Solar charging 18650 on the AT light weight hiking

Hi everybody....I searched a lot of threads but can't find the exact answer...or at least current information. I'm looking for a light solar charging kit for 18650 batteries. Will be doing section hikes of the Appalachian trail and weight is critical.
Thanks Echo154

Echo, are you planning to do the whole AT in pieces? I've done a few chunks, but always thought about the whole thing... you will probably have to find a system that can be mounted in top of the pack while you're hiking during the day. I'm following the responses... good luck

echo154 said:

Hi everybody....I searched a lot of threads but can't find the exact answer...or at least current information. I'm looking for a light solar charging kit for 18650 batteries.

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For someone with electronic capability, I'd just get the biggest solar panel that you would be happy backpacking with and then I'd get a cradle or something that could hold or connect up to your 18650 battery and directly wire between battery and solar panel without having to use an off the shelf charger or USB interface.

There is just a couple of things you'd have to do to make this work.

Measure the short circuit current of your solar panel so you know what the max charge current will be to your 18650 battery. I'd probably pick a solar panel with max Isc of 1000mA if using a 18650. Place a schottky diode in series between the solar panel and the battery. This will keep the battery from being discharged when the solar panel isn't outputting. Rig yourself up a P-channel mosfet switch controlled via a voltage comparator that is set at a trip point of 4.20v. Even if you have a 12v solar panel that typically has an open circuit voltage around 21v...........that voltage will not harm the battery because it will get sucked down by the load of charging the battery and the comparator will protect the battery from ever going over 4.20v. This method won't exactly be constant current (CC) followed by constant voltage (CV). But it won't hurt the battery either if you know your max charge current (which would be the solar panel Isc) isn't too excessive. Battery won't ever get fully charged because of not having a decaying current while it sits with CV, but it should get 90% or better charged.

Just a thought .

I've only hiked the AT in a few areas [not really hiking, more like a gentle 2-3 hour walk distances and tell my ride to pick me up at so and so.] most of the time you will be under trees. Partial sunlight is not enough to charge anything unless you are packing a solar panel the size of a 2 person tent. I do not recommend hiking at night unless you are trying to get off the mountain in an emergency or making way into [not out of] camp. How much light do you need to run though 18650s? you don't need 1000 lumens to set camp.


Even if you arrive at full sun conditions, orientation is important. Incremental weather, including fog, impedes performance. There's four kinds of weather in the mountains that I know of: too hot, too cold, too wet, rain. You can count on great weather but not for long. If it was me I would stick to lights that uses disposable batteries so I don't have to take it apart to charge, preferably ones with firefly modes that eliminates glare and maximizes your run time.


I'm an amateur astronomer, places I go to requires 20 minutes of pupil dilation to identify objects in the terrain, By that time the sky really opens up. Even with the dimmest of red lights at my disposal I drew most of my sketches with a minimag running on eneloops with a red balloon stretched over it. 25 lumens is TOO BRIGHT under those circumstances. Up there on the AT, it will probably be about as much. You really only need light to set up camp, don't leave it on for too long or you'll find bugs everywhere.


18650 batteries by itself isn't designed for the elements... in fact the containment cylinder is steel and will rust if you leave it out long enough. If you really must go with the solar route and using 18650s for something else, I would recommend investing in a 18650 flashlight with a built in charger and removable batteries and then buying a USB solar charger instead. There seems to be quite an extensive collection of products in that category and the combination is cost effective.


For me, I would go for a CL25R because its a lantern, built in charger, removable 18650, Six modes with a favorite being the moonlight mode.
Reviews:
http://www.candlepowerforums.com/vb/showthread.php?405953-Fenix-CL25R-lantern-review-with-field-test
http://www.candlepowerforums.com/vb/showthread.php?423156-Fenix-CL25R-amp-CL30R-comparison-review
http://www.candlepowerforums.com/vb...A-White-Red-leds-micro-usb-350-lumens)-Review


For the solar panel I would go for a GRDE 24W Folding Solar, its got a large velcro pocket where the ports are, so its fairly splash proof. Without a lantern you can concievably stuff an Olight UC charger
https://www.amazon.com/dp/B01K1QFDDG/?tag=cpf0b6-20
http://www.candlepowerforums.com/vb...UC-(Universal-Charger)-Magnetic-amp-USB-input


Why 24W when charging a battery needs only 3W? Again, incremental weather. You cannot count on a 5W panel delivering 5W when its a hazy day. When you're on the trail you don't have time to wait for the sun to come out. Charging on the move requires oversizing the panels and derating the output. But again, personal opinion. I'm interested to hear from other inputs.

The burning question is - are you going North to South or South to North. It makes a difference because with South to North if you have the solar panel fastened to your backpack you will be getting at least some direct rays onto the solar panel. In the other direction, for the most part you will only be getting incident light, not direct ways, which means much reduced output if any at all.

Anker makes a couple of nice portable panels in the 15-21 watt range. But be careful - they are using solar panel output to make that claim, and that is not what will be available at the USB port(s). Look at the fine print for the total amps available at the USB port(s), multiply that by 5, and you will have a much better idea of what you can expect for output.

Personally, I would stick with the solar to power bank, power bank to charger route. The reason being that as you move about, even in direct bright sunlight, the output of the solar panel will vary based on its orientation at that moment. I haven't read any reviews that discuss how a given charger will work with a constantly varying current input. I think using a power bank would tend to negate that kind of problem, although I have to admit I don't know if any power bank, since it is in effect a charger, will handle varying input current either. I would recommend contacting the manufacturer of whatever charger/power bank looks good to you and ask them that question. It might save you from some severe disappointment down the road. I do know that my Maxboost 15000mAh power bank didn't seem to have any problem handling varying input current when I was testing my solar setup.

Good luck and enjoy your trip. Let us know how what you select for your journey, and how well it performed for you.

PS: I would suggest getting a small AA or AAA light as a backup in case of prolonged lack of sunlight, or if something happens to your normal setup. I know there will be stores along the way, so you should be able to pick up more lithium primary AA or AAA cells if needed. I say lithium primary because they are lighter in weight than alkalines, and last longer in use. A Streamlight Microstream or a Lumintop Tool or its Manker equivalents would be ideal, and not very expensive. A Nitecore LA10 CRI would also work, and would make a great tent/camp light as well. When it is fully retracted it puts out a nice soft flood of light that should work very well for any night time wandering.

echo154 said:

Hi everybody....I searched a lot of threads but can't find the exact answer...or at least current information. I'm looking for a light solar charging kit for 18650 batteries. Will be doing section hikes of the Appalachian trail and weight is critical.
Thanks Echo154

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Figure out how much light you'll be needing over the X amount of days that you'll be gone at a stretch. It might just be lighter and easier to carry say 8 ~50gm precharged 18650s in plastic cases and go that route.

Two of my LG D1 18650s weigh 47.1gm each, for a total of about 3.3oz., so you're looking at ~13.2oz. for eight of them. That might be a lot less than a folding panel, charger--even something like a Xtar MC1+ ANT and cable.

You can get a Tomo V8-4 plastic 4x18650 powerbank and use the cells in that, if you have other devices that need to be charged up while you're on the AT.

Like Illum states, you're not going to get a lot of direct sunlight while you're hiking during the day. If you were in the desert, or on a mountain top, sure, but you're hiking through tree canopies and whatnot.

Best to just bring spares once you figure out what you'll be needing in terms of power.

Chris

Woods Walker has had several good threads on solar charging and power solutions for backpackers. These should give you some ideas.

Bob

http://www.candlepowerforums.com/vb/showthread.php?419997-Nitecore-F1-Flexible-Charger-Review-Field-tested!&highlight=Solar+charging


http://www.candlepowerforums.com/vb...woods-power-solution&highlight=Solar+charging


http://www.candlepowerforums.com/vb...e-night-backpack-jog&highlight=Solar+charging

This flashlight was born of the Appalachian Trail

http://9voltlight.com/

The one lithium primary 9 volt battery I had was not impressive. A full 9 volt alkaline will last a long time, even with the 2 white emitters, when used prudently. Not sure what you are wanting the 18650 for; please tell us. You could get a decent, powerful flashlight that can use lithium primary AA's (or alkaline AA's in a pinch). I have, and appreciate, a ~5 watt and a 15 watt solar panel as well as a stationary PV system. Devoting that much weight to any charging system that may not give you the returns you hoped, unless you are inclined to experiment, or have some other reason, seems an error to some of us. When the weather turns, a seemingly simple error can get very, very serious.

Great Luck to You, and please let us learn from your decisions, and touch base with us when you can.

Paklite is not that good of an idea.... from the standpoint of output it is, but the contacts does rust... rather quickly too.

I own a Super, high/low. Loved the thing to death. Left outdoors and it rusted quick! Its a nice backup light, but not a primary. Also a headlight can be a flashlight, but a flashlight can't be a headlight. Pak-lites have that problem. Even with the strap they sell, its a lousy headlamp.

Groo here
A very low power [candle etc] light that uses Zinter [AA or AAA ] rechargable and a Coghlans 6000 mAh Power Pack etc as a charger.
Small light most of the time, a bigger one for "in case"
Solar panel for top off, hand crank for "POWER"

Illum said:

Paklite is not that good of an idea.... from the standpoint of output it is, but the contacts does rust... rather quickly too.

I own a Super, high/low. Loved the thing to death. Left outdoors and it rusted quick! Its a nice backup light, but not a primary. Also a headlight can be a flashlight, but a flashlight can't be a headlight. Pak-lites have that problem. Even with the strap they sell, its a lousy headlamp.

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Good to know. The tint leaves some of us rather cold as well. We use one at bedside, but rusting in the field; not acceptable.

It would be nice to get some feedback from echo154.

KITROBASKIN said:

The one lithium primary 9 volt battery I had was not impressive. A full 9 volt alkaline will last a long time, even with the 2 white emitters, when used prudently. Not sure what you are wanting the 18650 for; please tell us. You could get a decent, powerful flashlight that can use lithium primary AA's (or alkaline AA's in a pinch).

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Even if solar charging may not be as feasible on the AT as it is on the PCT, going 18650 has one HUGE advantage over going with 9V or AA/AAA. Simply put, if you want the lightest weight form factor for the amount of energy stored, there isn't anything better. So evenif you have no intentions of ever charging out in the wilderness, carrying pre-charged 18650s is going to beat 9V and AA/AAA by a long shot when it comes to lumen-hours per pound.

Of course, there's always going to be someone who brings forth the argument that you simply don't need lots of lumen-hours, and that you can make due with a 25 lumen light that can run ages on a single AA. This is, of course, an option. And in the end, it is really no different from the old days, when a ~25 lumen light was about all we could hope for in any size. But whether or not this is what you WANT is another matter. You could certainly forgo LOTS of things while backpacking and save LOTS of weight in the process. Why carry a tent when you can sleep under the stars? Why carry a stove and cookware when cold meals will keep you alive just fine? Mattress pad? Sleep on the hard ground like a man! But whether you would want to give up this, that, and the other thing just because someone else says you can (and should) is another matter. Only YOU can decide what best fits your wants and needs.

If weight is critical, there are 1 watt, 27g flexible cigs panels on Amazon and eBay that are 4"x8", they advertise being 6 volts, so that should be 165 mA in direct sunlight. 3 of them wired inn parallel would weigh 3 oz and deliver nearly 500 mA in direct sunlight, which is comparable to the old USB standard, before 1 and 2+ amp chargers became common.
Would a Nitecore single 18650 charger run on them?
Otherwise you'd have to cobble together a trickle charger, there are lots of +/- 5$ USB charger circuit boards online as well.

Also, at 5.5oz there's this: https://www.amazon.com/dp/B0091PU5TG/?tag=cpf0b6-20

I like the idea of opportunistically charging a spare 18650 while hiking, and the panels I was mentioning are the direction I'm heading, but for light weight and less hassle it may be that an AA powered light and some lithium AAs would suit your needs better.

eh4 said:

I like the idea of opportunistically charging a spare 18650 while hiking, and the panels I was mentioning are the direction I'm heading, but for light weight and less hassle it may be that an AA powered light and some lithium AAs would suit your needs better.

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For the ensuing Zombie Apocalypse, I'd want all of this stuff, but for say a 7 day hike though the AT and carrying only a single flashlight to save on weight, I'm probably going to forgo the solar charger, li-ion charger, cable and just bring spares.

I think that it just comes down to practicality: weight penalty vs. sufficient stores and needs. Say 8 hours a night on medium times 7 nights, equals 56 hours total, with a buffer zone of 20% added onto that, so one might need ~75 hours of medium light from a particular light? Think of things in that light (pun intended!)

Energizer Lithium AAs weigh half the amount as their alkaline brothers, at about 15gm ea., so that might be a good way to go, but at ~47gm, a quality hi-cap 18650 holds about 3 times the amount of energy as an Energizer Ultimate AA, so as was stated above by Matt, that just might be the better and more efficient play.

Chris

StorminMatt said:

Even if solar charging may not be as feasible on the AT as it is on the PCT, going 18650 has one HUGE advantage over going with 9V or AA/AAA. Simply put, if you want the lightest weight form factor for the amount of energy stored, there isn't anything better. So evenif you have no intentions of ever charging out in the wilderness, carrying pre-charged 18650s is going to beat 9V and AA/AAA by a long shot when it comes to lumen-hours per pound.

Of course, there's always going to be someone who brings forth the argument that you simply don't need lots of lumen-hours, and that you can make due with a 25 lumen light that can run ages on a single AA. This is, of course, an option. And in the end, it is really no different from the old days, when a ~25 lumen light was about all we could hope for in any size. But whether or not this is what you WANT is another matter. You could certainly forgo LOTS of things while backpacking and save LOTS of weight in the process. Why carry a tent when you can sleep under the stars? Why carry a stove and cookware when cold meals will keep you alive just fine? Mattress pad? Sleep on the hard ground like a man! But whether you would want to give up this, that, and the other thing just because someone else says you can (and should) is another matter. Only YOU can decide what best fits your wants and needs.

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Good Points, and also understanding that those of us who frequent this forum are very-into having portable illumination capability, it is worth it to carry some horsepower for photon generation. What about those cookstoves that also generate electricity? Would some kind of crank device be a way to charge an 18650? Some of us would not like to carry Li-ion without some ability to charge. As technology advances, wearing clothes that make electricity (there are already backpacks with an integrated solar panel) or using the kinetic energy from the act of walking, perhaps there will be a more attractive option for rechargeables on the AT.

KITROBASKIN said:

Good Points, and also understanding that those of us who frequent this forum are very-into having portable illumination capability, it is worth it to carry some horsepower for photon generation. What about those cookstoves that also generate electricity? Would some kind of crank device be a way to charge an 18650? Some of us would not like to carry Li-ion without some ability to charge. As technology advances, wearing clothes that make electricity (there are already backpacks with an integrated solar panel) or using the kinetic energy from the act of walking, perhaps there will be a more attractive option for rechargeables on the AT.

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I was looking at the BioLite stoves way back at their inception. The new model claims a 2600mAh cell with 3w peak from the heat conversion. It states it outputs 5v and 2A, for 10w, but with the boost inefficiencies, you're not getting much.

Sure, it's better than nothing, but you need 20 minutes of X, Y, or Z fuel to get any meaningful charge back into the mother cell and it's a bit bulkier than any of the flat, foldable stoves on the market, so ehhh? It also has a fixed li-ion cell, so when that goes, you're in trouble.

At some point, carrying all of this gear is going to start adding up in weight and that's not a problem for me. All of my emergency stuff and I now have a lot of it, is meant for car camping, not ultra light backpacking.

I'm still going to state that spare high cap naked 18650s are the way to go on the trail, but you have to put some thought into estimating your realistic needs, otherwise you might end up using very low modes, or none at all.

Chris

Well put Chris love reading your posts[emoji106]

Offgridled said:

Well put Chris love reading your posts[emoji106]

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Thanks. I try and be entertaining, although it doesn't always work out.

I'm just a city slicker hack and the last 'hike' I did was up in Estes Park last summer (Dream, Nymph, Emerald lake trail for sissies) and there were 80 year old grannies hauling *** past my GF and I.

We did see one guy who was fishing in Nymph lake using a Pocket Rocket type stove and some Mountain House, but we just carried a bottle of water and that was it!

I put together my car camping stuff almost 5 years back, so I read up a lot on these things, even though I haven't had to use them all that much in practice.

I mean, if my life depends on it, I don't believe in skimping, but there are a lot of gimmicky things out there and many of them are quite spendy. My last camping purchases were a STERNO Inferno convection pot for $25 and a Swedish Trangia spirit stove, which can be used with the Inferno. Very efficient for $40 vs. the Bio-Lite for ~$130. Four spare NCR-B cells are $20 along with a Liitokala 100 charger/power bank for $4, gets you up to ~$65 and weighs very little in the overall scheme of things.

Now, if I win the PowerBall tonight, then all bets are off. I'm going to hire you guys to carry all of my new, superfluous stuff on my next hike up to Golden Coral.

Chris