Deconstructed Solar Panel

[Ryan H.]

I just broke down this solar panel to try to get its weight a bit lower. Not bad results IMO. Starting weight was 13.5 oz and final weight is about 7 oz. This is a 14 watt panel so it has decent charging rates for phones, etc.

http://www.amazon.com/gp/product/B00M16KLM8/

I was hoping to break it down further but the cells appear to be encapsulated in silicone. I'll probably trim a little bit more off the sides, but I think I'm pretty close to being done. To finish it off I'll probably make a hinge in the center out of cuben and then use cuben tape to tape down and protect the wires and contacts.

[todd]

Impressive weight reduction!

[Jennifer W]

Nice work, nice project!

[Richard MINORINI]

Do it right; one shot. I bet the mfg wouldn't warranty it. Just a thought as it could be a costly mistake.

[Bradley Danyluk]

I bought the Eceen 13watt panel which appears to use the same semi-rigid panels as yours. I did the same mod and also got to 7oz.
The cool thing about these panels is thy don't appear to need to be mounted in anything – the panels by themselves are strong enough. I used a hole punch to put a hole in each corner of each panel and clip them to each other with mitten hooks, and can hang the whole thing with some light cord.
The Eceen's USB output came encased in a small plastic box so I just glued that box to the back of one of the panels and it is self-contained.
I made the other panel removeable by putting a mini fan connector on the wire between them. They are wired in parallel – so if you only need one because you have good sun and aren't charging much, the other can stay home.

[Ryan H.]

Agreed about not needing to be mounted on anything. These things are plenty strong on their own.

Cool idea about punching holes in the corners for being able to secure to something.

Also, creative to use the mini-connector to allow for easily removing one of the panels. I tested the model I have and it's running in a series (not parallel). The open voltage is around 7.4 volts which gets stepped down to 5v through a step down module. So anyway, I guess not possible for me to separate mine unless I want to supply a new step-up module.

Agreed about wattage ratings being really optimistic. Manufacturers are really misleading about these things. My panel claims 14 watts because each of the sun power cells it uses can produce 3.5 watts of power (3.5 watts x 4 cells = 14 watts). Unfortunately, when the panel is actually under a load and power is going through the voltage controller, the end result is way, way less output. The most I've ever seen my panel output is around 4.5 watts. For comparison, an iPhone wall charger outputs 5 watts. So when in full sun, a 14 watt panel can almost match a wall charger which is pretty cool.

My understanding is that step down modules are slightly more efficiient than step up modules. I guess it takes the module less work to drop voltage than to ramp it up. At any rate though, I've tested numerous solar panels and have never found any that charge well (if at all) in overcast/shade. Often times if you're in the shade with a panel, the voltage will still be quite high, so an indicator light may illuminate on your panel; But without direct sunlight, there will be virtually no current flowing through the panel and thus no power. I done a bit of testing with my panels and have found that if I hold the panel in direct light on a nice sunny day, I may get around 80-90% power output. Then if I move the panel over a few feet into the shade, the power output drops to 1-3%. So technically they are still producing power, but at the rate it would take a full week to charge my phone : (

I'm still a big fan of solar panels though – especially for summer trips when sun is likely to shine.

[Bob Gross]

Now all you guys need is a tracking mount. This is the mounting bracket that causes the solar panel to pivot and tilt to match the peak of sunlight.

–B.G.–

[Ryan H.]

I'm planning on working on a tracking mount soon. I just need to finish my portable perpetual motion machine first though.

[Paul Mankowski]

The only thing that I would add is to remove that tape and see if there are any exposed solder joints or holes large enough for moisture to get in. If so, put a dab of epoxy over the solder joint/hole in order to prevent corrosion from building up, moisture from getting in, or weakening the wire.
You could even add a dab to that control board so that it isn't flapping around as well. I guarantee that those wires/joints wont last long in a backpack without some support.

[Ryan H.]

Good idea to use an epoxy. That's probably a little safer than just taping it. Thanks!

[Prejoyful]

How does this compare for usability, durability, and functionality to the self-made one you described here: https://backpackinglight.com/forums/topic/103211/  ? I have an EECeen panel, and could easily strip it down like this, but wondered if I should take on the task of making my own as you did.

 

I typically have used my panels on top of my pack, charging an external battery, then charging phone, camera, kindle from that battery at night. Since my battery pack is 10000 mAh, it’s not a very light solution, though, so I was thinking about ways to lighten the panel, and use something more like a 5000 mAh battery, which could carry me through a cloudy day or two on long trips.

[Les Waddel]

I have the same panel as Ryan.  It seems to work pretty good!  Better than others I have tried.  But… my iPhone stops charging soon as it goes out of direct sun and I have to restart it when back in the sun.  My Pocket Juice external battery will continually charge in and out of the sun.  So…my only option is to bring the battery and charge the phone at night.  Extra weight but it works.

Les

[Jason Spangler]

Very cool – was thinking of something like this myself but glad to find others have already succeeded!

I’ve also been worried about the minimum voltage to trigger phone charging – since we are carrying around a phone with a battery, we theoretically shouldn’t have to carry around another extra battery as an intermediate for charging.  I wonder if a supercapacitor could allow charging in bursts after storing enough energy to meet the minimum phone charging voltage for a while – if lighter weight than a small battery,

Anyone try any flexible thin film solar cells?  They are usually less efficient but seem lighter weight and more flexible.  I wonder if part of a pack could be made out of thin film solar cells.

[Author]

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