Hiking Power pack

lavsan

Need Valuable suggestions.As i am not much of a Mathematician neither electrician.

I go on a lot of multi-day treks.
I am looking at a reliable solar power pack for charging my cellphone, And Nikon D5100 DSLR batteries on the go.

lets assume that We have full power of the sun

Currently i have this in mind

http://dx.com/p/12v-7w-solar-power-panel-auto-car-battery-charger-camouflage-green-165671

The output i need is 5v 2A is it possible to get this Power from this Solar panel if i use a cigarette Adapter as a bridge between panel and my devices.

http://dx.com/p/bullet-shaped-dual-usb-car-cigarette-lighter-adapter-charger-black-12-24v-232331

I need to charge the following battery pack. It will contain 4 x panasonic 18650 batteries (3100 Mah each).
This pack will act as my Power reserve and i,ll use it to charge my devices as and when required.

http://www.ebay.com/itm/3A-2A-Adjust-5-13V-Mobile-Power-supply-USB-18650-Battery-Charger-5V-9V-10-5V-12V-/221261755654?pt=Battery_Chargers&hash=item33843a7506


Thank you in advance.

Photowhit

Re: Hiking Power pack

No basically the solar panels you found are 7w at 12 volt, assuming they are charging/ no threat of over charging panels they are likely 14v panels at 7 watts would be amps x volts = watts so 7 watts / 14v = .5 amps So even if you converted to 5v you can't get to 2 amps with out having 2(and likely more)

It likely would be cheaper and easier and lighter to buy extra batteries and pick them up with your food, pull your cell phone battery when your not using it, since hunting for signal is a very high power drain, your camera battery should last you a very long time, unless you use it continually.

doctorZeus

Re: Hiking Power pack

I'm an FNG around here but feel somewhat educated on this topic since I'm an avid hiker and primitive (hammock) camper and have wondered and answered similar questions. The way I tackled "portable power" sidesteps your solar question, but that's due to my research/analysis pointing to the weight/charge-time/benefit factor overwhelmingly pointing in this direction.

I have over a dozen of these in different size/shape/features but this is the one I use the most http://www.amazon.com/Upgraded-Anker-14400mAh-Portable-External/dp/B005NGLTZQ/ref=sr_1_1?ie=UTF8&qid=1378387844&sr=8-1&keywords=anker+14400 It's 14,400 mah and on a full charge easily tops off my HTC One X (1,800 mah battery) 6 to 7 times, starting with the phone around 10 to 20% charge. The USB ports are the standard 5V for phones, and a third port that toggles 9V/12V, comes with a universal 5.5 x 2.1mm plug and multiple power tips. I've never used a Nikon and am unfamiliar with the required voltages for them, but the 9V option on the above Anker is just about right for the 7.something volt charge my Canon Rebel T3 requires, especially when the battery is at its lower end and the voltage come downs a tad.

I also use it for my telescope when going to "dark sky" sites (and even in the back yard) - the 12V powers the telescope mirror fan along with a 10" DC fan that takes 8 D batteries or an external power source (which happens to be the default 5.5 x 2.1mm cable plug)

There's a ton of these types of batteries out there with different size mah batteries and features..for example I also have a limeade 15600 mah one that doesn't have the 9v and 12v but gives you a little more power for less money ($50 instead of $60). http://www.amazon.com/External-Battery-Pack-Limeade-L156X/dp/B00BZDK3XK/ref=sr_1_1?ie=UTF8&qid=1378389691&sr=8-1&keywords=15600+battery

If you carried one of these you could ditch a few (or all?) of the spare batteries. Something to consider, hopefully this helps!

Cariboocoot

Re: Hiking Power pack

An observation:

Quite a number of hikers/campers get the idea that they can recharge the batteries they take with them with a small solar panel. It seems logical. Then when you figure out how big the panel needs to be to do this it often works out to be easier/cheaper/lighter to carry spare batteries instead.

Someplace along the power need/recharge need curve is a tipping point for what is practical. Exactly where that is will vary on a case-by-case basis, but it is safe to say the fewer power-consuming items you plan on taking with you the easier it will be to bring along a solar panel capable of recharging them.

lavsan

Re: Hiking Power pack

Photowhit wrote: »

No basically the solar panels you found are 7w at 12 volt, assuming they are charging/ no threat of over charging panels they are likely 14v panels at 7 watts would be amps x volts = watts so 7 watts / 14v = .5 amps So even if you converted to 5v you can't get to 2 amps with out having 2(and likely more)

It likely would be cheaper and easier and lighter to buy extra batteries and pick them up with your food, pull your cell phone battery when your not using it, since hunting for signal is a very high power drain, your camera battery should last you a very long time, unless you use it continually.

If that is the case then how can this 3w Solar panel producing .80 Amp at approx 4v (that's what i understood from the video)

http://www.youtube.com/watch?v=7hTIapgKV68

Cariboocoot

Re: Hiking Power pack

lavsan wrote: »

If that is the case then how can this 3w Solar panel producing .80 Amp at approx 4v (that's what i understood from the video)

http://www.youtube.com/watch?v=7hTIapgKV68

Without even looking at the video: 0.8 Amps * 4 Volts = 3.2 Watts.
Photowhit's math is the same: 0.5 Amps * 14 Volts = 7 Watts.

The thing is without being able to down-convert the higher Voltage into Amps all you get is the current, so that panel with specs of 14 Volts and 0.5 Amps when used at 5 Volts still only produces 0.5 Amps or 2.5 Watts. Not 2.5 Amps.

PNjunction

Re: Hiking Power pack

Carrying spare batteries for a multi-day hike is the way to go, unless you have a lot of companions to carry all the solar gear.

Two major mistakes are made about solar and hiking. 1) is not knowing the difference between solar-insolation hours and mere sunrise-to-sunset hours. Just because the sun is shining does not mean panels will be working at any great efficiency to make it worth the effort. Typically solar-insolation hours are between 10a to 2pm, and specialized charts will show variations above and below these generic hours.

2) Charging while on the go, such as hanging a panel off your backpack as you hike is also extremely inefficient.

Basically, to do solar right while hiking, you need to turn it into stationary camping setup to get a decent charge.

If you still want to head down this path, avoid the cheap boutique solar panels, and budget for real battle-tested products from the likes of Powerfilm. But that means large foldable panels, charge controllers, and batteries to charge while stationary. If you tend to camp more than hike, then perhaps this might be something to look into. If it comes to saving your life, then perhaps spend the bucks for the good stuff.

It looks as though you want to charge things directly from a panel, and not through an intermediary battery. For example, to charge your 18650's, you would want a panel, charge controller, an intermediary battery such as a sealed agm, and a custom 18650 charger. If your existing charger can accept dc, then you are ahead of the game. That's a lot of gear to go hiking with.

There are plenty of cellphone solar chargers out there, but the one I found to have the largest panel vs battery size, made of decent quality, and has different user selectable charge rates for Apple vs others, is the Solio Classic2 (note - the latest "2" model is important as it has a large battery and large panels.) You could charge this up via usb before you go, but know that a full discharge would take about 2 days to replenish via solar IF one has at least 3 hours of solar insolation and you were willing to babysit it each day to keep it angled towards the sun and out of long shadows. Obviously more hours of solar insolation is better. Ideally, do opportunity charging instead of total discharge / charging.

Photowhit

Re: Hiking Power pack

PNjunction wrote: »

2) Charging while on the go, such as hanging a panel off your backpack as you hike is also extremely inefficient.

Basically, to do solar right while hiking, you need to turn it into stationary camping setup to get a decent charge.

I just was day hiking on the AT so to help make the point, here's 'The big funny looking guy' with 2 beautiful women, my niece and sister(they have to hang out with me:cool: ) I wore a hat since I'm folicly challenged, but not a lot of sunshine out there.
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