Solar Paper, the world's thinnest and lightest solar charger - Page 1
Forum section: electronics / general

author: edy
author_rank: Super Contributor
timestamp: July 25, 2015, 05:35:16 pm
content: 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-solarThey 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?

author: tom66
author_rank: Super Contributor
timestamp: July 25, 2015, 06:16:21 pm
content: iPhone 6 (non-plus) battery capacity 1810mAh @ 3.8V = 6.87WhSolar surface area ~2 iPhone 6 = 2 x 67mm x 138mm = solar area of ~0.018m^2Earth peak insolation = ~1400W/m^2This will generate 25.2W with a 100% efficient solar panelAssuming 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 nottoobad.

author: electr_peter
author_rank: Unknown
timestamp: July 25, 2015, 06:19:06 pm
content: 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.

author: edy
author_rank: Super Contributor
timestamp: July 25, 2015, 06:21:07 pm
content: 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_7w9sYCFQIIaQodWdIGlQI 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+12vIt'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.

author: amyk
author_rank: Super Contributor
timestamp: July 26, 2015, 12:01:57 pm
content: More like the world's thinnest and lightestand most fragilesolar charger... those PV panels don't look flexible to me.Does anyone else notice something amiss here?QuoteQuote

author: hayatepilot
author_rank: Frequent Contributor
timestamp: July 27, 2015, 06:16:06 pm
content: Quote from: amyk on July 26, 2015, 12:01:57 pmThis 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.

author: sunnyhighway
author_rank: Frequent Contributor
timestamp: July 28, 2015, 04:56:34 am
content: Quote from: hayatepilot on July 27, 2015, 06:16:06 pmDoes 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

author: miguelvp
author_rank: Super Contributor
timestamp: July 28, 2015, 04:17:50 pm
content: Quote from: mojo-chan on July 28, 2015, 03:29:04 pmSo 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:https://www.kickstarter.com/projects/159052311/solarade-smart-and-powerful-solar-charger/descriptionAlso what are the bullshit claim? are you doubting they can make a 2.5W panel that is 9 cm x 19 cm?Their first kickstater got them just about $70K and I guess their customers are happy enough to back them for this second one and probably told all their friends.Btw you can buy their 1st product athttp://www.amazon.com/Solarade-Worlds-Smallest-Portable-Charger/dp/B00T2UKA18and the actual panels for that one came from ixys which I guess also has rights to sell the solarade.I bet this time they probably got a more favorable contract.

author: suicidaleggroll
author_rank: Super Contributor
timestamp: July 28, 2015, 09:17:56 pm
content: Quote from: mojo-chan on July 28, 2015, 03:29:04 pmWhat claims are you saying are BS? I don't see anything unreasonable in their description.

author: suicidaleggroll
author_rank: Super Contributor
timestamp: July 29, 2015, 02:02:15 pm
content: Quote from: mojo-chan on July 29, 2015, 10:05:06 amThey later go on to clarify:"In bright sunlight, the 5 watt charger can fully charge an iPhone 6 in about 2.5 hours, which is similar to a wall charger."The iPhone 6 has a 6.9 Wh battery, not 9.5 (BTW - what phone on earth has a 9.5 Wh battery? Unless by "premium phone" you mean one of those ridiculous phablet things...). Under ideal conditions that could charge it in 1.5 hours. 2.5 hours is perfectly reasonable once you take into account idle current draw and inefficiencies.Quote from: mojo-chan on July 29, 2015, 10:05:06 amThey are being honest about the capabilities. Under good conditions it can output 5W, that's the same as a 1A wall charger, which many phones come with. It's not any more complicated than that. A 1A charger can certainly charge my phone in under 2.5 hours, as long as their 5w panel can actually do 5w under ideal conditions, I see no problem with their claims.Quote from: mojo-chan on July 29, 2015, 10:05:06 amWho ever said this was the ideal solar phone charger??? They didn't and nobody here did, except you. You're just nitpicking now...

author: tom66
author_rank: Super Contributor
timestamp: July 30, 2015, 10:06:26 am
content: Quote from: mojo-chan on July 30, 2015, 08:47:33 am85-90% is achievable.Quote from: suicidaleggroll on July 29, 2015, 02:02:15 pmiPhone 6 Plus has that kind of battery (larger screen) - around 10.7WhMaybe it could be called a phablet but it's a little small, only 5.5" screen.

author: suicidaleggroll
author_rank: Super Contributor
timestamp: July 30, 2015, 03:13:14 pm
content: lol, you guys crack me upQuote from: mojo-chan on July 30, 2015, 08:47:33 amQuote from: tom66 on July 30, 2015, 10:06:26 amMaybe if you're a gorilla...the iPhone 6 Plus is absolutely a phablet and is ridiculous looking, just like the Android phablets that are the same size or larger. I literally burst out laughing every time I'm walking down the street and see somebody fumbling with one of them or actually trying to hold it up to their face to use it like a phone. It's the best part of my day.But back on topic...Quote from: mojo-chan on July 30, 2015, 08:47:33 amAgain, nitpicking. 5W, 4.5W, it doesn't really matter, it is still a perfectly reasonable claim that it could charge the phone that they clearly specified in their ad (an iPhone 6) in under 2.5 hours with good sun, so I still don't see where you get these "scam" and "false advertising" claims.

author: tom66
author_rank: Super Contributor
timestamp: July 30, 2015, 04:43:57 pm
content: I laughed at 5 inch phones, having a 4.3" Galaxy S2 before... But to be honest I'm quite liking the S4 I have, with the big screen it's ideal for web browsing and pictures (which is 95% of what my phone use is)

author: Mechanical Menace
author_rank: Super Contributor
timestamp: July 30, 2015, 05:22:05 pm
content: Quote from: suicidaleggroll on July 30, 2015, 03:13:14 pmThe iPhone 6+ and S5 are about the average, and apart from iPhones* that size has been around the average since about 2011. They definitely aren't phablets. Both are smaller than my hands and both seem to be the perfect compromise between compactness and ergonomics. My avatar aside I'm not actually a gorilla but am personally glad phones started getting back up to reasonable, human usable sizes.*Though I'll admit iDevices have always being more high fashion than high end.

author: abebarker
author_rank: Contributor
timestamp: August 01, 2015, 07:43:43 am
content: It looks nice and thin. I've been getting ready for backpacking and it would be great to shed a few pounds. It sound like these guys are going to be using the new SunPower monocrystalline silicon solar cells. They are the only cells that I know of that are semi-ridged. They can be bent up to 30 degrees of an arc with out damage. The problem I see with this and every other solar charger is the lack of MPPT.I bought the X-DRAGON "20W" Solar Charger.http://www.amazon.com/X-DRAGON-Efficency-Technology-Smartphones-Foldable/dp/B00NGKPX4Y/ref=pd_sim_107_20?ie=UTF8&refRID=1Z1WW74TTV33SJ7MKB8A20W in quotation marks because it is not capable of outputting 20W for at least three different reasons. 20W is the theoretical maximum that could be generated by these cells. The cells are the SunPower monocrystalline silicon and they are the best on the market for monocrystalline silicon. You will not find better silicon cells than SunPowers cells, any where. This X-DRAGON charger is the best charger I have seen for the money.Unfortunately, I has one major flaw that it shares with every other portable charger I have seen; It has no MPPT circuitry. It has the best solar cells in the world and they are not allowed to operate at their best.It should be unthinkable to sell a portable solar charger without, at least, one MPPT circuit. Preferably there should be one MPPT circuit for each cell. It could only take a single cm² to hold a small inductor that could handle up to an Amp, a small shunt, a couple of caps and a package containing a buck-boost bridge and microcontroller.

author: edy
author_rank: Super Contributor
timestamp: August 30, 2015, 04:26:30 am
content: Wow....$1,021,583pledged of $50,000 goalYes, that is 2000% funded!!!

author: Psi
author_rank: Super Contributor
timestamp: August 30, 2015, 04:34:25 am
content: 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 sunThings 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.

author: suicidaleggroll
author_rank: Super Contributor
timestamp: August 31, 2015, 03:22:25 pm
content: Quote from: Psi on August 30, 2015, 04:34:25 am"double size" is the standard size. From the campaign:QuoteSo 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.

author: edy
author_rank: Super Contributor
timestamp: September 05, 2015, 02:19:09 am
content: 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/descriptionIt houses a 6000 mAh battery. Look what the campaign description says about the 18650 battery.....