# Bikepacking with Solar?



## Aushiker (Sep 27, 2007)

Its Sunday, it is hot (heading to 40 C), so not much outside activity so here I am throwing some silly ideas around in my head re off the grid power sources. As my Salsa Mukluk 2 is coming and it has a 150mm OLD fork a dynamo off the shelf is not an option so I am just throwing options around in my head and one of those is solar power to recharge a Anker 15,000 Mah battery.

With a more traditional touring option of racks and panniers I can see a solar panel mounted on the rack, draped over the panniers but with a bikepacking setup I will not have a panniers or a rack which leaves the question of how to mount a solar panel.

As a guide I am looking at most of the time going five days to seven days between main power sources and I use a Garmin Edge 810 that will be the main item needing charging. I also carry an iPad but that gets limited use and can generally survive this time-frame.

mmm maybe thinking about this more just sticking with the Anker or two might be a better option.

Ideas? Anyone have other ideas of on off-grid bikepacking without a dynamo?

Thanks
Andrew


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## SimpleJon (Mar 28, 2011)

I've tried Solar Panels before with rack and pannier and I wasn't too impressed. I think the brand was power traveler, they were borrowed. They worked really well on off days when I could keep them directly in the sun but I couldn't get them to work reliably on the bike, 8 hrs into a 7,800Mah power bank (new) would only give about 20% charge onto a garmin or IPhone. I think it is really difficult to keep them orientated optimally on a mountain bike. It was a couple of years ago so they may have improved.
For bike power generation at the moment I don't think anything beats a dyno hub - but 15,000mah is pushing it, I can charge an iPhone 5, a garmin edge810 and get some charge into a 7,800mah pack (probably 25 to 50%) with a 6W Son 28 and an Ewerks, on all but the steepest days.
You could look at getting a custom axle built up to take a 15mm Son or SP hub, a local machine shop should be able to work something out. cut some notches into a couple of spacers and on the hub so it won't slip and rip the wires out.


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## TheirOnlyPortrait (Dec 30, 2014)

Aushiker said:


> Its Sunday, it is hot (heading to 40 C), so not much outside activity so here I am throwing some silly ideas around in my head re off the grid power sources. As my Salsa Mukluk 2 is coming and it has a 150mm OLD fork a dynamo off the shelf is not an option so I am just throwing options around in my head and one of those is solar power to recharge a Anker 15,000 Mah battery.
> 
> With a more traditional touring option of racks and panniers I can see a solar panel mounted on the rack, draped over the panniers but with a bikepacking setup I will not have a panniers or a rack which leaves the question of how to mount a solar panel.
> 
> ...


Hola Andrew,

I think Salsa sells 135mm forks for Muklulks... but I´d be using "small" foldable solar panels while bikepacking. I´m attaching to my handlebar bag a Goal Zero Nomad 13 (to power a Goal Zero Sherpa 50 & Guide 10+) to power my Suunto Ambit2, smartphone, DSLR camera, Delorme InReach, tablet, & GPS... but I also have a dynamo just in case 

Saludos,
Federico

PS: I´m located close to Patagonia where the sun is REALLY strong... something to do with screwing the Ozone layer


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## Harold (Dec 23, 2003)

Solar-only, I'd be real leery about. You would need a rather large bank of cells to get enough juice with the really suboptimal charging you'd get on a mtb. Ideally, the panels would work best if you could be stationary to charge them, so you get them out into the open with an optimal view of the sun. While riding...you can hang panels on a rear rack, on a backpack, that sort of thing...but you'll not be getting the best charge all the time that way.

Power usage is going to be an important factor, too. How long will your device last on a charge before it needs charged up? A DSLR, I wouldn't be terribly concerned. My Canon battery lasts quite a long time. With a spare or two, you'll get quite a long time without needing to recharge. A fitness GPS that would need a charge every day or two? That's really pushing it. Add a smartphone and its battery needs. Ouch.

I think solar is a good thing to have available, especially if you'll be spending time in one place, basecamping for awhile. But I think it's incomplete enough that having other options is important.

Some other options:
The fuel cell charger that generates electricity on the go ? myFC PowerTrekk
Kraftwerk Fuel Cell Lets You Charge Your Phone With Butane | Popular Science
Depending on power needs and recharge opportunities:
Amazon.com: Anker® 2nd Gen Astro E5 16000mAh Portable Charger External Battery Power Bank with PowerIQ? Technology 2-Port 3A for mini, Galaxy S5 S4 S3, Note 4 3 2, Tab 4 3 2 Pro, Nexus 4 5 7 10, HTC One, One 2 (M8), LG G3, MOTO X G, most other Phones

possibility:
https://www.kickstarter.com/projects/1071086547/ampy-power-your-devices-from-your-motion
Kinetic Chargers | EarthTechling

A lot of this stuff is in the conceptual stage, or prototype stage, but some of these are actually available to purchase and could provide viable options for bike(back)packers with power needs that are not satisfied with portable solar panels.


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## Aushiker (Sep 27, 2007)

Thanks everyone. I am aware that Salsa sells a Bearpaw 135 fork but only in black and they are getting a little harder to get and are very expensive hence deciding to not go that path for now. Maybe 150mm dynamos will come on to the market 

Nate I am aslo very doubtful about solar but thougth it was worth throwing out there in case someone has come up with a solution. I spent a bit of time yesterday looking at power needs and what options I have. I think I may get away with switching my GPS to my Oregon 600 (AA batteries, better battery life) and using the Anker 15,000 mah to provide the rest of my power needs as long as I am careful with use.

Camera will be a P&S or a small MU43 so can carry a couple of batteries if required.

Andrew


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## Harold (Dec 23, 2003)

Yeah, IMO, user replaceable batteries are pretty hard to beat for short and medium length trips. Just carrying spares can do the job perfectly well, and it takes quite a few spares before you match the extra weight of a solar charger.

I think solar really starts to come into its own when you're off the grid for more than a month.


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## TheAxiom (Jan 15, 2015)

Though I'm sure that the OP was being poetic when they wrote about it being 40 degrees and a good day for solar, it is worth keeping in mind that the heat of the sun should not be the lone determinate as most quality solar chargers have heat limits and excess energy can actually hamper panel efficiency, which I know sounds highly counterintuitive. But green energy is like that. 

The short answer to your question can be had with some rudementary back-of-the-envelop calculations: The Garmin 810 uses a 1000 mAh battery at 3.5 volts, which Garmin says offers a run time of 17 hours. We all know that that time is bases on lab perfect conditions in Utopia, so lets cut that down to 12 hours to be conservative. We also use a conservative efficiency loss estimate of 30 percent when charging battery to battery (you'll feel this loss as heat at both batteries). Ignoring the voltage differentials for now, you need 1300 mAH give or take to charge the Garmin from near empty. Your 15,000 mAh battery can do that roughly 11 times (rounding down q
15000/1300), keeping in mind that the voltage will drop off as the Arkel battery reaches 30 percent capacity or earlier, thus increasing charge times with greater efficiency losses. If you get 10 charges out of the Arkel battery, that would yield 120 hours of total GPS time (120x10). If you ran your guide group like a Roman general force marching a legion and did 12 hour days in the saddle, you can easily expect to have your Garmin ready to go for about 8 or 9 day, again being highly conservative and assuming you dont need to boostthe iPad. Bottom line: no solar-only-while-moving will be able to do this for you. 

Longer answer from my experience: On an S24O I took last year in March, I bought out my Goal Zero Nomad 7 gen 1 to try out. After using my cell phone-an LG G2-as a gps all day to camp, I awoke the next morning and hung my phone and panel from a tree to catch the morning sun as it rose andI built a fire to make heat and breakfast. Because of the Qualcomm rapid charger built into the G2, my phone went from 10 percent to full in about 100 minutes Using only the panel. It would have likely been a tad faster, but I had to keep rotating the panel to keep up with the sun as it rose. 

The problem with the strap it on approach to solar charging is that the angle tolerances for panels are very specific and the efficiency sweetspot is rather narrow. Because of how the current lead phones control current, you need a steady shot of sun to get it done, including the important taper off current that completes the charge. Otherwise, the phone dies faster than normal. 

Solar is great for long tours that have rest days built in because then you can spend the day moving the panel around and boosting up. For the short tour, the crop of portable batteries with solar panels built in get the job done better and cheaper for the time investment. I use a Poweradd 10,000 mA battery in my EDC and on the road. It will charge my phone or tablet (LG Gpad) three times before it needs to recharge. It comes with a biner and loop built in to the housing so the battery can hang around and trickle charge in the sun all day (It is not great or ideal, but some is better than none). 

The caveat with these types of batteries besides the weight is the fact that they take forever to charge on the outlet/mains (my poweradd needs 14 hours from empty to full at 5V 1.8A). On the best day of sun with a 7 watt solar that offers an immediate 5A usb conversion, you would need about two days or more to charge your 15000 mA battery from empty, patiently moving the panel each hour to track the sun. If you charge the edge 810 from empty to full on your computer USB, time it and add 90 minutes, you can estimate how long a panel in perfect conditions will take to charge the GPS. Again, solar battery wins for the short term. 

All this said, I'll never part with my panel for long trips or lazy slow paced weekenders. But for a week or less, durable 10000-20000 mAH battery with a trickle solar charger is the best bet for most tech needs. If using Spot and GPS units simultaneously on a 7 to 10 day trip, carry two batteries instead of one huge one because of efficiency losses. For a three to four day brevet, one big durable battery is all you need though AA spare weigh less and can be had if racing in civilitation.


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## Le Duke (Mar 23, 2009)

Probably not an option for most, but something worth checking out is a BioLite stove.

Burn small bits of wood, charge your devices. I've used it backpacking at 9,000-12,000ft in CO, in the snow. Any kind of dry fuel will work, and it doesn't care about the weather.

It will boil 1L of water in well under 10min, while charging a device. And, as long as the initial fuel is dry, can use damp wood, due to the way it works.









Sent from my iPhone using Tapatalk


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## bardynt (Oct 11, 2011)

Le Duke said:


> Probably not an option for most, but something worth checking out is a BioLite stove.
> 
> Burn small bits of wood, charge your devices. I've used it backpacking at 9,000-12,000ft in CO, in the snow. Any kind of dry fuel will work, and it doesn't care about the weather.
> 
> ...


i saw one of these at the shops it was huge compared to other stoves plus then you have to have wood or something to keep it going


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## Le Duke (Mar 23, 2009)

In every place I've ever been, wood is easier to find than any petroleum product. Not too many trees growing cans of white gas or diesel...

The stove packs inside the 1.5L pot, BTW.

Sent from my iPhone using Tapatalk


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## bardynt (Oct 11, 2011)

Le Duke said:


> In every place I've ever been, wood is easier to find than any petroleum product. Not too many trees growing cans of white gas or diesel...
> 
> The stove packs inside the 1.5L pot, BTW.
> 
> Sent from my iPhone using Tapatalk


I know what youre saying but i found compared to any other stove its big

plus having to lift the pan or pot to add more wood to cook isnt ideal

if im going to have a wood fire i will dig a little hole then cook on a fire rather than carry that

i suppose really personal with what you will carry


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## Le Duke (Mar 23, 2009)

You don't lift anything to add wood. You put it in through the exhaust ports. 


Sent from my iPhone using Tapatalk


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## Aushiker (Sep 27, 2007)

bardynt said:


> I know what youre saying but i found compared to any other stove its big


+ 1 ... My preferred choice of pot is under 700 ml and my stove kit is about it all packing up in a small kit.

Each to their own but.

Andrew


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## bardynt (Oct 11, 2011)

Aushiker said:


> + 1 ... My preferred choice of pot is under 700 ml and my stove kit is about it all packing up in a small kit.
> 
> Each to their own but.
> 
> Andrew


The only thing was looking at was solar panel setup

i looked at jaycar for solar panels

you can get ligthweight 120watt panel for about $300

i think with battery and other gear needed cost about $500

The heaviest thing would be the battery but considering that some of the other lightweight solar panels with tiny batteries costing alot more and are only 20 watts or 40 watts.

Im not sure how well it would fit on trailer for touring and if the extra weight could be jusitfied


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## vikb (Sep 7, 2008)

Aushiker said:


> As a guide I am looking at most of the time going five days to seven days between main power sources and I use a Garmin Edge 810 that will be the main item needing charging. I also carry an iPad but that gets limited use and can generally survive this time-frame.
> 
> Ideas? Anyone have other ideas of on off-grid bikepacking without a dynamo?
> 
> ...


The powered items I usually BPack with:

- GPS [2 x AA]
- Digi Cam [ 1 x proprietary LIon]
- headlamp [3 x AAA]
- InReach [internal battery lasts months if just used for emergencies]

Going 7 days without needing to charge isn't too hard. Personally I wouldn't bother with solar, dyno hubs or anything other than carrying a spare set of batteries for the GPS & camera plus their chargers if it's a multi-week trip.

The headlamp gets used sparingly as I see well enough at night in camp not to need it so I put lithium batteries in it and it's good for a month +.

The InReach lasts more than a month used for emergencies and the odd message home.

I find that with judicious power conservation techniques batteries go a lot farther than without. [ie. shutting off GPS at stops, not looking at photos on the camera's LCD at night in camp, etc..]

Ultimately I get far less enjoyment from having gadgets with me on a trip than I do from the simplicity of not having them.


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## Linktung (Oct 22, 2014)

I carry an 8 inch tablet which is an absolute necessity for my trips. I have tried the separated panel and battery approach for recharging and that didn't work so well. The best setup has been the brunton freedom all in one panel and battery. You can recharge with the sun or outlet. The older my tablet gets the more power it consumes. I am always shopping for a rugged, waterproof, 4G tablet with easy read screen, that gets decent battery life. The new fast charging phones look promising and I might break down and get one with an extra large screen.


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## zombinate (Apr 27, 2009)

Might also consider something like the PowerPot, works like the biolite stove, but built into the cookware


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## TitanofChaos (Jun 13, 2011)

I haven't done a ton of multi day trips but I carry an external battery pack

Anker 2nd Gen Astro E3 10000mAh External Battery

I've run my go-pro with this on time lapse mode for 10 hours on one trip

It ran my phone and an external speaker for 8 hours at a cross race this year too

it should charge the garmin 810 to full about 9 times, or my tablet twice

I guess it depends on your garmin settings and how long it's going to run every day

Anker now makes a 25,000mah version, weighs just under 1#, I imagine solar is about the same but more bulky and more likely to get damaged


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## xjcrawlr (Jun 19, 2007)

To get back to the original post...check into SP dynamo hubs, they have a 15mm through-axle hub and there are rumors galore about a 150 O.L.D. conversion for them. Even if not available yet, it would be a very simple matter for a machine shop to fab up a set of spacers to fit this hub to 150. I am using a 9mm QR, SP hub now and loving it.


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## pimpbot (Dec 31, 2003)

bardynt said:


> i saw one of these at the shops it was huge compared to other stoves plus then you have to have wood or something to keep it going


I got one of those BioLite stoves at an REi gear sale for mega cheap. I messed with it to see if it would work for me. I ended up flipping it on craigslist for a tidy profit. 

The main issue with that thing (besides weight) is that you have to empty out the ashes every half hour or so. In that half hour, you're lucky to get 5%-10% gain on the charge of an iPhone. Also, it doesn't kick out enough current to charge an iPad.

BTW, I messed with a couple different brands of these sort of things....









... and they are useless. Like, you leave them in the sun for a FRICKIN' WEEK, and they charge up. Then, you use them to charge your phone... once.... and then wait another FRICKIN' WEEK. They work okay as a battery pack when plugged into a USB port to charge, but don't count on that solar panel actually adding anything useful.

I mean, you really need a solid square foot of solar panel going all day long in direct sunlight to generate enough power to be useful.

Second that, about choosing your gear well. I have a Canon Elph 1300 camera that runs for a good solid month on a charge (like 250+ pics), but my Pentax rugged outdoorsy camera is half dead after a day of shooting... like 30-40 pics. I thought something was wrong with the battery, so I got a brand new extended run battery, and it was no improvement. But hey, two batteries run twice as long, right?

iPhones can run (sleep) a long time if you put them in airplane mode.


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## rallyrcr (May 5, 2010)

I used to turn my phone off to conserve the battery figuring I could turn it on when needed. Found that I was not taking as many pics b/c it was a pita to turn it on and wait the few moments for it to power up, etc. I find airplane mode is almost as good and much easier and quicker to use. 


Sent from my iPad using Tapatalk HD


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## Himself (Oct 11, 2008)

Interesting stuff. I'm doing a 30 day 3,000 k Brevet next year and in leading up,a 400 k randoneur ride in (hopefully)!under 27'hours in a month. My issue is similar, as I run an Edge 1000 plus lights and haven't been able to find a dyno hub yet in New Zealand to have a wheel built up with. Any ideas? Especially for the 400 as it will be my longest continuous ride and I'd love to Strava it for posterity!!


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## mtbbill (Dec 31, 2003)

I'm just getting into bikepacking. I'm looking to use my Goal Zero Nomad 7 panel along with a Guide 10 battery pack and maybe a 4,500mah battery pack as well.

Guide 10 Plus Solar Kit | Complete Solar Kits | Goal Zero

The panel straps nicely to the nice of my backpack vertically and straps to the front of my handlebar bag horizontally easily. I'm planning on putting on either spot depending on my predominate direction of travel will be for the day.


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## TheirOnlyPortrait (Dec 30, 2014)

Hola!

Goal Zero's new toy:
Goal Zero Venture 30 Solar Kit - REI.com

Saludos,
Federico


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## abrooks (Feb 1, 2015)

Looking on Google I found this 
PowerPot Thermoelectric Generator | ThinkGeek

I'm guessing it work on the Seebeck principle.


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## bikeny (Feb 26, 2004)

abrooks said:


> Looking on Google I found this
> PowerPot Thermoelectric Generator | ThinkGeek
> 
> I'm guessing it work on the Seebeck principle.


The Powerpot was already mentioned in post #17.


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## abrooks (Feb 1, 2015)

bikeny said:


> The Powerpot was already mentioned in post #17.


Sorry my bad, I missed it. 
I only mentioned it, as I've seen some reasonable good hacks. Although they are on the large side.


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## crackerdog (Dec 18, 2011)

Seems to me, being an old guy, the best way is to cut down on power use, not to see how to get more power. Some cameras use less power than others. Get a map and learn how to read it to cut down on GPS needs. I don't use GPS so I don't know what I'm missing so I may be wrong on this.


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## Haust (May 22, 2010)

I know that I'm late to the party, but this has me thinking as well. I remembered a gizmo that I saw a while ago and found it again, pretty easily.

Presenting the pee powered battery! Don't laugh. They use just about any liquid, but most of their notoriety comes from the ability to use pee. Water works fine, as well. They've been receiving pretty good reviews and can be found in half a dozen places. About 30 seconds of searching found this site: NoPoPo Eco Water-powered AA Batteries.


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## pimpbot (Dec 31, 2003)

Haust said:


> I know that I'm late to the party, but this has me thinking as well. I remembered a gizmo that I saw a while ago and found it again, pretty easily.
> 
> Presenting the pee powered battery! Don't laugh. They use just about any liquid, but most of their notoriety comes from the ability to use pee. Water works fine, as well. They've been receiving pretty good reviews and can be found in half a dozen places. About 30 seconds of searching found this site: NoPoPo Eco Water-powered AA Batteries.


"

Two sets of three batteries (6 AA batteries in total)
Proprietary NoPoPo hydro-electric battery from Aqua Power Japan
Holds charge up to ten years
Also charges with beer, sake, cola, or even urine
Size: 9.65 x 2.75cm (3.75 x 1.08")
Current: 60mA-300mA
Capacity: 1.6Ah-0.6Ah
Voltage: 1.5V
Can be charged up to five times
Manual: Japanese
"

Can be charged up to 5 times? Does that mean you get 5 uses out of it and they're dead? Doesn't sound very useful to me.

So, where does the water go? Does it react with a catalyst and it kicks out vapors? It sounds not like you're making energy out of water, but energy from a reaction from something inside that gets used up.


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## pimpbot (Dec 31, 2003)

abrooks said:


> Sorry my bad, I missed it.
> I only mentioned it, as I've seen some reasonable good hacks. Although they are on the large side.


... and not terribly effective. If the thing kicked out a solid 2A charge, it would be much more useful.

I did see something interesting recently where a guy hacked a computer fan and some charge regulator circuit into working as a windmill. Not sure how much energy you can extract there, but at least it won't drag you down at low speeds.


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## pimpbot (Dec 31, 2003)

Harold said:


> Solar-only, I'd be real leery about. You would need a rather large bank of cells to get enough juice with the really suboptimal charging you'd get on a mtb. Ideally, the panels would work best if you could be stationary to charge them, so you get them out into the open with an optimal view of the sun. While riding...you can hang panels on a rear rack, on a backpack, that sort of thing...but you'll not be getting the best charge all the time that way.
> 
> Power usage is going to be an important factor, too. How long will your device last on a charge before it needs charged up? A DSLR, I wouldn't be terribly concerned. My Canon battery lasts quite a long time. With a spare or two, you'll get quite a long time without needing to recharge. A fitness GPS that would need a charge every day or two? That's really pushing it. Add a smartphone and its battery needs. Ouch.
> 
> ...


That 16000 mAH battery looks pretty swank. I'll bet you can pack 3 or 4 of those for less weight and less money than a solar kit. I guess if you're wrong about the capacity, you're hosed.

I've had good luck with my $15 5600 mAH battery for overnighters. I was able to charge a nearly dead iPhone 6 (not plus) and my Garmin Edge 705 back to 100% with plenty of juice left over.


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## audios89 (Jul 11, 2015)

I was going to try something like this:
DIY Pedal-Powered Phone Charger for Your Bike « MacGyverisms

Seems slightly ghetto but probably more efficient than solor and sure a hell of a lot cheaper and lighter than anything else suggested.


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## Smithhammer (Jul 18, 2015)

I tend to agree with crackerdog - i try to really minimize carrying things in the backcountry that are dependent on batteries and re-charging. People have been doing lots of great trips in the backcountry for a long, long time before having the array of gadgetry we've convinced ourselves we 'need' any time we set foot outdoors these days. Not telling anyone else what to do here - just encouraging thinking critically about what "need" really means, and the trade-offs that inevitably come with conveniences.

That said, I bought one of these on Amazon last year. As others have noted previously, the solar panel is of marginal benefit, but it charges quickly from a USB and will easily re-charge an iPhone 5s 3-4 times on one charge. Inexpensive and built for reasonable abuse as well.

Amazon.com: Nexcon Solar Panel Charger 5000mAh Rain-resistant Dirt/Shockproof Dual USB Port Portable Charger Backup Power Pack for iPhone 6 plus 5S 5C 5 Samsung Galaxy S6 S5 S4 S3 Note 4 3, All USB Devices, Black: Cell Phones & Accessories


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## Ivan67 (Aug 23, 2013)

I thought about going with some solar my self, I have also looked at the Bio Lite stoves too. I am not a weekend warrior or the every now and then bike camper, I live on my bike and just ride all over Europe and Nortic countries for years now. 

I have a few electronic devices like this laptop with 6 battery's, a satellite phone with 4 batts, GPS, Minelab MD and some lights.

I was not worried about the weight at all, loaded down my rig tugs around 110 kilograms plus my weight.

In the end thought since I have been doing this for over a decade now this way then why would I waste my time and money going solar. Normally by the time I need a charge on something I am out of the bush and staying at a camping site where they have electric. I am rarely ever in the bush longer than 6 weeks at a time.

Six weeks is a long time on a bike in the bush tugging a real load, so I have to make it to a site that I can stay and refit my gear, clean and service everything, get everything charged back up and buy some dry foods. My normal time at a site in the winter is about 8 days, but in summer I am always at a camp site on some beach MDing looking to find some lost coins and jewlery, then I spend it all on new gear that needs to be replaced. 

But I am not saying that I am against it at all. We have 48 people in our group that are retired military just like me that only ride around. Some of them are really into the Gucci Gear hardcore like solar, 3 of them just got them selves the Bio Lite Stoves with the grill attachment. Cool stuff and it works for them. 

There is only one way that I could see needing to purchase something that could charge in the bush and that is going to be when we head down to Australia if our visa's get approved. But in Europe I do not need it because the most commonly used item that sucks the juice is the Minelab CTX 3030, but I have 9 batts for that, but also I know all the hot spots to find gold and to find jewlery and I can plan properly to ensure that I can hit an area clean without worry that I would run out of juice.

But in Australia I do not know if I would be able to find a place as often as I would need it, it is fresh ground for me and prospecting until I get on the gold would take a while I suspect no matter what kind of Geo-Intel I already have.

So that was just my thoughts, if you do not need it then do not get it.


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## Mark_BC (Sep 19, 2012)

I just like to take lots of video and photos so I don't want the batteries to die and I have no way of charging them. Solar is a pain, I think I'd go with a dynamo hub, but then you ahve to ride, which is usually what you are doing bikepacking! Except for rough slogs where you are hike a biking more than riding. In that case a solar panel would be better. I got a marine roll up panel which is pretty good. Not cheap but it does the job.


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## cboyd01 (Dec 1, 2015)

I'm surprised no one has mentioned the PowerMonkey Extreme. Best of solar and a rechargeable battery pack. The panel can be hung on a back pack or something else. The battery pack will charge an iPhone a couple of times.

https://www.powertraveller.com/en/shop/portable-chargers/outdoor-adventure/powermonkey-extreme-12v/

I bought from a U.S. Source, which also included a zipper fold-out pouch designed for soldiers.


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## SVO (May 25, 2005)

IMHO solar panels are to bikepacking as fixies are to hipsters: Presents a desired image rather than being truly practical. Run the numbers on weight and power delivered (never mind bulk)- solar essentially never makes sense unless you are several weeks in the backcountry at a shot- maybe a few locales on earth. Power banks for units that can't take AA or AAA lithiums. My 17kMAH unit weighs 360g.


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## Smithhammer (Jul 18, 2015)

SVO said:


> IMHO solar panels are to bikepacking as fixies are to hipsters: Presents a desired image rather than being truly practical. Run the numbers on weight and power delivered (never mind bulk)- solar essentially never makes sense unless you are several weeks in the backcountry at a shot- maybe a few locales on earth. Power banks for units that can't take AA or AAA lithiums. My 17kMAH unit weighs 360g.


Respectfully, that hasn't been my experience. I have no need to portray an "image" when I'm in the backcountry. I make my choices based on what is simple, cost-effective and works.

Power banks are great if you're only out for a few days, and I've used them extensively, both for work and play. But what happens when your power bank runs out of charges? Then you're just carrying a useless brick around, unless you're doing a route that allows you to find some AC power along the way and charge it up again. Most of my trips don't offer that, hence my choices. YMMV. 

Goal Zero 7 Nomad - great for keeping my iPhone topped up and Gaia running. Depending on the trip, I also carry a small Nexcon power bank. When the phone is fully charged, I can switch the PV module over to charging the Nexcon in case I need to charge the phone in non-daylight hours. For minimal weight/space, I've got active charging power and storage. It's a simple, pretty cheap system that works well, indefinitely.


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## Rob_E (Nov 22, 2010)

Well, it may be a zombie thread, but it does have some good thoughts, so I'll add to it:

I think a cache battery is useful no matter what. When I try to use dynamo or solar power to charge my phone, any fluctuations in power cause the screen to come one. The screen seems to be the biggest drain on the battery, so when my speed, or the sun, is inconsistent, trying to charge the phone can actually make it deplete faster. Better to have a battery as an intermediary, even though an intermediate battery is going to be less efficient.

Haven't tried a solar panel with my bikepacking set up,but I expect that I could drape the panels over the handlebar bag or the seat bag, whichever gets better sun. I did use mine on my rear rack, and I seem to remember it working fine.

If your wheel can't be fitted with a dynamo (and I thought they were making wider dynamo hubs these days, but I can't find one listed), then there's always the sidewall option, the old-style bottle dynamo. I think there are still a couple decent ones on the market. And a bunch of crap ones, so do your research.

I used to think that dynamo would always win over solar, because rain or shine, the bike has to move forward. Now I'm not so sure. I think, as others have noted, that solar can be very effective under the right conditions.

I haven't taken my set-up into the wild for days on end, but I do regularly attend a music festival that involves biking to/from the venue and camping there for 4 nights. Usually I bring a cache battery and try and find an open outlet. They can be hard to come by, and one time I left a battery charging and came back to find it, and my charger, gone. Last fall was the first time I brought a solar panel. I also can charge with my dynamo hub. I also added two extra days of camping on the way there: one at a primitive campsite, and one at an unofficial campsite, which means that by the time I got to the concert, I had already been 3 days and two nights without a place to plug in. But I kept one cache battery plugged into my solar panel whenever the sun was out and one plugged into my dynamo whenever the bike was rolling. That amounted to 4 days when I had dynamo power (although that first day everything was fully charged, so I didn't need it) and three days when I relied upon the sun when it was out, which was maybe half the time. Still, with moderate sun and only half the days having access to dynamo power, that may be the first time I've remained comfortably charged up all weekend and didn't have to track down an elusive, empty, electrical socket. Using solar power turned out to be a pretty good way to grab some power. I'm not going to give up on the dynamo yet, because the sun is not reliable, but I was surprised at how well the solar did.


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