the whole trip is just a few months long.
 
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ASAAR
Guest
Posts: n/a
 
      02-07-2007
On Wed, 07 Feb 2007 12:34:39 -0800, Ken Lucke wrote:

>> 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.

>
> 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.


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.


>> 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?

>
> 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.


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.


> Then of course there's the reduced efficiency of the batteries at the
> lower temperatures that will be encountered in many of the locations.


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.

 
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David Dyer-Bennet
Guest
Posts: n/a
 
      02-07-2007
Paul Rubin wrote:

> Well, my own travel experiences have been that I shoot a lot of photos
> on the first few days, then less and less as the trip goes on. The
> longest trip I've been on was about 2.5 months and I shot a total of 5
> rolls of film (36 exp/roll) and I think I got all the highlights.


Well, I'm really glad that makes you happy.

I rarely shoot fewer than 5 rolls of film a *day* on a trip, myself.
Taking pictures is one of my main hobbies, and it's the primary purpose
for the trip so far as I'm concerned.

The thought of deliberately trying to restrict my photography on a trip
is really abhorrent. Why take the time and money for the trip, if I'm
not going to get to have fun?

So if it works for you, great! But recognize that, for this newsgroup,
you're proposing an extreme fringe position, and not many people are
going to be attracted to it.
 
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Ken Lucke
Guest
Posts: n/a
 
      02-07-2007
In article <(E-Mail Removed)>, Paul Rubin
<http://(E-Mail Removed)> wrote:

> Ken Lucke <(E-Mail Removed)> writes:
> > I don't need it to /hike/ at all - I've hiked for over almost 40 years
> > (since Cub Scouts) without needing one. It's to provide the GPS EXIF
> > data for the photos. Therefore, I have to have it up and running and
> > locked in (which takes a minute or so at times, dependent on satellite
> > signals) any time I'm photographing.

>
> Hmm, ok. But there are GPS receivers that are very efficient. I have
> a Garmin Geko which runs for 12 hours or so on two AAA's, so something
> comparable with AA's should run for 24+ hours or 12 hours per AA, so
> running it 6 hours/day that's 0.5AA/day, is that reasonable?


The 60CSX I have runs for 18 hours on one set of AAs

>
> > Well, partially because I do plan on spending more time on
> > tphotography han normal, so I plan on hiking earlier in the morning
> > tand later into he evening than normmal ... LED headlamps,
> > while highly efficient, still consume power.

>
> Well, a 1 watt LED is quite powerful these days, and a NiMH AA cell is
> about 3 WH, so 0.5 AA/day lets you run the light for 1.5 hours/day at
> 1 watt.


So figure that x 2 (morning and evening) x 3 days.

> Backing off to 0.5 watts doubles this and is still a fair
> amount of light, especially with the most recent LED's (Cree XR-E or
> equivalent).


> Do you have a particular model of headlamp you're going
> to use? It might be worth your while to upgrade its leds, since the
> newest ones are around 2x as efficient as older ones but haven't made
> it into any production headlamps yet as far as I know.


I was planning onpurchasing a new one just before the hike(s), as I am
aware of technology jumps and price drops making making new ones better
for about the same price

>
> > As I said, I can go for almost a whole day with one set of batteries
> > normally - but factor in decreased efficiency in the cold, multiple
> > days, etc., and it starts adding up.

>
> Measurements down to freezing temperatures (0 C) with Sanyo Eneloop
> cells indicates not much capacity change. Below freezing there is a
> big drop-off and lithium starts becoming worthwhile.
>
> I despise lithium ion batteries in general but maybe this is a rare
> situation where you want to think about external lithium packs because
> of the weight savings. Sony NP-F970 knockoff packs (7.2 volts, 6000
> mAH) are about $30 each on fleabay and they weigh maybe half of what
> the comparable NiMH packs would weigh. Of course you'd need wiring
> and crap to power your stuff with them, and there's the charging
> complexity to deal with.


Much more complex than my plan, in fact.

> > Small MSR Firefly I've used for years. No way to get electrical out of
> > There are several available options that provide a 12v
> > cigarette-lighter type output which, with decent sunlight, are
> > supposedly rated for that output. I'm trying to find someone who has
> > actually used them.

>
> From what I've heard, they do meet their specs under full sunlight,
> the issue is the availability of full sunlight in your application.
>
> > I'm quite aware of the basic concepts of solar power. I'm looking for
> > specific usage experience.

>
> As mentioned in another post, having enough power to run a smart
> charger is a different issue than just being able to put some variable
> amount of power into your batteries.
>
> > There will certainly be areas like that, but there are also areas
> > completely clear of cover (the Mojave, as one example, or some of the
> > higher mountain passes/ridges above or near the treeline) where
> > sunlight, unless it's inclement weather, should be plentiful. Plus,
> > there are planned full- or multi-day stops at certain places, so the
> > charger can be placed in an optimal location for a whole day or so.

>
> Well, in another power you mentioned using six AA's per day to run
> your camera and a microdrive. Let's be a little optimistic and cut
> this to 3AA/day based on using flash memory and minimizing chimping.
> Then we'd guessed at 0.5 AA/day for each of the GPS and the headlamp,
> so 4AA per day. Since charging is not 100% efficient let's say you
> need 4WH to charge a 3WH cell. I think you better not depend on solar
> flux higher than 25% or so (tree and cloud cover, sun angle) and 8
> hr/day of charge time, and even that is probably pushing it. So you
> need 4 watts of solar panels to charge 1AA per day, or 16 W of panels
> for 4AA/day. That is maybe at the edge of doability: a couple of
> square feet of collection surface, somewhat less with the best
> monocrystalline cells but those tend to be in very solid, heavy panels
> with glass covers etc.
>
> Here is a supposedly 26 watt charger that's about 2'x3' when fully open:
>
> http://www.powerportstore.com/Solar%...g%20-%20AR.htm
>
> (scroll down to the larger unit). You might consider that in the
> hopes of using it at stationery locations per your description.
> There's also a 6 watt flexible backpack panel there that I think makes
> more sense for use while walking, and a 5 watt fold-out unit (I think
> non-flexible) that's very lightweight. Remember for the big panel
> you'll also need some kind of power conversion and smart charging
> system = yet more weight.
>
> But, I wouldn't worry about that situation of running out of battery
> power right at the end of the day when an extra special shot comes up.
> Just carry a reserve NB-2L pack for those extra special situations.


Uhm, that's why I need the charger - so I _have_ a spare :^)

>
> Overall, I'd plan a strategy based on minimizing total power
> consumption, plus use of vehicle or AC chargers and mailed-ahead
> batteries, rather than planning to use profligate amounts of power and
> shlep around large solar collectors. At worst, 4AA/day is about 2
> pounds of batteries per week with no recharges at all, which is far
> less than your food intake, so maybe you could cover the whole thing
> with a mail-ahead strategy (mail your discharged cells home, where
> someone can recharge them and send them back to you at your next
> location).


"Take care of the ounces, and the pounds will take care of themselves"
:^)

> If it were me, I'd use a compact camera and ditch the GPS EXIF
> requirement (just mark on a map where the interesting shots are) and
> expect to get by with 2AA/week or so, but that's a different approach
> than what you've settled on.


Yes. I didn't spend my money on a decent DSLR and "L" series lenses to
leave them sitting at home and use a P&S.

--
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
 
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Allan Sheppard
Guest
Posts: n/a
 
      02-08-2007
Hi Ken,
Best wishes for your proposed PCT trip.
I have just finished reading "Dancing with Marmots" by George Spearing
who did the complete trip a few years back - well worth a read
(published by lulu.com $25)

Weight and simplicity seem to be the keywords when you are looking at
2800miles and about 120 days on the trail.

You will be replenishing every 8-10 days so I would use AA's for
camera (and GPS) and replace every (say) 2nd visit to the road end.
By using lithiums you will cut down on the weight (but increase the
$). A solar panel would be good but will it (or the connections)
withstand the constant flexing for the trip. In George's book on some
legs he was carrying 2 gals of water (100lb all up) so every ounce
counts.

Cheers,
Allan


On Tue, 06 Feb 2007 14:39:05 -0800, Ken Lucke <(E-Mail Removed)>
wrote:

>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?

 
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Paul Rubin
Guest
Posts: n/a
 
      02-08-2007
Ken Lucke <(E-Mail Removed)> writes:
> The 60CSX I have runs for 18 hours on one set of AAs


If that's two AA's it's comparable to the Geko; if it's four AA's
maybe you want to look for a lower-powered receiver. You might also
be able to use a display-less module since you just want the serial
output.

> > 1 watt LED ... 0.5 AA/day lets you run the light for 1.5 hours/day

> So figure that x 2 (morning and evening) x 3 days.


You mean 3 hours/day, 3 days/week? So 9 hours/week = 3AA/week, even
lower than previous estimate, excellent.

> > Do you have a particular model of headlamp you're going to use?

> I was planning on purchasing a new one just before the hike(s), as I am
> aware of technology jumps and price drops making making new ones better
> for about the same price


Well it's partly a matter of determining how much illumination you
need. What are you using now, and is it bright enough for your
purposes?

> > Just carry a reserve NB-2L pack for those extra special situations.

> Uhm, that's why I need the charger - so I _have_ a spare :^)


You mean the solar charger? I mean bring a fully charged NB-2L and
maybe the lightweight AC charger for it, and just use it as a fallback
when really needed.

> Yes. I didn't spend my money on a decent DSLR and "L" series lenses to
> leave them sitting at home and use a P&S.


Well, good luck, I can't help thinking you may be trying to do too
many things at once. Someone on a pure photography mission would
bring the DSLR and L lenses, but they'd bring them in a vehicle and
not attempt to backpack all the stuff over such a long period.
Someone on a pure hiking mission would just bring a compact camera.
Trying to carry the gear of the pure photographer while having to lug
everything around like a pure hiker sounds masochistic. More than
asking about people's experience with solar rechargers I'd be asking
hikers if any of them ever carried that much camera gear for that long
a period and thought it was worth it.

I was in a similar situation once; my first long vacation after I
finished college, and I was going to bring two film SLR's and 4 lenses
and 40 or so rolls of film. A friend of mine persuaded me to leave
the SLR stuff at home and just bring a zoom P/S camera of the era.
I'm very grateful to him for that, and that was travelling mostly by
bus and train. If I'd had to carry everything 100's of miles on my
back, the SLR's would have been horrendous.

Anyway at least you can ship the DSLR stuff back home if you get tired
of carrying it. Either way I hope you'll post a trip report with
pictures--it will be interesting to see how this turns out.
 
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