# Solar Charger and Eneloops



## Ian2381 (Apr 4, 2011)

Is it safe to use Solar charger to charge eneloop AAs or does it have negative effects? i just bought a cheap solar charger and Im reluctant to use my eneloops. I also saw a solar panels with a AA holder to charge batteries.


----------



## Mr Happy (Apr 4, 2011)

Check the maximum charging current. If it is less than 200 mA for AA cells, or less than 80 mA for AAA cells there is no problem. If the current is up to 350 mA for AA cells, there is still not much of a problem, but you should check the cells and remove them when they are charged (i.e. when the voltage has reached 1.5 V). Note that solar cells only deliver full output in direct sunlight, so to charge AA Eneloops at 350 mA would require six hours of direct sunlight at least.


----------



## Teobaldo (Apr 7, 2011)

Is better use a solar panel for energize a battery charger, this configuration has worked fine for me. A simple solar charger works too (and is more cheap), but you should be attentive to it indicated by Mr.Happy, because can burn the batteries upon overcharging them.


----------



## pblanch (Apr 10, 2011)

Oh dear.

I have a http://www.voltaicsystems.com/amp.shtml which is awesome at charging my ipod touch, wireless hotspot and a few items and was going to use it in conjunction with http://www.energizer.com/usbcharger

The Energizer USB charger that states on the back output 1.4V 550mA . I haven't used the USB Enloop charger anyone got one and what does that say as the output.

Or is the 350mA as Mr Happy quoted per battery? 

I love my enloops and don't want to damage them.


----------



## Mr Happy (Apr 10, 2011)

You don't need to worry if you are using a solar system to power a battery charger like the Energizer one. My advice concerned directly connecting a solar panel to a battery or batteries without a charger in between. 

Using a solar panel directly could be a more efficient option if you match voltages appropriately but it needs technical knowledge and requires manual charge monitoring. But as Teobaldo said, using a solar panel to drive a battery charger is the simpler and safer way of doing things.


----------



## pblanch (Apr 10, 2011)

Thanks Mr Happy. I though I was pretty smart with my USB and solar panels and would have been mortified if they were damaging. 

_Tiefer, tiefer, irgendwo in der Tiefe gibt es ein Licht_

Either your German or a Kate Bush fan Fan (or just like poetry)


----------



## coachclass (Apr 13, 2011)

Just to clarify the posts here about putting a battery charger between the solar charger and the battery cell...

Would it have to be be a dumb battery charger? I can't imagine something like the LaCrosse would work well with intermittent wall power. And your solar panel setup would need some kind of rectifier to convert the power for 110 VAC wall power, right?


----------



## Mr Happy (Apr 13, 2011)

coachclass said:


> Just to clarify the posts here about putting a battery charger between the solar charger and the battery cell...
> 
> Would it have to be be a dumb battery charger? I can't imagine something like the LaCrosse would work well with intermittent wall power. And your solar panel setup would need some kind of rectifier to convert the power for 110 VAC wall power, right?


The battery charger needs to run off low voltage DC power, such as a 12 V (car) or 5 V (USB) input. And it can't be intermittent, it must be continuous (unless you are doing a low current timed charge). That means your solar supply needs continuous sunlight, or it must have its own battery to store the sunlight, such as the one linked by pblanch.


----------



## Bolster (May 12, 2011)

Also looking for a way to charge eneloops on solar. Opinion of the Sundance Solar? 

http://store.sundancesolar.com/poaafosobach.html

Possibly safe if you make certain to charge 4 cells at a time? (300 mA rate in that case). However this wouldn't solve the "intermittent" problem of cloud cover stopping the charge in the middle. 

Regarding the idea of a solar panel powering a battery charger...what solar panel could you recommend that would power the Eneloop charger that comes with the cells?


----------



## Teobaldo (May 12, 2011)

Sundance Solar have good solar stuff, but this charger (to where I know) it is not intelligent and one has to be attentive to not overcharge the batteries.

Y recommend a solar panel of at least 10 Watts (above 800 mA) to powering a battery charger, but I do not know if the Eneloop charger has some car adapter to which to connect it. Perhaps the best be to charge a battery as the Xantrex and later to connect the charger to her to avoid the problem of the clouds.


----------



## stockae92 (May 12, 2011)

*Solar charging system for camping?*

Is there an off the shielf solar panel/charging system like this. I wanted to use it when I go camping to charge up AA, cell phone, etc.

- solar panel(s) can be rolled up or folded so that it will take up a smaller area
- weather proof (at least dust proof I guess)
- able to deliver enough juice (Am?) to charge 2 to 4 AA NiMH in maybe 4-6 hours of sun light
- USB? regular plug?

Thanks


----------



## netprince (May 12, 2011)

*Re: Solar charging system for camping?*

I have one of the 4AA powerfilm chargers, it is nice, I used it several times and now its in safe storage.

http://www.powerfilmsolar.com/foldable-solar-chargers/foldable-products.php

EDIT: Since the threads were merged, I'll add that the sundance 4AA charger I have does have a charging circuit with end of charge termination. IIRC there was more information in the manual.


----------



## Norm (May 12, 2011)

*Re: Solar charging system for camping?*

Thread merge:
Solar Charger and Eneloops 
Solar charging system for camping?


----------



## Stagdag (May 15, 2011)

Hey guys, thread bump!

Is there any major difference between the more expensive portable (roll-up) solar panels and the more stationary, "blocky" ones?

I'd like to invest in a solar panel in order to charge eneloops and NICAD/NIMH batteries.

But I don't want to fry em or stop the charge in the middle?

I take it from the previous posts that in most climates, one needs a separate self-powered trickle charger with its own power source?

What are some good brands for this, currently?

Thank you for your help!
PMZ


----------



## SMC527 (May 18, 2011)

*Re: Solar charging system for camping?*



stockae92 said:


> Is there an off the shielf solar panel/charging system like this. I wanted to use it when I go camping to charge up AA, cell phone, etc.
> 
> - solar panel(s) can be rolled up or folded so that it will take up a smaller area
> - weather proof (at least dust proof I guess)
> ...


 

this is exactly what I am looking for as well (in my thread on batteries for extended wilderness stays)

I don't know anything about "thread merging" but if that is appropriate here, please do it.

I am leaving for AK on 7 June 2011 (Tuesday). I am mostly concerned with being able to charge AA size batteries (for a GPS and a Camera) but would also like to be able to charge my cell pone as well (there are some areas where I will get coverage)

Please point me in the right direction as to the items (everything-including batteries) that I need to obtain to have this ability.

thanks!

SMC


----------



## glockboy (May 18, 2011)

*Re: Solar charging system for camping?*

Look at the Cottonpickers Solar Powered & USB Chargers.
http://www.cpfmarketplace.com/mp/sh...Solar-Powered-amp-USB-Chargers-2-panels-added


----------



## SMC527 (May 18, 2011)

*Re: Solar charging system for camping?*



glockboy said:


> Look at the Cottonpickers Solar Powered & USB Chargers.
> http://www.cpfmarketplace.com/mp/sh...Solar-Powered-amp-USB-Chargers-2-panels-added


 

How durable are these chargers? Are they waterproof (or at least splash proof). How susceptible are they to damage?


----------



## Samy (May 19, 2011)

*Re: Solar charging system for camping?*

I recently bought a 'smart' charger designed for eneloops. It individually charges 8 eneloops in around 2-3 hours and comes with a house plug and a 12v car adaptor. The input of the charger is rated at 12v 1.7amps:








I'll probably get something like this which is very popular downunder - a folding solar panel designed for campers and emergency use at home in case of extended blackouts. They're a bit on the $ side but they come with a 12 volt regulator and alligator clips so they're ready to go and fold up with all the cables & regulator inside so it looks like a small briefcase. They come in all sizes so all i need is a small panel rated at 40w/2amps with a cigarette/car socket so i can use the cigarette/car plug that came with the charger but i'll probably get a longer lead to keep the charger itself out of the sun. This way i'll be using a fully automatic, temp & volt controlled charger the way it's supposed to be used and all i need is a 40w 2amp solar panel to plug it into. I should be able to charge a full set of 8 Eneloops in 2-3 hours so it doesn't need to be out there all day. At home, I should be able to leave the eneloops charging on the bench in the garage or in the house and run a lead outside to the solar panel which i can place beside the house/garage or on the lawn in the backyard.  Apart from the purchase price of the panel (which has a 10 year warranty) it won't ever cost me anything to charge my eneloops as long as the sun is out 

This is a 40watt, 2.2amp self contained solar panel with 12v regulator:











cheers


----------



## SMC527 (May 20, 2011)

*Re: Solar charging system for camping?*

Bump for further direction on a charger/Battery set up that could be used for eneloops on an extended wilderness expedition


----------



## asval (May 21, 2011)

*Re: Solar charging system for camping?*



SMC527 said:


> Bump for further direction on a charger/Battery set up that could be used for eneloops on an extended wilderness expedition


 
Don't get what you mean by charger/battery unless you mean that you'd like to have a separate battery to store any surplus power. If that's the case I'd just bring more eneloops along, unless you're going to be in really cold weather in which case a lithium power pack might be good. 

Another recommendation to check out cottonpickers thread in the marketplace as there's lots of good info there. 

Here's a unit that was posted there which I'm considering buying since it seems more robust, but the 1 year warranty and $$$ is making me wonder if it'd be better to just buy 2 of his units.

http://www.suntactics.com/

Here's his reply to the unit. 

That first panel is great. Its like mine (5v) so perfect for usb. What it says is accurate about not needing conversion from 12v. Its got 20% more power than my xxl. Obviously its twice the price without the chargers & postage but is one of the few real usb chargers around.


----------



## SMC527 (May 22, 2011)

*Re: Solar charging system for camping?*



asval said:


> Don't get what you mean by charger/battery unless you mean that you'd like to have a separate battery to store any surplus power. If that's the case I'd just bring more eneloops along, unless you're going to be in really cold weather in which case a lithium power pack might be good.
> 
> Another recommendation to check out cottonpickers thread in the marketplace as there's lots of good info there.


Forgive me, but I am still having a hard time deciphering what I need from these posts (Apparently I am about a smart as a fencepost, because I keep getting confused in the numbers....)

I know nothing about electronics and very, very little about electrcity

I will be spending 2 to 3 months (at least) in the Alaskan wilderness starting the second week of June 2011. I will have very little access to resupply

the electronic devices which I am taking are as follows:

*AA Battery powered devices*
Garmin 60cx GPS
Browning Headlamp
4sevens flashlight
nitecore flashlight

*CR123 Battery powered devices (these will not see much use, but I will have them with me)
*Surefire G2 with LED lamp
Surefire X300

*USB Charged Devices (battery type unknown-neither of these will see much use, but it would be great if I could power them)
*Driod X
HP Pavilion Laptop

Additionally, I may have access to a motorboat with a 12v deep cycle battery (used to operate the trolling motor) and if I could charge that as well, it would be a huge bonus (but that is last on the list of priorities)

I am looking for a complete "set up" to be able to do the above- I have no rechargeable batteries, no chargers, nothing.......

I would like the equipment to be as durable as possible (as I may be staking my life on it) and as packable as possible as space it always at a premium

Any assistance I can get in deciphering exactly what I need would be a huge help. Cost is a minimal factor, having it in my hands by 6 JUNE 2011 is a requirement.

thanks for your patience. 


SMC


----------



## Mr Happy (May 22, 2011)

*Re: Solar charging system for camping?*



SMC527 said:


> I am looking for a complete "set up" to be able to do the above- I have no rechargeable batteries, no chargers, nothing.......
> 
> I would like the equipment to be as durable as possible (as I may be staking my life on it) and as packable as possible as space it always at a premium
> 
> Any assistance I can get in deciphering exactly what I need would be a huge help. Cost is a minimal factor, having it in my hands by 6 JUNE 2011 is a requirement.


There's really not that much power in sunlight to power up and charge a lot of things. Just think for a moment of solar garden lights and how feeble they are.

IMHO you have left it too late and are being too ambitious. Given your lack of prior experience and knowledge in this you should have sorted out your plans and been testing the gear many months ago.

As it stands, I'd suggest electronics do not belong in the wilderness and you should pare down what you take to the minimum. For lighting, I'd propose taking just a couple of lights that have a low low mode that runs for days and take a stock of spare batteries. (Maybe CR123A powered, since these batteries are small and light.) Rely on daylight for doing stuff and sleep when it's dark. Have some emergency lighting like glow sticks as backup.

If you must have the GPS, keep it switched off and use it only in emergencies to conserve the batteries. Use paper maps and a compass for most of your navigation.

The camera is the tricky one. If it runs off AA batteries, I think I would take a stock of spare Energizer Lithiums for it and try to make every picture count.

Don't take big stuff like laptops or netbooks, however appealing it may be.

In fact, I think that taking a bundle of spare CR123A and AA lithium batteries would be your best option. Recharging off the grid is complicated and technical and you are not going to get that sorted out in the next couple of weeks.


----------



## Lynx_Arc (May 22, 2011)

*Re: Solar charging system for camping?*



SMC527 said:


> <content removed to shorten quoting>
> I will be spending 2 to 3 months (at least) in the Alaskan wilderness starting the second week of June 2011. I will have very little access to resupply
> 
> the electronic devices which I am taking are as follows:
> ...


 
OK first thing, is ALL your equipment USB chargable or just a few things? I don't think an HP laptop can be recharged via USB but I could be wrong. I figure a few things *may* need a 12v source which could be your trolling motor battery. You could get a 12v solar charger to recharge that battery and include enough output so it can also recharge devices that won't recharge via USB but can or could be adapted to recharge via 12v. A separate USB setup for everything else would then handle the rest. I would also consider a 12v to USB adapter so you could in a pinch recharge USB items off your 12v solar setup + trolling motor battery. 
Now for the USB setup... you need to calculate as close as possible ALL the batteries/week used in every device and decide if they require charging or not. I was going to say per day but using a week and dividing by 6 would probably be a better way to estimate. You could even divide the week total by 5 and give yourself a larger margin of error. You have to remember that if weather gets bad or something happens you could go a day or two without recharging so have extra batteries (primaries even) in case. If I was going to go 2-3 months I would consider cottonpickers daisy chained panels design and instead of buying a 1 panel to do it all by two panels that do a little more than the one panel that you can either connect or use separately. This would allow for one panel to fail or be out of service and you would still be able to manage at a somewhat less comfort level. The two panel idea would be if you don't go with a 12v and usb panel setup. Redundancy is a good thing IMO.


----------



## SMC527 (May 22, 2011)

*Re: Solar charging system for camping?*

Thanks Lynx Arc,

If I had to pare it down to bare bones I would say the AA items would be what I would absolutely need, everything else is luxury. If I can not get a solar charger set up I will do what I did in 2000 (when I was in the bush for 8 months) and pack a lot of regular disposable batteries (I believe that is what you mean when you use the term "primaries." Is that correct?) It is doable, but a pain- If I am able to go solar, that would be my preference

At the top of that "luxury list" would be my Droid X. 

if I am understanding you correctly, you suggest 2 of cotton pickers panels. Is this correct? What size, if I were to use only one, would you suggest? Can you speak to their durability? I will likely get 2 of the suggested size, as I totally agree that redundancy is a good thing ( I am taking a backup of almost everything)

what do you mean by "daisy chaining" them?

I suspect to use about 10 AA size batteries a week AT MOST. It will more likely be half that. Light will not be an issue for most of the trip due to the fact that it is daylight for 20+ hrs. It will mostly be for photos and navigation, but the GPS will be used only for confirmation if the course appears to be incorrect, and obviously the camera is the least important item.

I really appreciate the assistance


----------



## Mr Happy (May 22, 2011)

*Re: Solar charging system for camping?*



SMC527 said:


> if I am understanding you correctly, you suggest 2 of cotton pickers panels


Mr Negative here again...sorry to be a downer on all this stuff. While cottonpicker's merchandise looks like very nice gear, the items appear to be shipped from the UK. Why is that important? Well since about November of last year, packages mailed from the UK to the US may take 2-3 months to arrive. This is due to the US government messing up the postal service following the "bomb in a printer cartridge" event of that time. I'd say there is no chance you'll get them in the next two weeks (unless you request expedited shipment by FedEx or something).


----------



## SMC527 (May 22, 2011)

*Re: Solar charging system for camping?*



Mr Happy said:


> Mr Negative here again...sorry to be a downer on all this stuff. While cottonpicker's merchandise looks like very nice gear, the items appear to be shipped from the UK. Why is that important? Well since about November of last year, packages mailed from the UK to the US may take 2-3 months to arrive. This is due to the US government messing up the postal service following the "bomb in a printer cartridge" event of that time. I'd say there is no chance you'll get them in the next two weeks (unless you request expedited shipment by FedEx or something).



Understood-Is there a readily available alternative. I have seen all types of flexible chargers for sale, along with several other rigid chargers including some mentioned in this thread. What can I get in time that will work for AA (even if they are not eneloops) and possibly a droid X?

this is one of the final "pieces of the puzzle" so to speak. A "refinement" from carrying throwaways


----------



## Mr Happy (May 22, 2011)

*Re: Solar charging system for camping?*



SMC527 said:


> Understood-Is there a readily available alternative. I have seen all types of flexible chargers for sale, along with several other rigid chargers including some mentioned in this thread. What can I get in time that will work for AA (even if they are not eneloops) and possibly a droid X?
> 
> this is one of the final "pieces of the puzzle" so to speak. A "refinement" from carrying throwaways


I can't recommend as I don't own any solar chargers. However, the "Sundance Solar" products linked above do seem worth consideration.


----------



## Lynx_Arc (May 22, 2011)

*Re: Solar charging system for camping?*



SMC527 said:


> Thanks Lynx Arc,
> 
> If I had to pare it down to bare bones I would say the AA items would be what I would absolutely need, everything else is luxury. If I can not get a solar charger set up I will do what I did in 2000 (when I was in the bush for 8 months) and pack a lot of regular disposable batteries (I believe that is what you mean when you use the term "primaries." Is that correct?) It is doable, but a pain- If I am able to go solar, that would be my preference
> 
> ...


 
Daisy changing is hooking panels in parallel so the output of them is combined. It would allow for essentially double the output of one panel which could match a panel with perhaps twice the area but the advantage is having two smaller panels and redundancy if one panel fails you have power even though it is only half as both of them. It requires a patch cable setup (he supplies) to connect them together. I am not sure that you can tap off both panels separately to charge when chained together I think you will only have one output but at twice the power it will charger faster and easier in poorer sunlight conditions.
As far as what size to suggest, I have no way to estimate that because I would need to have an idea how many and what capacity batteries would need recharging. If you could figure out how many eneloops a day you use and how often you need to charge other devices and their battery types/chargers/capacity it could be calculated. If you have a lot of daylight maybe you could get along with just a single medium sized panel perhaps.
I saw Mr Happy talking about the shipping not being able to get there in time. That would be the biggest obstacle for sure. Primaries are disposable batteries such as alkaline, heavy duty, CR123, energizer L91 lithium AAs etc.


----------



## asval (May 23, 2011)

*Re: Solar charging system for camping?*



SMC527 said:


> Forgive me, but I am still having a hard time deciphering what I need from these posts (Apparently I am about a smart as a fencepost, because I keep getting confused in the numbers....)
> 
> I know nothing about electronics and very, very little about electrcity
> 
> ...


 

Well not knowing what type of weather you'd be experiencing during your journey makes things a bit trickier. I've also no clue if Cottonpickers stuff can resist the cold conditions brought on by a storm and not to mention the fact that his panels aren't waterproof. That other unit I posted while more robust doesn't list temperature resistance other than "Handles temps up to 160F", but you could try asking him. Here's another unit you might consider which has been tested in tougher climates

http://www.backcountry.com/brunton-solarroll-solar-panel#review_200019224

But this does require something in between your battery charger (aa, lion, etc.) and the panel, so here's a lithium power pack so you can charge it with the panel.

http://www.rei.com/product/800240/brunton-inspire-portable-power-device

you could use the 12v deep cycle battery, but you'd have to be careful not to undercharge the battery or you'll damage it. This is why lithium is preferred in cold weather.

Now all you need is a battery charger of your choice to recharge whatever batteries you'll be using.

Ultimately what you should do is look around the net for other people who have made similar trips and take a look at what gear they tend to favor so that you know what gear has actually been tested under real life conditions. I've always found that kayakers are always a good resource for finding tough gear that has been proven under the worst of circumstances.

Here's another good link to have:
http://batterydata.com/


----------



## Don_Redondo (May 23, 2011)

*Re: Solar charging system for camping?*

Here are a couple extra thoughts. 

1st are you going to have a home base or be on the move? Most solar solutions will be worthless if you will be hiking or frequently moving through wooded areas. Much better if you can leave something setup for an extended period of time. 

2nd solar systems (even portable ones) need to be sized to the demand and realistic amount of sunlight available. How much juice do you need, how often will it need to be replenished, and how many days of sun can you count on when you need it, and what charge rate can the devices take? Since sunlight opportunities in the wilderness can be fleeting, higher wattage panels are often desirable – get the most power in the least amount of time – but at some point they are either to big to carry or more often for small electronics put out more power than can be used. There is a general notion that all things being equal if it takes 8 hours to charge a set of AAs then a panel with twice the area will charge them in 4 hours but it depends on the charge circuit and specific device. That said, a larger array might still be a good match on a partly cloudy days. And always remember that historical average on the number of sunny days doesn’t mean a lot when you find yourself with a week of clouds. (I’ve got solar on my house and know first hand about the occasional extended periods with little or no output. On average it’s fine but….) 

3rd Panel/array types. In general the type of cells used in the fixed panels are more efficient – but also more fragile. The portable ones are more forgiving but you might need more area for the same output and they also tend to be more expensive per watt. For wilderness use the choice is likely more of convenience and durability than which one is more efficient or cheaper. 

4th individual chargers/solutions or reserve power. Getting something to charge a battery pack which can then charge the other equipment might be easier than trying to find something to charge each item or class of items by themselves. You might want to consider something like the energizer energi to go products http://www.energizerpowerpacks.com/my/products/ to hold power that can then be used to charge any of the other items that you have. The XP18000 has 5, 10, and 19V output. Add a USB AA charger and it should work for everything accept topping off the boat battery. This pack can be charged from AC, DC 12V, and presumably any solar array that has ~12V-16V output. This means you could fill it up before you head out, set up a panel to refill as necessary, or even top it off from the boat battery if you find you need your phone more than a boat ride. Energizer also has some smaller units that are more suited for just a phone and one that even has a panel built in. One comment on the built-in models is that you need to have realistic expectations on charge rates. I have a Power Monkey explorer (~2400mah backup phone charge type cell) with a separate small solar panel and it takes 2-3 days full sun to recharge. I used it on an extended sailing trip to keep my phone going and it worked – when the sun was out. 

5th listen to the minimalist advice. If the laptop is for keeping a journal – consider pencil and paper. I second the idea of a light with moonlight mode. Safe-Lights/Palights are excellent for this. They run on 9Vs so it is yet another battery which is not the best idea but they are reasonably compact and they run for a year or more in moonlight mode. They make great nighlights for a cabin or tent and can be used as a flashlight when needed. 

Lastly, if it were me and I was going to be based in a cabin and absolutely needed the laptop, I’d go for a 10watt or higher array ~15V – probably fixed panel as efficient (watts/in^2) as I could afford to keep the overall size and weight down, a XP18000 – or something like it, and a USB AA charger. Without the laptop I’d drop the array to around 5watts and get something like the Duracell mobile charger with the USB out – if you can still find one - excellent travel charger. These will charge AAs or AAAs from AC or 12V (including an array) and then the cells can be used to power the USB port in order to charge the phone and other gadgets. The USB out can even be powered by conventional cells so this charger with a couple sets of rechargeables and some alkaline or lithium primaries would cover the lights, GPS, and USB gadgets. If I were going mobile (no home base), I might consider one of the daypack/backpacks with an integrated solar array but I would certainly not count on it. 

If you just need to recharge AAs, most 12V capable chargers (lots to choose from and several that are travel sized and have an AC option) can be used with a panel/array that is rated at 12V (again lots to choose from) Many panels have higher nominal ratings but drop to around 12V under load so just about anything from 12V- 16V should be OK – although you might need to wire up a connector. Or just pick one up with cigarette lighter jack – a little bulky but very convenient – just plug the charger into the array. Also note that a lot of these arrays can be used to top off the boat battery and likewise a lot of the panels sold to top off car batteries can be used to run a 12V AA charger. 

Let us know what you decide – and eventually how it worked it.


----------



## SMC527 (May 23, 2011)

does a higher wattage rating mean that the charger will charge batteries faster or in poorer conditions? Given my criteria, is there a wattage level that is best? What would be the performance differences between 5 watts and 10 watts? (i.e.-what would I be able to charge with each and how fast?)

I am leaning toward this product
http://www.powerfilmsolar.com/foldable-solar-chargers/f15-600.php

thinking that it would definitely be powerful enough to charge AA and the cell phone. Would it be suitable to trickle charge the laptop?
How about the 12v marine battery? (though the latest info I am getting tells me it is unlikely that I will have access to the powerboat)


----------



## Don_Redondo (May 23, 2011)

As others have suggested it is probably best to find examples that closely match your expected use and follow what others have done. That said here is an analogy that might help explain the various choices a little better. 

Lets say that instead of power you want to collect rainwater (sunlight). This water will be used for drinking, cooking, and cleaning (cellphone, flashlights, laptop). If it rains a fair amount you could probably “drink” by holding a funnel over your mouth (direct charge). It would work but better if you had some storage (batteries) so you find a flask for drinking a canteen for cooking and a Jerry jug for cleaning. The rate at which you can fill these things depends not only the amount of rain available downpour vs drizzle (sun vs overcast) but also on the size of the wide AND small ends of the funnel. The wide end helps collect more of the available rain (watts) but the small end limits how fast the water can go in to the container (charge current). If you want to fill your flask in a cloudburst the water may spill over the top of the funnel before the flask has a chance to fill. (Note there is no reservoir in a panel as there is in a funnel – for this analogy imagine the funnel walls collapse as soon as the rain stops.) Likewise if the small end is larger than the flask opening a lot of the water will go unused. The point here is that the rate at which you can fill the flask (charge the batteries) depends not only on available rain (sunlight/power) and the size of the large end of the funnel (array size/watts) but also on the size of the flask opening (charge current that the batteries can accept) – and having a funnel end that is at or smaller than the flask opening (charge current that is limited by the charger – external or internal in the case of the cell phone). 

In other words the flask opening needs to be matched to the funnel, which needs to be matched to the expected rainfall. Now lets say your current flask takes four hours to fill on a normal rainy day and you want four flasks per day. You could set up another funnel and flask to double the collection or get a flask funnel combination with a larger openings - but on a practical matter – are you always going to be there when the flask is full? If you are only going to be by this filling rig every four to six hours to swap the flasks the fill rate is not as important. (So if you have a AA charger that will charge a set of 4 2000 mah AAs in 4 hours – the best it will do on a panel is 4 hours as long as there is enough current going in (size of the array and available sun). Switching the charger to one that can do the charge in 2 hours will only help if you have enough current (may need a higher watt array than is the first scenario) AND you will be available to swap them out when done.) 

Now most people at this point would say why not fill up the Jerry jug and then pour what you need into the canteen and flask later – and that’s a great idea. (That’s power storage and the idea behind dumping the power into a 12V battery, the energi to go type devices, or even the AA chargers with USB outputs.) Note the filling the Jerry jug still means that you need the right size funnel for the other containers (adapters) but still give you the most options. 

(I’ve left out voltage in this analogy but you could think of all of these containers as balloons of different elasticity. If you don’t have enough pressure (voltage) the balloon won’t fill even if the funnel end fits. On the other hand too much pressure and .)

If you have paired your need down to AAs and USB you need a AA and USB chargers – or a combo. Here’s a powerfilm version solar powered combo for 2 AAs http://www.amazon.com/dp/B001RMBHMK/?tag=cpf0b6-20 a couple of those might work for your gadget needs. 

The powerfilm site recommended 5-10 watt panels for small electronics and a 20 watt panel for laptops. These are additive so if you wanted to run two small devices and a laptop you would might need 30 watts or more total – and a way to monitor progress or store it all. 

If you want storage for the laptop you’ll need something that typically has 19V out and should go with the energi to go – or something like it. Note that the 18000 mah unit has less than half the capacity of a typical laptop battery so it would only provide an hour or so extra runtime when full – and that’s using it for the laptop only. This means multiple charge cycles per day if you use the laptop frequently – or drain it at night and hope to recharge in the day. The laptop battery s the largest container so think of this as using the canteen to fill the Jerry jug. If you empty the jug it’s going to take multiple trips to the collection site with the canteen to fill it back up. 

When it comes to cloudy days you you may never be able to fully recover from depleting your devices from extended cloud cover or travel. As an example if you need 4 AA cells per day you should consider having the capacity to charge 8 per day – because after a couple cloudy days the device batteries and the backups need to be recharged to get back to four in use and 4 on standby - and you can't always charge the storage and the device at the same time - depends on the chargers. And by the 3rd cloudy day.... Just something to think about.

So – once again it all depends on where you’ll be and how you hope to use this stuff. If you want a specific recommendation you will need to carefully determine your expected demand (how much do you expect to use your phone, flashlights, camera, etc – how many AAs per day), will you be using separate storage or want to charge the devices directly, is your “wilderness” situation going to be mobile, stationary, in a field, in the woods – or both, and if you will be by the charging setup while it’s running - able to swap things as they are charged.


----------



## asval (May 23, 2011)

SMC527 said:


> does a higher wattage rating mean that the charger will charge batteries faster or in poorer conditions? Given my criteria, is there a wattage level that is best? What would be the performance differences between 5 watts and 10 watts? (i.e.-what would I be able to charge with each and how fast?)
> 
> I am leaning toward this product
> http://www.powerfilmsolar.com/foldable-solar-chargers/f15-600.php
> ...


 

When dealing with anything electrical you typically want to look at "Amps" mainly to get an idea of what type of power the unit will draw or provide in case of a solar panel. The unit you posted lists operating currents as being 0.6 which I'm guessing would mean 0.6 Amps. As an example cottonpickers XL panels is listed as being 700ma (miliamps) which is equal to 0.7 Amps and "400ma charging per hour". It also looks to be as about robust as his panels so personally I wouldn't buy it over his stuff. They do have rollable panels which are more robust.


----------



## kwak (May 23, 2011)

asval said:


> When dealing with anything electrical you typically want to look at "Amps" mainly to get an idea of what type of power the unit will draw or provide in case of a solar panel. The unit you posted lists operating currents as being 0.6 which I'm guessing would mean 0.6 Amps. As an example cottonpickers XL panels is listed as being 700ma (miliamps) which is equal to 0.7 Amps and "400ma charging per hour". It also looks to be as about robust as his panels so personally I wouldn't buy it over his stuff. They do have rollable panels which are more robust.



Completely disagree.

Watts are a FAR bettter method to use for judging power, used, required.

They may well put out 700mA, but if it's only putting out 1v it's pretty pointless.

Watts are a far better indication.


----------



## Lynx_Arc (May 23, 2011)

SMC527 said:


> does a higher wattage rating mean that the charger will charge batteries faster or in poorer conditions? Given my criteria, is there a wattage level that is best? What would be the performance differences between 5 watts and 10 watts? (i.e.-what would I be able to charge with each and how fast?)
> 
> I am leaning toward this product
> http://www.powerfilmsolar.com/foldable-solar-chargers/f15-600.php
> ...


 
higher wattage is not all to consider with solar panels, If you have too little or way too much voltage then you will either be unable to charge something needing a higher voltage, have to put a boost circuit which will reduce efficiency or in the case of way too much voltage you will lose some power lowering voltage via a linear regulator or buck circuit. I don't know what input your laptop needs but I would guess that you could get a 12v adapter and a 12v solar panel setup. You probably will want a pretty hefty solar panel or it could take a long time to charge it as laptops require a lot more power than AA batteries and usb powered devices. I have seen laptop adapters that are 19v at 2 amps that is 38 watts if you have a ~20v solar panel but using a 12v panel you would need a 12v adapter or a boost circuit that loses perhaps 20-30% or more of your power such that you could end up needing a 50 watt solar panel. The batteries in laptops are typically 2 sets of lithium ion or about 4400mah batteries so a 700ma setup that has to be boosted becomed effetively a 350ma panel and would take probably 20 hours to charge. My numbers may be wrong I am just guessing but it should give you an idea.


----------



## Lynx_Arc (May 23, 2011)

SMC527 said:


> does a higher wattage rating mean that the charger will charge batteries faster or in poorer conditions? Given my criteria, is there a wattage level that is best? What would be the performance differences between 5 watts and 10 watts? (i.e.-what would I be able to charge with each and how fast?)
> 
> I am leaning toward this product
> http://www.powerfilmsolar.com/foldable-solar-chargers/f15-600.php
> ...


 
higher wattage is not all to consider with solar panels, If you have too little or way too much voltage then you will either be unable to charge something needing a higher voltage, have to put a boost circuit which will reduce efficiency or in the case of way too much voltage you will lose some power lowering voltage via a linear regulator or buck circuit. I don't know what input your laptop needs but I would guess that you could get a 12v adapter and a 12v solar panel setup. You probably will want a pretty hefty solar panel or it could take a long time to charge it as laptops require a lot more power than AA batteries and usb powered devices. I have seen laptop adapters that are 19v at 2 amps that is 38 watts if you have a ~20v solar panel but using a 12v panel you would need a 12v adapter or a boost circuit that loses perhaps 20-30% or more of your power such that you could end up needing a 50 watt solar panel. The batteries in laptops are typically 2 sets of lithium ion or about 4400mah batteries so a 700ma setup that has to be boosted becomed effetively a 350ma panel and would take probably 20 hours to charge. My numbers may be wrong I am just guessing but it should give you an idea.


----------



## asval (May 23, 2011)

kwak said:


> Completely disagree.
> 
> Watts are a FAR bettter method to use for judging power, used, required.
> 
> ...



I look at that as more in terms of if the current is compatible or not for whatever adapter you which to use (5v for usb, 12v for cigarette lighter, etc.), but generally I'll look at Amps first to see what my power needs will be and then I'll look at the different options available in terms of what devices I can connect to it or if the power is DC/AC.


----------



## SMC527 (May 24, 2011)

Don Redondo- Thanks for the education! I do not know if you are a teacher/trainer professionally, but you definitely have the skill! have I feel like I have at least a cursory understanding of what the different specs mean.

So is a 10 Watt, 15.4 volt too much push on the balloon for AA batteries and USB devices, and not a large enough "big end on the funnel" for a laptop or (Jerry can) storage battery? 

could you make a recommendation on what I should use for a "Jerry can" or at least the specs I should be looking for?

My anticipated usage will be less than one AA per day. Campsites will either be lake or stream side, so "shade" shouldn't be an issue. Weather is the big variable. Whatever solar charging device I choose, it will be supplemented with enough primaries to get me back to civilization in the event of an emergency


----------

