Help- New- Need Solar Power for Hiking Trip

[bjohnson]

Hello,

My dad and I are going on a very long hiking trip and are trying to figure out the best way to power our electronics. We need to be able to document our trip- meaning powering a small laptop for 2 hours a night, recharging a GoPro camera, recharging our phones, and powering a portable wifi hotspot if need be. We know very little about solar power, but figured it would be the only way to do what we need. My dad is very handy- should we try and build a DIY system, or is there a system that we could buy that would suit our needs? We realize these things are solid, but the lighter the better. We'll have a pull behind cart for our heavier items. Any help would be greatly appreciated.

[inetdog]

Hello,

My dad and I are going on a very long hiking trip and are trying to figure out the best way to power our electronics. We need to be able to document our trip- meaning powering a small laptop for 2 hours a night, recharging a GoPro camera, recharging our phones, and powering a portable wifi hotspot if need be. We know very little about solar power, but figured it would be the only way to do what we need. My dad is very handy- should we try and build a DIY system, or is there a system that we could buy that would suit our needs? We realize these things are solid, but the lighter the better. We'll have a pull behind cart for our heavier items. Any help would be greatly appreciated.

Unfortunately it it not realistic to expect to collect much solar energy while you are actually hiking. Keeping the panel correctly oriented toward the sun and out of shade can be difficult. And by the time you stop for the night there will be very little sun left.
The first thing you need to do is calculate the total energy you will need per day. If you go from full charge to zero charge on a typical smart phone in one day you will have used about 5 watt hours of energy. If you had a 12V panel with an efficient voltage converter to charge your phone battery, you would need a 10 watt or better panel that is aimed directly at the sun for at least an hour during the period within an hour or so either side of solar noon.
If you plan on stopping for lunch and a siesta around noon, you might be able to take care of two phones and perhaps the camera with a 40 watt panel. The laptop will take much more power, probably on the order of 20 watts with the display backlight kept very low. So that will be 40 watt hours. If you need a wifi hotspot, use the hotspot capability of good recent model smart phones.

Oh, and welcome to Solar Panel Talk!

[SunEagle]

I second inetdog's suggestions. Using a solar panel to charge batteries during a "hike" will not get you enough due to movement of the panel.

There are now some relatively inexpensive portable (5000mah and larger) batteries that are not heavy and can be used as a USB "charging source" for small loads like cell phones and iPads. Not sure if they would be big enough for some laptops which can use a lot more power. It all depends on what your "watt hour" demand will be to recharge your electronics.

Finding a lightweight 25watt folding solar panel for charging will end up costing you about $300 and provide minimum about of charging capabilities. Bringing a 40watt or larger rigid panel on the hike might be heavy and unless you stop during "peak" sunlight times to aim the panel and do your charging it could be pretty useless for the rest of the hike.

IMO it might be better to spend $200 and load up with a few of those 5000mah batteries.

[Amy@altE]

I'm not going to give an opinion on these, but I do know they are out there. Of course they would work better hiking across the plains than through the forest. http://www.voltaicsystems.com/ But it does have tools to help figure which size you need depending on what you are charging, so at minimum that might be helpful for ideas.

[SunEagle]

I'm not going to give an opinion on these, but I do know they are out there. Of course they would work better hiking across the plains than through the forest. http://www.voltaicsystems.com/ But it does have tools to help figure which size you need depending on what you are charging, so at minimum that might be helpful for ideas.

Interesting technology. I like the V44 12,000mah and V72 20,000mah batteries. But all their solar panels come to about $10/watt which is crazy expensive.

[bjohnson]

Thank you all so much for your help! I'll probably end up either stocking up on small USB chargers, or getting one of those mobile kits. The Voltaic kits might be exactly what I need.

[Amy@altE]

Interesting technology. I like the V44 12,000mah and V72 20,000mah batteries. But all their solar panels come to about $10/watt which is crazy expensive.

$10 a watt is crazy for a big grid-tied panel, but about right for the little flexible portable ones, similar price for the Sunlinq foldable ones. http://www.globalsolar.com/products/retail/sunlinq-4

We've got a 10W silicon cell, glass front, aluminum frame for $5 a watt, but I wouldn't want to strap it on my back while hiking, not to mention the 4.2 pounds it adds. It's all about what you are willing to pay for convenience, lightweight, plug and play, etc. But these probably won't last as long as a traditional one, so again, what's the priority? I used to hike with someone who removed the tags from his tea bags when packing for the trip, because he didn't want the weight of the tag. I know he'd pay more for lightweight.

[SunEagle]

$10 a watt is crazy for a big grid-tied panel, but about right for the little flexible portable ones, similar price for the Sunlinq foldable ones. http://www.globalsolar.com/products/retail/sunlinq-4

We've got a 10W silicon cell, glass front, aluminum frame for $5 a watt, but I wouldn't want to strap it on my back while hiking, not to mention the 4.2 pounds it adds. It's all about what you are willing to pay for convenience, lightweight, plug and play, etc. But these probably won't last as long as a traditional one, so again, what's the priority? I used to hike with someone who removed the tags from his tea bags when packing for the trip, because he didn't want the weight of the tag. I know he'd pay more for lightweight.

I agree that it is sometimes ok to pay more for convenience and portability as long as the hardware is worth it. In most cases someone perceives the item it worth the extra cost but the quality is much less and they end up greatly disappointed.

I purchased an 80 watt folding solar panel with a 10amp charger and cabling for a little over $3/watt. Added a 65Ah Optima battery, battery box, hand cart and 300watt inverter. It does work for me when I need just a small amount of power and charging capacity for "field" projects but is not really that portable when you add the weight of the battery. I still struggle with what I spent for the entire system (~$550) when I could have purchased a small inverter style generator which is also portable and provides 1000 watt of power for hours instead of a few hundred watts like my system.

Small Portable PV sys pic3.jpgSmall Portable PV sys pic2.jpgSmall Portable PV sys.jpg

I guess it comes down to what someone is fine spending their money on.

[PNjunction]

Interesting technology. I like the V44 12,000mah and V72 20,000mah batteries. But all their solar panels come to about $10/watt which is crazy expensive.

Heh, the real spec is what is the wh rating divided by the voltage of your application. Most of the current ratings are at the 5v USB level, so those devices that also do 12 or 18v outputs should derate their current capability accordingly. It's the old (P/I*E) thing. Catches quite a few when the seemingly HUGE capacity only powers a laptop for 10 minutes.

[SunEagle]

Heh, the real spec is what is the wh rating divided by the voltage of your application. Most of the current ratings are at the 5v USB level, so those devices that also do 12 or 18v outputs should derate their current capability accordingly. It's the old (P/I*E) thing. Catches quite a few when the seemingly HUGE capacity only powers a laptop for 10 minutes.

I agree it could be misleading. You have to do the math on how much of a charge you will get.

Yet that 20Ah battery that will charge a cell phone is a whole lot cheaper to have instead of those high price flexible solar panels which are maybe get you some power generation around noon time.