Any good outdoor weatherproof solar power packs available yet?

BraveSirRobbin said:
FYI, found THIS while browsing for some electronic parts today...
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Thanks for your post!  That's a good find, especially for replacing the solar modules on garden lights.  Thanks to your link I just ordered some today as a near-term fix for exactly that purpose.  
 
I finally did locate an  inexpensive (~$3)  and tiny (60mm square) solar panel with a glass front:   http://www.bgmicro.com/PWR1241.aspx
The existence of its glass front was identified here:  http://www.evilmadscientist.com/2008/simple-solar-circuits/  Allegedly such a mini panel should last forever, unlike 99.999% of panels that size which will eventually fog over from UV damage to a plastic or epoxy front.  
 
By the way, I've since read that some people use Aerospace 303 to protect new garden solar panels against subsequent UV damage.  Not sure how long it lasts.  Still others advocate using a headlight UV clearcoat as a different way to protect new garden light UV panels.  I've also read some claims that the UV damage (after it occurs) is primarily at the surface and can buffed out back to clear again using a headlight rubbing compound.  Anyone here tried one of those or similar methods?  If it's a once-a-year thing, as perhaps the buffing is, maybe it wouldn't be an entirely bad option.
 
The theory makes sense - just like those "Car headlight repair kits" that buff out the oxidation.
 
That 303 protectant is good stuff - out here in the blazing CA sun it can keep all kinds of things from showing sun discoloration.
 
Work2Play said:
The theory makes sense - just like those "Car headlight repair kits" that buff out the oxidation.
 
That 303 protectant is good stuff - out here in the blazing CA sun it can keep all kinds of things from showing sun discoloration.
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I hadn't previously heard about 303, but I notice it does get highly positive reviews.  How long would it typically last in this type of application (an outdoor garden light solar panel) before it needs to be re-applied?  If it were as simple as "once and done" or even once a year I would  try it on the new replacements when they arrive.  If it were once a month, they just wouldn't be worth the long-term effort.
 
That's such a hard thing to measure - we used to use it on the boat and other sun-drenched items.  I think 2-3 times/year is sufficient although if the item gets hit daily by sprinklers that may reduce it considerably.  With something like a boat, if you strip everything off with cleaners, then you reapply the protectant afterwards.  If it's just a solar panel, I'd probably do it like twice/year.
 
Work2Play said:
That's such a hard thing to measure - we used to use it on the boat and other sun-drenched items.  I think 2-3 times/year is sufficient although if the item gets hit daily by sprinklers that may reduce it considerably.  With something like a boat, if you strip everything off with cleaners, then you reapply the protectant afterwards.  If it's just a solar panel, I'd probably do it like twice/year.
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Thanks!  I can live with twice a year.  Then I'll just remember to do it whenever I replace our RO water filters, which is also twice a year.  Assuming it's not a dust magnet, I'll give it a try.  
 
On second thought, some kind of UV filter would be certain to last, if I can get it in a small enough quantity.  Here's a type of plexiglass that blocks 98% of UV:  http://www.eplastics.com/Plexiglass_Acrylic_Sheet_UV_Filter
According to the link, even regular glass will block 90% of UV.
 
If there were a window film that blocked only UV but little if any visible light, that would probably be ideal.
 
I notice there are some automotive clear coats that are highly UV resistant and are alleged not to yellow, but it's not obvious whether they actually block UV or whether they just aren't affected by it.  
 
Just be careful you are not blocking any 'efficient' light with the type of solar panel you are using.  Though most current panels can not 'use' the infrared or ultraviolet spectrum for conversion of (sun) light into energy, there are some newer technologies in development (don't know how current this will be) that will use the entire sunlight spectrum.  After all, the spectrum of the majority of sunlight is either ultraviolet or infrared (so perusing this technology makes a lot of sense).
 
BraveSirRobbin said:
Just be careful you are not blocking any 'efficient' light with the type of solar panel you are using.  Though most current panels can not 'use' the infrared or ultraviolet spectrum for conversion of (sun) light into energy, there are some newer technologies in development (don't know how current this will be) that will use the entire sunlight spectrum.  After all, the spectrum of the majority of sunlight is either ultraviolet or infrared (so perusing this technology makes a lot of sense).
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Thanks for your post.  That's interesting info which I hadn't heard before.  
 
I found this window film which claims to be untinted and yet still block 99% of the UV:  http://www.amazon.com/Clear-Protection-Window-Film-Wide/dp/B004JAW3KW  It does say not to apply it to a plastic surface, which I would be doing, and I wish I knew why it said that.  I'm guessing the reason is because it's co-efficient of thermal expansion is probably different and would potentially visibly warp a plastic window if spread all over just one side of the window.  If that's the reason, then I don't really have that concern regarding the small replacement solar garden panels, which are thicker and sturdier than thin plastic window pane.  Of greater concern is how the film would react to rain, and whether heavy moisture can get under it, as I presume it's intended to be installed indoors rather than out.  If that happens, I'll need to glue it into position around the entire perimeter.  So, it's not by any means a sure thing, but if it works I'll have more than enough left-over to use on other inexpensive panels in the future.  Certainly if it reduces visible light transmission, I'll have to return it.
 
I received the garden light solar panels yesterday.  I'm charging one up outdoors today to see how well it works.  Being low cost, I rather doubt these particular garden light solar panels convert UV into electricity, but I suppose I could check before-and-after the film on one of them with a volt meter.  Also, I have an Oregon Scientific UV weather sensor, so as a performance check if I hold the film in front of it, it's measurement should go to nearly zero.
 
BraveSirRobbin said:
FYI, found THIS while browsing for some electronic parts today...
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Caveat Emptor.  I've tested two of these now, and neither one performs as advertised.  It's supposed to output 3.5 volts when it's dark, but the most it put out in my testing is 1.3 volts, and it outputs that regardless of whether it's light or dark out.  If I remove the battery, its solar panel will output a maximum of 2.3 volts in direct sunlight.  I tried charging its battery on a battery charger and reinserting it, but I still get at most 1.3 volts from it.  I even tried inserting a fully charged known good Nimh battery, and still the best it can do is 1.3 volts.
 
I ran across some battery info relevant to solar that's worth passing along, so here it is:
 
Lithium Titanate batteries:  http://www.batteryspace.com/Lithium-Titanate-Battery.aspx
These are expected to have > 3,000 to 7,000 charge cycles.  According to one of the manufacturers (http://www.aertc.org/conference2010/speakers/AEC%202010%20Session%204/4F%20ESO%20Bat.%20Chem.%20&%20Mat.%20I/Robert%20Misback/Large%20Format%20Li4Ti5O12%20Lithium-Ion%20BatteriesSECURED.pdf), they're expected to have over a million cycles if the depth of discharge is low.
 
So, if you pair those batteries with a glass solar panel in a proper design, it seems the combo should be good practically forever.
 
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