FlexSolar 40W Foldable Solar Panel Charger with USB-C and USB-A Outputs for Phones, Power Banks, Tablets - Waterproof for Camping, Hiking, Backpacking

I've tested several portable solar panels in rugged conditions, and the FlexSolar 40W is a game-changer, but only when paired with the right battery. Let's break it down:Renogy E.Flex 10W:Ultralight (11.5 oz), but underwhelming: 0.696 watts/oz.Struggled to charge a 5000mAh battery in Yellowstone, even with optimal sun.Frustrating for demanding use.BigBlue 3:Moderate weight (24 oz), better output: 1.042 watts/oz.More reliable, even in cloudy conditions.Still struggled with heavy iPhone recording use.I feel the panel could be lighter with fabric trim reductions.FlexSolar 40W:Heavier (28.16 oz), but powerful: 1.243 watts/oz.The difference maker, but only when paired with a supporting battery pack.Key Insight:Solar panel wattage per ounce is important when you have to carry it on your back or in your boat all day, but compatible battery bank management is paramount.I have found optimal use occurs with a battery that allows for higher throughput charging. An unnamed Battery bank, that allows for 12V @ 1.5A input, allows for very quick recharge times.Avoid Anker battery packs that lack high-throughput charging.Best Battery Pack for Solar: https://www.amazon.com/dp/B0CJC57PPC?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_4&th=1Real-World Performance:With the correct battery, the FlexSolar 40W effortlessly powered a GoPro, multiple batteries, iPhone, iWatch, GPS/satcomm, speaker, headlamp, and more.Even in three days of limited sun, it maintained essential device power.In ideal conditions charging speeds are very impressive.Verdict:For serious outdoor users, the FlexSolar 40W delivers exceptional power and reliability.Yes, it's heavier, but the performance is worth it.Make sure to pair this panel with a battery that can take full advantage of the power output.Finally, use a HIGH QUALITY charging cable on USB-C. No more than 36" long. Look for something like the Anker USB-A > USB-C Powerline II, which uses a lower gauge wire. If you use a cheaper lighter weight charging cable, you are choking the solar panels ability to push power to the battery BMS.Links:*BEST* Unnamed Battery: [https://www.amazon.com/dp/B0CJC57PPC?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_4&th=1]*WORST* Anker Battery: [https://www.amazon.com/dp/B07S829LBX?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_10&th=1]*BEST* Flex solar panel: [https://www.amazon.com/dp/B09H6GGK55?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_2]*MID* Big Blue 3 panel: [https://www.amazon.com/dp/B01EXWCPLC?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_4]*WORST* Renogy E.Flex panel: [https://www.amazon.com/dp/B01K63CO0O?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_6]*BEST* Charging Cable: [https://www.amazon.com/Anker-Powerline-Certified-Samsung-MacBook/dp/B07213D35X?ref_=ast_sto_dp]

I tested the charger by putting it on my floor, with the glass windows closed. It was early afternoon, so the sun was at a high angle, but not 90 degrees to the solar panels. So the light was coming through glass with a reflective coating, and it was not coming in at the best angle. Even under these less than optimal conditions the panels were producing enough watts to charge my phone. I got it in case of an extended power outage in an emergency, so the solar cell charger is sturdy enough for my needs.

I'm on a 2-month wilderness trail trek. I use this to keep a 20k MaH battery charged, and use that to recharge a number of crucial devices such as a UV light for water sterilization, headlamp, phone (GPS! Movies!), and a commercial vidcam. So far, in summer, and in mountains and desert, it's been painless and fairly quick to keep the battery charged, a few hours on a rest-in-camp day, and occasionally charge the devices themselves. The 15-watt rating seems honest, I had a Big Blue fabric-covered solar charger advertised as 21 watts that didn't charge things as well or as quickly, and unlike this one it wouldn't reset itself after a power fluctuation, so on cloudy days or with "dumb" or smaller-battery devices you often had to unplug everything and let the panel reset. Plus that fabric, and the joints between them, became worn pretty quickly and the fabric tore, sometimes even exposing wiring, and loose "hinges" (just folds, really) made positioning it and standing it up for use a real pain.This has no fabric, and no raised rims to the solar cells, it's entirely laminated, with shiny transparent plastic on the cell side making it a single surface, and the other side is a hard, durable dark and textured material. It is a tremendous leap forward, but be careful, even that protective plastic can get scratches, or clouded by cleaning solvents.The only real problem is the anchoring points you would use to hang it from a backpack are just holes in the corners, leaving a thin strip of material as the only support, and they become easily deformed when they're actually used for their ostensible purpose, and I have stopped hanging it from them for fear of tearing. The "hinges" between panels are the same, thin strips of the base material. So far they remain okay, sufficiently stiff to maintain all three panels in approximately the same plane but it's an obvious possible failure point.The USB housing is solid, and durably anchored to the hard material on the back. The controls are simple-- a red light on one side of the USB socket indicates a good sunlight exposure, and a green light on the other side indicates a solid connection with whatever you're charging. If the connection is so-so that light is blue, and if the device is not connected properly it stays dark (or if it's an old-fashioned "dumb" device like my headlamp. Check the the thing itself that you're charging, it might still be getting current).Overall I would give this a high "good " rating but not excellent. There are cheaper panels, much lighter panels, more durable panels, and more productive panels. BUT IT'S IMPOSSIBLE TO GET TOO MANY OF THOSE CHARACTERISTICS AT ONCE, and this directly hits "the sweet spot" on some things, comes close on others, and IS NOT SUPER EXPENSIVE. In car terms, this is not a Rolls or a Maserati, but it is definitely a good solid Chevy or a Toyota. It may not be expedition-level durable, as I can already see a little bit of wear from daily use, but it's certainly good for the occasional trip to the beach or for the family to take to the mountains on a weekend, or for the emergency kit in the trunk of your car.Improvements? I would suggest looking at reinforcement of the strips between the panels, and eliminatethe holes in the corners for hanging it and imbed loops in the plastic instead, and think about rubber plugs to close the USB port to dust and moisture.But if this is the kind of thing you're looking for, this one definitely gets very high marks. Not the absolute highest, but it's also inexpensive.For purposes like mine I believe it is a consumable item that will have to be replaced regularly, but for most people it would be durable goods. Personally? I'dsay if you're in the market for this kind of thing, buy THIS one.