Looking for a good hiking solar panel

[Lawn Sale]

I have a few solar panels now, but they're not really designed for hiking, rather a base camp. That said, I am doing the HMW (Hundred Mile Wilderness) in August and want something that will charge some AA batteries and my iPhone 4S since the iPhone (with SPOT Connect) will undoubtedly need a recharge. I cold bring an external battery pack, but they tend to be a tad heavy. I have looked into quite a few solar panels and read the reviews, but am looking for real-world experiences. This would be something strapped to a pack, on a trail with some cover, so setting it out in the sun like it's Arizona won't cut it. I don't want to go hog wild and spend $500 on an array, but something a little more manageable.

Curious to what people have, use, or have experience with. Thanks.

 

[Maineman]

On the PCT last summer I encountered many thru hikers very unhappy with their solar panels despite virtually unlimited sun.

I used a brunton inspire 3200 battery back which was small and pretty light and provided two + full charges from 0-100%. Pretty fool proof.

Imho, the 100 miles (and most places on the AT) arent suited to using a solar charger.

 

[Maineman]

Also, I did a SPOT check-in once a day for six months and only had to change out the batteries twice.

 

[Maineman]

This model was recently listed on Cool Tools, and they screen their listings carefully. If you check the item's Comments section over the next week, the postings may help in your decision.

Like many models, this uses a battery pack AND the panel. I don't see the point of dragging a panel around, dealing with keeping it angled properly and not scratching it when all you need is the battery pack itself.

 

[Lawn Sale]

I have no problem bringing a smaller battery pack that is charged and then the charge downloaded at night, but a large one I know can weigh a bit. I have a 15,400mAh Lithium polymer battery that will charge my iPhone quite a few times, but it's exceedingly heavy to be taking on the trail. I have a smaller one, I think it's 2,500mAh but after one download it's done and I only use it on overnights.

 

[peakbagger]

Considering the large number of tech folks on the site, this is probably not news, but the solar panels generally available on the market are not well suited to mobile backpacking applications. Although many tech reports on the web repeatedly shout out new solar cell efficiencies the "standard panels" (monocystaline silicone) generally available on the market are at best around 18% and polycrystalline panels are in the 14 or 15% range, flexible panels are even less efficient. Considering that Mono and Polycrystalline panels are somewhat fragile, odds are the backpacking panels are 10% at best. The somewhat optimistic solar isolation is 1000 watts per square meter entering the panel. That's is in perfectly clear sky with the panel perpendicular to the suns rays. Multiply this by the cell efficiency to get the best case power output and then figure out how much you lose by the panel being tilted. The efficiency also degrades as the temperature goes up. I will let others do the math but an I phone size panel clipped to the top of pack in a mixed canopy with less than optimum angle is not going to put out a whole heck of a lot of power. Take the same panel and lay it on a flat surface aimed directly at the sun for an entire day and it still doesn't crank out much. Hot hazy weather really does a number as the panels are hot and the sun insolation is reduced.

I am not downing solar panels, I happen to generate all my own power with solar and run a yearly surplus with the utility but many folks just don't understand the basic physics and fall victim to "gadgetitus" then again as Solyndra, or more locally Konarka reinforced even the DOE sometimes likes to fund the new gadget

 

[Maineman]

Just curious, what do you do with your phone while hiking that you need to recharge it on an overnight?

I listened to 2hrs of music/podcasts a day, took lots of videos & photos, used it for GPS, typing my journal everynight plus Spot check-ins and only needed to recharge once every five days.

To extend the battery life I kept it in airplane mode most of the time, turned bluetooth on/off when sending Spot check-ins and kept brightness at 50%.

You had asked for real world experiences and I saw many people (at least ten) frustrated with their panels - despite careful research in advance. Ironically the model that people hated the most (the Solio Bolt) was Backpacker Magazines "Editor's Choice"!

 

[Lawn Sale]

I understand completely where you are coming from, peakbagger, we have two discreet Outback solar arrays at work we have to maintain, diagnose, repair, and adjust based on seasonal variability.

What I am looking for is honest 'does it work or is it junk' analysis, I have read many reviews on sites and most places don't even give the specifications, just that it can 'charge your smart phone 2 times in a day!'. That means nothing to me as a consumer and even less as an engineer and natural skeptic.

I just didn't know if anyone used them and what experiences they had.

I have a Solarport 4.4 and it's a good unit for base camp, but it's too heavy for hiking.

Maineman, I usually keep it in Airplane mode and just haul it out to take pictures with it. Even then, it'll only last 2 days at maximum, and I don't listen to music on the trail, instead preferring the natural sounds around me. When using SPOT, I always turn on the BT and then turn it off after. On occasion I will read a book on iBooks at night before sleep, but that doesn't take much power since the book is already loaded.

 

[Maineman]

Hmmm, I'd look into having your battery tested at an Apple store - two days of taking photos should not drain your phone.

As an aside, a lot of through hikers chose Android phones for the swappable internal batteries.

Have a great time on the 100 miles - what a great trip!

 

[Maineman]

Just checked in with the person I met who DID have good luck w/ their panel.

He used the Goal Zero Nomad 7 without using the battery pack. iPhones work with a trickle charge, and under the relatively open terrain of the PCT he was able to keep his phone full by leaving it connected to his phone throughout the day with the panel affixed properly. Remembering to face the panel directly at the sun during breaks was helpful, along with being very careful not to scratch it.

He said that some phones (older iPhones & others?) did not support trickle charging and didn't work well.

Hope this is helpful, I don't want to come across as a negative nancy...

 

[Lawn Sale]

Many thanks, Maineman. I did have it tested at the Apple store because I also thought it went down faster than it should, but they said it was normal. I haven't really noticed a lot of battery drop differential over the last year or so, but I do use it for more than just a phone a lot of the time.

No way I'm going to switch to an Android phone, that's like buying a new car for a trip because you may need to top up the oil on the old one.

I read a lot of reviews on the Nomad7, but there were a lot of negatives regarding iPhone useage, most of which said it was 'flakey' because if you walked in front of the solar panel, the charging would be interrupted and you'd have to manually restart it again, which I didn't want to deal with.

 

[ChacoTaco]

While its not a solar panel, I just started using the i torch by newtrent. The itorch charges an iphone or smartphone up to 3 times and that is if the battery completely dies. They have higher capacity chargers as well.

http://www.newtrent.com

 

[Guthook]

Like Chaco Taco, I've been using a battery pack for my iPhone (Anker Astro, similar to the New Trent). Solar doesn't make sense for east coast backpacking, especially the 100 Mile Wilderness, which is very much a green tunnel for most of the time. I get nearly three full charges of my iPhone 4 from the Anker, and I don't have to worry about finding sunshine and waiting for a solar panel to collect sunlight.

If you're determined to use solar, though, I've heard good things about Suntastics, which several PCT hikers seem to be using right now.

 

[JJD]

IIRC, the solar panels aren't that light either. I don't know if it would really be a huge advantage in weight over the battery pack. My 10,000 mAh pack (Anker) doesn't weigh all that much.