[ben_leg]

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I have a K7, and i’m going on a long expedition where i won’t have access to electricity 3 to 4 weeks. Also, there will be section of the trip where it will be very cold... with an altitude that could go get as high as 6000 meters.
I’m pretty sure that my 2 batteries will not be enough... and that I should think of a simple way of getting more energy during the trip.
So i was thinking about buying a battery grip that could accept AA battery and bring with a small AA solar charger...

Any better solutions???

Thanks for your help
Ben
Note: weight is also a concern for that trip.

[hcc]

I have a K7, and i’m going on a long expedition where i won’t have access to electricity 3 to 4 weeks. Also, there will be section of the trip where it will be very cold... with an altitude that could go get as high as 6000 meters.
I’m pretty sure that my 2 batteries will not be enough... and that I should think of a simple way of getting more energy during the trip.
So i was thinking about buying a battery grip that could accept AA battery and bring with a small AA solar charger...

Any better solutions???

Thanks for your help
Ben
Note: weight is also a concern for that trip.

There are some foldable solar panels that you could consider. Check if the battery charger could connect. Here are a couple of story:
Hiking Backpacking Charge/Recharge iPod EL8 Solar Headlamp Outdoors
http://www.out-bush.com/107/solar-chargers-keeping-your-mobile-charged-while-hiking/

There were some threads (in this Forum) suggesting that the Lithium (non-rechargeable) batteries behave much better in the cold than others, and that rechargeable batteries last less in cold conditions. You might wish to check.

Food for thoughts....

[photocat]

I just picked up this one but I haven't even had a chance to test it out. If it works as advertised, it will be quite an awesome little thing to have handy.

Amazon.com: PowerFilm USB + AA Solar Panel Charger: Patio, Lawn & Garden

[ben_leg]

There is a variety of product that could charge usb device (ipod) and AA / AAA batteries.

What i was hoping for was a simple option to charge the battery of my K7.

Ben

[Aknot]

Rollable Solar Chargers | PowerFilmSolar.com

Little pricey but I think this might be your only option? How many people are going maybe you could share the cost?

[newarts]

There is a variety of product that could charge usb device (ipod) and AA / AAA batteries.

What i was hoping for was a simple option to charge the battery of my K7.

Ben

This should do your AA's in a few hours at a reasonable $40 delivered price: http://cgi.ebay.com/Folding-Solar-Panel-Power-Supply-AA-AAA-Battery-Charg-/3...item5ade0336e7

One could also use a K-7 battery charger made for a 12V automobile charger and a suitable 12V solar panel, I looked on ebay but did not find a reasonable combination (the solar panel output current should be more than the required input current for the charger.)

[Entropy]

This should do your AA's in a few hours at a reasonable $40 delivered price: Folding Solar Panel & Power Supply AA AAA Battery Charg | eBay

One could also use a K-7 battery charger made for a 12V automobile charger and a suitable 12V solar panel, I looked on ebay but did not find a reasonable combination (the solar panel output current should be more than the required input current for the charger.)

"12v" solar panels usually have a far higher Voc - they're designed to be reasonably well matched to lead-acid 12v batteries without anything fancier than a shunt controller for charge limiting. These are good for charging lead-acids but I'd never use one directly with a 12v-input AA charger.

[ben_leg]

"12v" solar panels usually have a far higher Voc - they're designed to be reasonably well matched to lead-acid 12v batteries without anything fancier than a shunt controller for charge limiting. These are good for charging lead-acids but I'd never use one directly with a 12v-input AA charger.

So is it possible to charge a Lithium-Ion Battery (D-LI90) with a 12v solar panel

Thanks in advance

[Entropy]

So is it possible to charge a Lithium-Ion Battery (D-LI90) with a 12v solar panel

Thanks in advance

You would need some sort of method of regulation in between the solar panel and one of the D-LI90 chargers that can accept DC.

Unfortunately the easiest method for doing this is also very heavy - many such panels were designed to directly charge a lead-acid battery, so connecting that in parallel with the solar cell and running a 12v DC charger from that will work well.

I haven't really thought of ways to do this that are lightweight - I own a gigantic (100+ AH) deep cycle lead-acid...

[normhead]

Here's an example of my setup piggy backed on to the battery a friend of mine carries into the bush to run his sleep apnia machine or CEPAC.



A few words of wisdom.

Find a battery charger that uses a 12 volt DC input ( check the labeling on the power supply).
Try running your panel directly in to your battery charger (for AA)

Or, get a 175 watt inverter and just plug in your regular charger. I have a number of possible configurations I use, but the most reliable and efficient is to the 12 solar output to 12 volt charger for AAs. A six watt panel will charge 4 AAs in an afternoon. You have to test first though, not every 12 volt input charger will work with your solar panel and I don't really know why. I just know you have to test your setup thoroughly before you head off into the wild. If you want, I'll take pictures of and post a couple of working setups for you. One that I have used successfully.

[Ex Finn.]

This is why you should never swim in cold water, both gentlemen obviously are suffering from bad cramps. One made it to the shore, other one is still struggling and trying to get out on dry land.

p.s. nice solar-panel setup.

Cheers. Mike.

[Entropy]

Here's an example of my setup piggy backed on to the battery a friend of mine carries into the bush to run his sleep apnia machine or CEPAC.



A few words of wisdom.

Find a battery charger that uses a 12 volt DC input ( check the labeling on the power supply).
Try running your panel directly in to your battery charger (for AA)

Or, get a 175 watt inverter and just plug in your regular charger. I have a number of possible configurations I use, but the most reliable and efficient is to the 12 solar output to 12 volt charger for AAs. A six watt panel will charge 4 AAs in an afternoon. You have to test first though, not every 12 volt input charger will work with your solar panel and I don't really know why. I just know you have to test your setup thoroughly before you head off into the wild. If you want, I'll take pictures of and post a couple of working setups for you. One that I have used successfully.

That's because the open circuit voltage of solar panels is vastly different from the loaded voltage - the 12v charger is expecting a range of probably 10-14 or 15 volts. A solar panel optimized for 12v charging can go as high as 22v when unloaded - this is why I strongly recommend against using a charger designed for vehicle use directly with a solar panel.

[normhead]

I've used a charger designed to be used with a power supply plugged in to a wall. I use it with 6 and 12 watt folding panels rated at 12 volts. But in testing the original power supplies I get readings as high as 13 .5 volts, so they do have some flexibility built in to them. Even when coupled with my buddy's panel to charge his battery, we never went over 14.7 volts unloaded. He's an electrical engineer so we were checking. I'm sure some panels are better than others for this. Mine was designed to recharge 12 volt batterie, so, "never" might be a bit strong. But, knowing your way around a voltage meter will certainly help. I also have checked voltages constantly when a setup wasn't working, and can tell you for sure that wasn't the issue. The fact that some units might produce up to 22 volts, doesn't mean they all do, or that yours does. In any case, a 20$ voltage regulator fixes that problem. They sell them for people using multiple panels, but if you want to play it safe and buy one for your single panel I'm sure it will answer that particular worry. The more relevant problem I think is getting the wattage from your panel to match the output of the power supply that came with your charger. In my case the power supply puts out 750 ma and that seems to work with my panels, as opposed to chargers that cam with power supplies higher and lower than that, neither of which worked in my case. Or it may just be the electronics in the 750 ma charger were more suited for use with a solar panel. My interest ends when I have something that works. Figuring out why one worked and one doesn't, there's not much in that for me.

I don't know the theory. I just know what worked for me.

[cofra]

Buying a bunch of batteries could be an alternative anyhow... considering the weight and space of the total amount of panel, cables and such. For $70-80 you'll get ten more of them on Ebay. 12 batteries will weigh 1080 grams and they will be pretty compact when packing.

I guess you'll be walking during daytime and maybe don't have the time to charge for that long. During night when you have time the sun might not be up.

But in the end it all depends on how much you will use your camera during that time

/C

[ben_leg]

You are right Cofra, I will be walking 6 to 8 hours a day. I'm hopping to get a little bite of charge done with the charger strap on my backpack…. And a little bites more once at the campsite.

If my k7 was the only piece of electronic that was carrying with me, i will simply bring some extra battery and it will solve the issue....

But i want to bring with me a little bite more:
Camera k7 (will need to charge my battery every week or so)
Kindle (the battery should be good enough for the trip)
ipod nano (will require to be charge every other day)
gps (eat about 1 AA every day)
Wolverine back-up drive (will probably need to charge it one during the trip)

Up to now the this (Portable Solar Battery Charger | Portable Solar Panels | Off-Grid Solar Generators | Goal Zero - Extreme Portable Power) seams to be my best option…. But I’m not really sure if I will be able to charge my K7 with it.