### Author Topic: Solar Paper, the world's thinnest and lightest solar charger  (Read 7071 times)

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#### edy

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##### Solar Paper, the world's thinnest and lightest solar charger
« on: July 26, 2015, 03:35:16 am »
I came across this interesting KickStarter campaign. I wonder if anyone can verify if the output is what is claimed.

https://www.kickstarter.com/projects/1398120161/solar-paper-the-worlds-thinnest-and-lightest-solar

They claim in bright sunlight (on the equator at high-noon?) it will charge an iPhone 6 in about the same time as a plugged-in supply. Really?

Here is the amp output shown in one of their screenshots...

My phone can't charge unless it sees at least consistent >1 A or 1.25 A. If I use a 750 mA rated charger it refuses to charge. And it takes 2 hours to charge using a 2 A source. This just looks too incredible to believe.

I can see it helping to reduce the drain on the battery, maybe prolonging the battery life on your phone. Any thoughts?
« Last Edit: July 26, 2015, 03:38:58 am by edy »
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#### tom66

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##### Re: Solar Paper, the world's thinnest and lightest solar charger
« Reply #1 on: July 26, 2015, 04:16:21 am »
iPhone 6 (non-plus) battery capacity 1810mAh @ 3.8V = 6.87Wh
Solar surface area ~2 iPhone 6 = 2 x 67mm x 138mm = solar area of ~0.018m^2
Earth peak insolation = ~1400W/m^2
This will generate 25.2W with a 100% efficient solar panel
Assuming a 20% efficiency panel gives 5.04W (i.e 5V @ 1A)

With no charging losses, phone can be charged in 1.3 hours.
Their claim of 2.5 hours may assume a lower efficiency panel or average vs peak insolation.

The Apple charger is 2.1A, iirc, so this is about half the rate of the Apple charger. Still not too bad.
« Last Edit: July 26, 2015, 04:18:17 am by tom66 »

#### electr_peter

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##### Re: Solar Paper, the world's thinnest and lightest solar charger
« Reply #2 on: July 26, 2015, 04:19:06 am »
KS campaign claims 2.5 W per single panel - this is believable under ideal sunny conditions. However, even if it works, sky will turn dark from you crying massive tears because of the price tag.

#### edy

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##### Re: Solar Paper, the world's thinnest and lightest solar charger
« Reply #3 on: July 26, 2015, 04:21:07 am »
I also found this at my local Home Depot:

http://www.homedepot.ca/product/gocharger-10-watt-portable-folding-monocrystalline-solar-panel-with-2-amp-usb-output/1002707?eid=PS_GO_140203__ALL_PLA-1002707&pid=1002707&kpid=1002707&gclid=COSem_7w9sYCFQIIaQodWdIGlQ

I know it's much bigger, but it produces 10 W or 2 A through a USB 5V charge for $99. Here's another similar folding charger from Amazon: http://www.amazon.ca/ALLPOWERS-Charger-Technology-Portable-Battery/dp/B00MVM2CHE/ref=sr_1_2/190-4986111-6852467?ie=UTF8&qid=1437848072&sr=8-2&keywords=solar+charger+12v It's on sale for ~$66 Canadian. Says it is 14 W, but I'm not sure if you can use the full power as there are various voltage levels it allows you to get for charging phones (5V), car battery (12V) or laptop (19-21V) and I don't know whether this is achieved from separate panels or together and if they are reconfigurable.

The "Solar Paper" is $69 and$79 (all gone) for 5 WATT options, and starts at $99 and$109 for 7.5 W (all gone) and $129 and$139 for 10 W options (all gone). I'm not sure if the value proposition is there, except only for the smaller size... But I can't see it being useful except in perhaps the most limited situations and climates.

Certainly not something I can rely on daily. It is good for camping maybe when your battery pack runs out and you can charge those with it and your phone. But for short trips and the daily commute to keep you going the full 18 hours the battery pack is still a better option. How often is that going to happen? And you could probably buy and charge up a few battery packs anyways. I just see limited use for the average person, but nice to know it's possible.
« Last Edit: July 26, 2015, 04:24:53 am by edy »
"Ye cannae change the laws of physics, captain" - Scotty

#### amyk

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##### Re: Solar Paper, the world's thinnest and lightest solar charger
« Reply #4 on: July 26, 2015, 10:01:57 pm »
More like the world's thinnest and lightest and most fragile solar charger... those PV panels don't look flexible to me.

Does anyone else notice something amiss here?

Quote
Embedded magnets let you easily add or subtract Solar Paper’s solar panels.

Quote
Use Solar Paper's embedded magnets to attach it to metal surfaces.

#### hayatepilot

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##### Re: Solar Paper, the world's thinnest and lightest solar charger
« Reply #5 on: July 28, 2015, 04:16:06 am »
Quote
Use Solar Paper's embedded magnets to attach it to metal surfaces.

This would probably only work on painted or coated metal surfaces otherwise you would short the output.
Maybe the panels come with some sort of isolator clip-on thingy to use with bare metal surfaces...

I don't see a scam here. Over advertised and hyped? Sure but that is nothing false or new. Take those TV infomercials for example, much worse in my opinion.
Theyr claims seem reasonable as others have shown above. If they claimed you could jumpstart a car with it, THAT would be a scam.
« Last Edit: November 05, 2015, 09:01:24 pm by EEVblog »

#### sunnyhighway

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##### Re: Solar Paper, the world's thinnest and lightest solar charger
« Reply #6 on: July 28, 2015, 02:56:34 pm »
You could jumpstart a car with it*

Does not have to be a scam if this was claimed.
Just a common advertising trick would solve that problem.

* Requires 5000 units and our proprietary Y-array cable also available at our store

#### miguelvp

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##### Re: Solar Paper, the world's thinnest and lightest solar charger
« Reply #7 on: July 29, 2015, 02:17:50 am »
I don't see a scam here. Over advertised and hyped? Sure but that is nothing false or new. Take those TV infomercials for example, much worse in my opinion.
Theyr claims seem reasonable as others have shown above. If they claimed you could jumpstart a car with it, THAT would be a scam.

I guess standards are different in Europe. Generally companies are not allowed to make claims that are not demonstrably true. Obviously there are exceptions for clearly ridiculous claims like "cheapest anywhere", but the specific claims they are making would be illegal.

Also, reselling goods is against Kickstarter rules. I'd say it's 50/50 if it turns out they are doing that.

So you are just taking a wild guess and you think the odds are 50/50 that you are right?
It's not their first campaign:

Also what are the bullshit claim? are you doubting they can make a 2.5W panel that is  9 cm x 19 cm?

pledged of $50,000 goal Yes, that is 2000% funded!!! YouTube: www.devhackmod.com "Ye cannae change the laws of physics, captain" - Scotty #### Psi • Super Contributor • Posts: 7013 • Country: ##### Re: Solar Paper, the world's thinnest and lightest solar charger « Reply #16 on: August 30, 2015, 02:34:25 pm » The most efficient solar cells that are not stupidly expensive (that i know of) are the sunpower cells at 22.5%. They're 125x125mm and rated at 0.6V at 6A, cost is around$4 each.
My testing shows they have a real world output of 0.55V at 5A in direct midday New Zealand sun.

So for 5V usb power that's max 0.55A output current. (Assuming you had a 100% efficient conversion or a multi cell setup of the same size.)

So i call this product fake, it would need a cell around the size 250x125mm to recharge a phone at 1A 5V under full sun.
And its barely half that.  So 500mA is all i'd expect form that thing, assuming it's using really good panels.

Edit: Actually it looks like they have a double size version, so that version should get to 5V 1A in peak sun

Things will really start to get interesting if anyone cracks affordable 40% efficient solar panels.
It would make solar powered UAVs totally feasible. You can build them now but they have to be ~1m x 1m wide and very light. At that size/weight its really hard to get control due to wind catching the large surface and throwing it around.
« Last Edit: August 30, 2015, 02:47:30 pm by Psi »
Greek letter 'Psi' (not Pounds per Square Inch)

#### suicidaleggroll

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##### Re: Solar Paper, the world's thinnest and lightest solar charger
« Reply #17 on: September 01, 2015, 01:22:25 am »
Edit: Actually it looks like they have a double size version, so that version should get to 5V 1A in peak sun

"double size" is the standard size.  From the campaign:
Quote
As part of this campaign, we’re offering 5 watt, 7.5 watt and 10 watt chargers, with 2, 3 or 4 panels, respectively.

So they're claiming that each ~180x90mm panel can do 2.5W, which doesn't sound unreasonable at all.  That's ~4% larger than your example panels you brought up, and they're claiming 9% less power from it than what you measured.
« Last Edit: September 01, 2015, 01:27:27 am by suicidaleggroll »

#### edy

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##### Re: Solar Paper, the world's thinnest and lightest solar charger
« Reply #18 on: September 05, 2015, 12:19:09 pm »
In a related Kickstarter campaign, here is another Solar Charger rated at 5W which also claims to be the most efficient cell yet it looks MUCH LARGER in surface area....

https://www.kickstarter.com/projects/sunnybag/sunnybag-powertab-worlds-most-effective-solar-char/description

It houses a 6000 mAh battery. Look what the campaign description says about the 18650 battery.....

« Last Edit: September 05, 2015, 12:21:18 pm by edy »