Solar Panel, Anker 21W 2-Port USB Portable Solar Charger with Foldable Panel, PowerPort Solar for iPhone 11/Xs/XS Max/XR/X/8/7, iPad Pro/Air/Mini, Galaxy S9/S8/S7/S6, and More

I am not an expert when it comes to solar panels. I can only talk about my experiences with this product. As with all products I buy on Amazon I thoroughly check out all the reviews. Good and bad. I also check on YouTube to see if anyone has written a review on the product as well. First thing I notice in some of the reviews on Amazon was that people had a hard time charging the Anker 20100 mah power core with this solar panel. That is the power core I have and why I wanted to get the solar panel. I enjoy the outdoors and wanted a way to keep my power core changed and hence, all my toys that I have for hiking and camping. It seems clouds cause the 20100 power core to drop down to a trickle charge and stays there even if the sun comes back out. People had to unplug and plug it back in for it to resume a full charge. I kept reading the reviews and someone found that the Anker 26800 mah dual inport charge power core does not do this and will resume a full charge when the sun comes back out. I also checked the reviews of this solar panel out on YouTube which has several. There was one review that really sold this solar panel for me. It is called, “Anker vs ....”. I’m not going to put the other solar panels manufacturer here but I’m sure you will find it if you look. This guy really put these things through a lot more then anyone will ever do to them. The competitor’s solar panel only had two panels to the Anker’s three that I thought was a little unfair. Other then that, his test was fair across the board. He through them around and tossed them from a height of 20 feet. Left them out in a rain storm and through them both in a pond. He then lite a fire to dry them out that I was sure was going to melt them. He stomped on them and dropped a ten pound rock on each of the panels. His review is what sold me on this solar panel. So, I bought a the Anker 26800 power core and 21W solar panel together. I have not tested this panel out but two times. Both days were cloudy with some sun. Each time I angled the solar panel torward the sun to get the most of it and left it to charge the power core. The first day was more cloudy then the second. On the first day my power core was down to one light and I charged it for about 6 hours. It had three lights lite up at the end of the test which is a charge of 50 to 75 percent to the power core. The second time I charged my power core it was back down to one light again. This time there was a little more sun but over that time became more cloudy. I only charged it for 4 hours this time. See picture of clouds from the start of my second test. In this time it went from one light to two lights on my power core. The best I can figure is that is a 25 to 50 percent charge to the power core which only has 4 lights. So with the two tests done on cloudy days, as close as I can figure, that is an average of about 12 to 25 percent charge to my power core every two hours. I think that is pretty good but like I said before, I’m not an expert. I have two lights on now which is somewhere between 25 and 50 percent charge on the power core itself. I am waiting for an all sunny day to see if I can charge it up the rest of the way so the power core is fully charged. At which time all four lights should go out indicating the power core is fully charged. I will update this review when I have completed this last test. In all, I am very satisfied with this solar panel.Update-I just finished charging my Anker 26800 power core with the solar panel. It was a clear sunny day. I angled my solar panel torward the sun and started charging my power core at 8:30 in the morning. It had two out of four lights lite when I plugged it into the solar panel and the second light started flashing on my power core letting me it was charging. It took 6 1/2 hours for the power core to be fully charged. Over that time I adjusted the solar panel’s angle twice. As far as I can tell the power core charged anywhere from 50% to 75% in that time frame. That is still an average charge of about 25% every two hours. Not a big change from the two cloudy days before. This is a huge power core and I have not drained it in any less than 3 days. I charge my spotlight, headlamp and, my iPhone 5s from this power core. I have also run my two camp lights that are 100 lumens each overnight for about ten hours and they did not even use 25% of the charge from my power core. See picture of the things I have charged. I am very happy with how well this solar panel preformed. It does not seem to have any trouble charging my Anker 26800. I do not see myself running out of juice to power my toys on multi day hiking and camping trips. In order for that to happen, I would have to have no sun for 3 or 4 days. But, this solar panel seems to have the ability for a slight trickle charge on completely overcast days. I will try that next to see how well it works. I may have to limit my use of some things but I don’t see myself running out of power completely. This solar panel has preformed beyond my expectations and I am very happy with it. If I ever need more then one, this is the one I’m going to buy.

This is an outstanding, high power, reasonably compact solar panel that will charge any USB-chargeable device. Anker's "PowerIQ" system allows it to communicate with essentially all USB devices (e.g. Apple, Samsung, and other devices) to charge at the maximum safe rate supported by both the panel and the device (up to a per-port limit of 2.4A). Even "dumb" devices expecting a "dumb" USB charging standard-compliant charger that doesn't perform any communication will also work fine. I've tested it with 1 ampere and 2 ampere dummy loads and it will easily supply its specified power if it is correctly positioned. For a 21W nominal power output, it's remarkably compact, thin, and lightweight.Physically, it is divided into four foldable sections: three section have solar panels (there are metal grommets in the far corners of the solar panel-containing sections), while the fourth section has a small velcro-closed pocket containing the charger electronics and two USB ports in a small plastic housing. The strip of velcro used to close this pocket is small, and will not retain a phone well if the PowerPort Solar is moving (e.g. strapped to a backpack). Either add more velcro yourself, or use a cable to connect to your device inside the backpack. Keeping your phone or other device out of the sun (or the enclosed pocket) is probably a very good idea, as the panel and the pocket get quite warm in the sun and your device may overheat and turn off -- keep the PowerPort Solar in the sun run a cable to your device in the shade (Anker PowerLine cables work very well, particularly at high charging currents.).Build quality of the PowerPort Solar is excellent, with good stitching, high quality grommets, SunPower solar cells for greater efficiency, etc. My only suggestion would be to use a full-length zipper instead of the short piece of velcro to secure the pocket.Like all solar panels, it is extremely sensitive to its positioning relative to the sun: on a bright, clear sunny summer afternoon at ~46 degrees north latitude it provided 2A at 5.05V from one port into a 2.5 ohm dummy load when angled to be perpendicular to incoming light. A modest change in angle (say 20-43 degrees) results in voltage and current dropping to 4.8V and 800mA, respectively, with the same load. Similarly, small changes to incoming light (e.g. a light haze in the sky, or a cloud passing in front of the sun) will notably reduce the amount of power it can provide.I've found that it will charge my Motorola MotoG3 phone (the phone has an internally-limited maximum charging current of 1A) at the phone's maximum charging rate in moderate conditions (e.g. partly to mostly cloudy) with no problems, but your mileage may vary. Many devices have "smart" charge controllers that will automatically cut back on charging current if the supply voltage drops (e.g. a cloud briefly passes in front of the sun), then attempt to increase the current again if the supply voltage increases. Such devices are well-suited for this panel and will charge well.Some smartphones or tablets will light up their screen for a few seconds when they are first connected to a charger. In marginal conditions, like late afternoon, the PowerPort Solar's output is insufficient to charge the phone continuously and it will send short pulses of power. While not harmful to either the PowerPort Solar or the phone, the phone will interpret these pulses as it being repeatedly connected and disconnected from a charger. This causes the screen to light up, turn off, light up, turn off, etc. and generally waste more power than the trickle you'll get from the PowerPort Solar. In short, use the PowerPort Solar with confidence when the sun is bright and directly falling on the panels, but stop using it when conditions get marginal.Some devices, like the Anker PowerCore 20100 power bank, will reduce the charging current if the supply voltage drops and will remain at that lower current level until they're manually disconnected and reconnected. This makes it very impractical to use such products with the panel, as a single cloud can dramatically increase the time needed to charge the device. If you want to use this panel with a power bank (which is generally a good idea, as you could charge the power bank during the day with the panel strapped to a backpack or something, then use it to charge your devices at night), make sure the power bank will automatically recover from brief voltage drops and will attempt to increase the charging current again. The PowerCore 20100 doesn't recover from such situations without being disconnected, though I've raised the issue with Anker and they're looking into improving things for future models. Since power banks don't have screens like phones or tablets, they avoid the on/off screen issue described above, and are likely a better choice to charge in marginal conditions, assuming they recover from voltage dips.The two photos I've included are of the PowerPort Solar resting against my backpack outside on a sunny day, and the display of a generic PowerJive USB volt/ammeter: you can see that the panels are providing exactly 5.00V at that moment (the voltage typically varied between 4.8 and 5.1V) and 1.97A of current and that the panels had charged my PowerCore 20100 with 737mAh so far. Both photos were taken during my lunch break.In short: if you're willing to accept the shortcomings common to all solar panels (e.g. sensitive to angle relative to the sun, sensitive to clouds, haze, and marginal conditions, etc.), the PowerPort Solar is an excellent choice and I highly recommend it.