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Solar AA battery chargers thru-hiking

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Solar AA battery chargers thru-hiking

Postby Hetchy » Fri Feb 06, 2009 9:15 pm

Hello my Friends, Mr. Low tech backpacker here.
I am going on a thru hike and have a digital camera that eats AA batteries. I am decidedly low tech on the trail; no MP3 thingy, no ipod(had one but ran it over with the jeep while getting the mail), no GPS(I am a cranky old map and compass guy), no rescue transmitter(I self rescue), and no cell phone(defeats the purpose of the whole activity.. for me)
What I definitely carry is a digital camera.. My mom likes to paint pictures from the photos I take. Absolutely true..( It is quite trippy to go the her house and suddenly see something like Piute Mountain from the exact angle I remember it... only in water color)!
I am feeling guilty about buying 3000 AA's for my 2627 mile thru hike so I am considering some type of solar rechargeable set up. I just need to recharge two AA's about every four days. I have found lots of systems but has anyone actually used these things in the field???
One further note: It MUST be waterPROOF, cause I always manage to do the near drowning thing at every river fording oportunity.
Any and all advice appreciated :)
Thanks ahead of time cause I just know you'all will come through on this one.
PS.
I am so behind the curve that this computer Is an AMD-333 on dial up, and I don't even have a TV ...because, of course I spilled water down the dang thing and got it wet... not kidding.
Like I said needs to be waterproof.. HAHA
Oh yea, I would be cool if it weighed like 0.00001 ounces(now I am kidding myself!)
Cheers & Thanks
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Re: Solar AA battery chargers thru-hiking

Postby BSquared » Sun Feb 08, 2009 3:08 pm

Coincidentally, I just happened to be leafing through my copy of Colin Fletcher and Chip Rawlins's Complete Walker IV, and Chip Rawlins has a whole subchapter in there devoted to the "Solar campsite." It's out of date, of course (2002), but it would be a good place to start: pp. 604-611 or thereabouts. And I *believe* Mr. Rawlins answers his e-mail (unlike most authors -- they do get a ton, so it's understandable) , but I can't vouch for that for sure.

-B2
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Re: Solar AA battery chargers thru-hiking

Postby Hetchy » Sun Feb 08, 2009 6:51 pm

Hey! Thanks for that reply.. I am gonna check it out.
On a side note I have often wondered why electronics makers have not responded to the need for renewable energy for personal electronics by integrating solar power. A simple folding solar panel that plugged into a cell phone or digital camera when set in the sun between uses seems an obvious way to avoid putting tons of heavy metals into the landfills (more convieninet than plugging into a ciggarette outlet in the case of the phone for us contractors in the field). Maybe there is just to much lobbying power behind the battery makers.
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Re: Solar AA battery chargers thru-hiking

Postby rlown » Mon Feb 09, 2009 10:03 am

You might want to look at the foldable Brunton solar panels at http://www.brunton.com/product.php?id=409. I think REI carries them also.

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Re: Solar AA battery chargers thru-hiking

Postby dave54 » Tue Feb 10, 2009 9:34 pm

I have often wondered why electronics makers have not responded to the need for renewable energy for personal electronics by integrating solar power.


They have.

The problem is the solar cell technology just isn't there yet to be practical. You would either have to carry a whole lot of solar cells, or wait all day to charge up enough power to use the device for a few minutes. This is also why the pocket sized solar rechargers are not real popular yet. Mounting it on your pack does not work well, as you are constantly entering and leaving shade, changing sun angle as you move, etc. They don't really work while hiking. You have to devote about a whole layover day with the recharger laying in direct sunlight to recharge just a couple of batteries. If the day is overcast, or you are in the bottom of a deep canyon with only a few hours of direct sunlight, then you will not get a full recharge even after all day.

Just practice extreme power management to make your batteries last. Leave the camera turned off until you are just ready to shoot, use the no-flash settings, and remove the batteries at night to minimize vampire power usage.
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Re: Solar AA battery chargers thru-hiking

Postby Hetchy » Thu Feb 12, 2009 9:41 pm

Thanks Dave54. I have been looking into these devices; such as the roll 'em up solar panel. And the charge rates look impressive until you read the fine print.
The max output rating is under ideal conditions; full sunlight at a perpendicular angle. Add to that the ampere hour capacity for a AA nickel metal hydride can be 2200 mAh or 2.2 Amp hours.. could take the panel a long time to do it's thing at a realistic 160 mAh charge rate under trail conditions.
Too bad.
I guess I might as well bust out that crowbar again and pry open the wallet and get me that costco super "pack'O'cells" and pick 'em up at resupplies.
I kinda took the hint also when nobody immediately hit me back with something like: "Yea, I used one of those things and it worked great!"
Maybe someday Humans will just be born with a danged ole USB port and that would solve all our charging problems! (My god, that would create more problems!) :(
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Re: Solar AA battery chargers thru-hiking

Postby BSquared » Fri Feb 13, 2009 4:46 am

Hetchy wrote: I guess I might as well bust out that crowbar again and pry open the wallet and get me that costco super "pack'O'cells" and pick 'em up at resupplies.

You'll be buying lithiums, right? I swear by those -- one pair in my camera lasted through an entire JMT through-hike and had plenty of charge to spare, they work when it's cold, and they weight about half as much as alkalines. Can't pack 'em in your air luggage, though...

-B2
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Re: Solar AA battery chargers thru-hiking

Postby Hetchy » Fri Feb 13, 2009 8:13 pm

You B right Bsquared. I remember how much lighter those lithiums are compared to alkalines or even nickel metal hydrides.
A side note: I once pryed open a camera type battery (CR5 I think).. anyways it contained two AA size cells but each was 1.7 volts. It made the Old Sierra Zip stove run like Elrond's forge.. I mean I could have forged steel in that thing! I carry the Trangia alcohol stove now so no AA required. Though I am gonna miss my little "portable campfire". I digress..
I will most definitely use those lithium cells for the Pentax Optio. And thanks for the advice all.. I really appreciate it! :)
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Re: Solar AA battery chargers thru-hiking

Postby fishmonger » Sat Mar 07, 2009 9:47 am

High tech backpacker here - we carried High Def camera, GPS, MP3 player, cell phone and headlights last summer. To keep all this powered, I got a Brunton 9w watt SolarRoll charger. It is BIG, puts out lot of power, has a 12V cig ligher outlet so you can plug in anything that would charge a battery in a car.

Result - it sucked. Why did it suck? Even this big panel will ONLY charge batteries if you leave it stationary at a near right-angle to the sun. Great if you make camp from 10am to 3pm every day. However, hiking southbound on the JMT in rather cloudy/rainy weather for half the hike, we couldn't even charge anything in a 1 1/2 day layover at Reds Meadows.

Worst of all - the AA batteries were the hardest to charge. No idea why, but the charger I bought was a pretty fancy one, but the life of these batteries was maybe 3-4 hours in our GPS (compared to 18 hours for a regular Duracell Copper top, or 60 hours for Energizer E2 Lithiums).

We stopped charging the AAs and focused on the 7.4V HD camcorder batteries. Those we kept just charged enough to be able to shoot 5 hours of tape on the hike. Much less than planned. The mp3 player we never plugged in and will leave behind this year, the Cell phone kept its charge all hike, because it was useless between Reds Meadows and the end of the hike.

Looking at the weight of the charger, and the rather bulky load it makes when rolled up, I am not taking it back into the mountains. Everything we have this year will be powered by Energizer E2 Lithiums which weigh 2/3 of normal AAs and give you 5x the life, which boils down to 7.5x the power to weight ratio of normal AAs. That's plenty of power between food depots where they can be replaced. For my HD camcorder, I am building a custom external supply that runs on these replacable batteries. GPS will run on 2AAs for 4 days, headlights run on a single AA for 10 days. The weight saved in solar charger and charging adapters:

Brunton Solar Roll - 305g
12V outlet adapter - 55g
Camera charger - 76g
camera 2nd battery - 90g
AA battery charger w 2 sets of rechargeable AAs - 175g
Cell phone charger adapter - 60g
USB cig lighter charger adapter - 55g
ipod charger cable - 20g

that adds up to almost 2 pounds...

This year I am bringing an AC charger for the ipod if the kids insist on bringing it and charge it at every AC power jack we find along the trail.

For the HD camera, the custom built external Litium pack should weigh less than 200g and run for more than 4 days. Worst case will be the Muir Ranch to Whitney section, where we'd need a second set of batteries or bring my two fully charged regular batteries as well. This is still far lighter than the Solar charger, though, requires no time parked in the sun for hours, and is guaranteed to work.
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Re: Solar AA battery chargers thru-hiking

Postby fishmonger » Sat Mar 07, 2009 9:51 am

Hetchy wrote:You B right Bsquared. I remember how much lighter those lithiums are compared to alkalines or even nickel metal hydrides.


1/3 lighter, 5x the lifetime - the test below was an eye opener for me.

http://www.popphoto.com/popularphotogra ... page2.html
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Re: Solar AA battery chargers thru-hiking

Postby rlown » Sat Mar 07, 2009 12:20 pm

fishmonger wrote:For the HD camera, the custom built external Litium pack should weigh less than 200g and run for more than 4 days. Worst case will be the Muir Ranch to Whitney section, where we'd need a second set of batteries or bring my two fully charged regular batteries as well. This is still far lighter than the Solar charger, though, requires no time parked in the sun for hours, and is guaranteed to work.


I'd actually like to start carrying an HD camcorder. I'd be interested in what you build. In all my research on the Canon line of HD recorders, they never mention a DC recharge option, anyway.

So, how many Li battery packs would i have to take on a 7 day trip for let's say, 15 hrs of recording?

Russ
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Re: Solar AA battery chargers thru-hiking

Postby fishmonger » Sat Mar 07, 2009 4:11 pm

rlown wrote:
I'd actually like to start carrying an HD camcorder. I'd be interested in what you build. In all my research on the Canon line of HD recorders, they never mention a DC recharge option, anyway.

So, how many Li battery packs would i have to take on a 7 day trip for let's say, 15 hrs of recording?

Russ


still am in the testing period. I don't know if I have to add a regulator. My first try is to just put 5 cells in series for about 9V - the DC charger input on the camera (canon HV20, smae as HV30 and probably the new model) is 8.4V, while the batteries are 7.4V.

If that doens't go so well, I will have to add another cell to get high enough above the 8.4V and regulate it down to 8.4V, or I will need to sacrifice a battery to make an adapter to feed 7.4V through the battery contacts.

I'll have more info in a week or two - currently am a few cells short of being able to test with real Lithiums.

There is no aftermarket option for this, as light wight appears to be irrelevant. Most users are generally close to a car and a simple 12V to 110V AC inverter works for them - they just plug the camera charger into the inverter which plugs into the cig ligher and charge the camera.

In terms of running time, I think the Lithiums will deliver about 2 times the life of a large camcorder battery, so one pack should be enough for almost 3 hours of recording. I'd say I'll need a set every 4 days on the trail just to make sure i have enough juice to do the things I had no battery for last year, such as a long shot of a sunset for time lapse use, etc.

what camcorder do you have? you realy want to bring one that uses tape, none of the internal hard drive mess, which compresses the heck out of your footage and does eventually run out of space with no way to unload the data when you're on the trail.
Last edited by fishmonger on Thu Dec 30, 2010 10:24 am, edited 1 time in total.
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