BigBlue Portable Solar Charger 28W with Digital Ammeter,25.4% High-Efficiency, USB-A/USB-C Ports, Folding Waterproof Solar Panels with Carabiners for Camping, Backpacking, Phones, Tablets, Power Bank

It’s solid. On the bright sunlight it charges two devices with 2.3-2.4 amps. Good enough to recharge two 10000 mah power banks within several hours. We took it to Yosemite and it did the job. I didn’t take it on the hike, not sure it would work well when attached to the backpack - the angle of the sunlight wouldn’t be good. Works perfectly if you leave it in the camp though. While we were hiking it was completely recharging our power banks.The main con is that if one of the panels is in the shade, the charging is closed to zero. The second one is that the pocket for the device is not insulated and, well, it’s black. So if you put your smartphone there, it will be overheated within a few minutes and will stop charging. At first I think it didn’t work properly though, so here a few tips that I’ve figured:1. All the panels must be exposed to the sunlight. Even a small shade on the panels affects efficacy dramatically.2. It’s better to use with powerbanks rather than charge your phones/tablets/whatever directly.3. Whichever device you are charging, keep it off the sun. The pocket on the solar panel itself doesn’t work at all, and if your device has any overheat protection, it will stop charging pretty soon. If it doesn’t have a protection, it can just explode if the sun brights really hot. I was putting the solar panel on a camping chair with insulated pocket for a cold drinks and putting my power banks in the pocket. Works pretty well.4. If the sunlight is good, there is no need to try to sustain the good angle (the closer sun rays fall to 90 degrees, the more power the panel will generate). But if it’s not very sunny, try to put something under the panel to keep it directed towards the sun.With that, I think it’s a pretty good solar panel, if you know the above and understand how to use it.Be safe outdoors!

I love this charger (BigBlue 5V 28W with readout) I use this to charge multiple battery packs and it is wonderful. I have charged my phone off of this all year so far. I bought a usb multi meter to check voltage. The voltage is regulated well and I have never seen it go above 5.1V. The lowest voltage I have seen on a cloudy day was 4.9, still well within range to charge my battery pack. I live in AZ and get plenty of sun. My battery packs are always charging at max input because this charger has so much power available. I built a stand which I set the solar charger on. The stand can change angles so it can be aimed for the best angle. I have used this to go camping and never needed to plug into the grid to power anything within my camp site. I truly can’t say enough good things about this charger.1 year update. 12/27/18Still as strong as the first day I received it. The fabric has faded however, that’s to be expected with as much use as this gets. The Arizona sun is relentless and will fade any fabric. I have used this solar charger to run all of my USB devices and I only need to use it every few days when paired with a proper battery bank. I am now using this charger to charge a ~26,000 ma battery bank (Anker). I charge at 4A and the pack is charged fully within 6-7 hours. This battery lasts my Wife and I 5 full days with both of our phones (3 year old iPhones) from dead to full charge. Even in December, I am able to pull 3.9 A at about 11:00 AM. If you are looking for a great product to help get away from the grid for any reason. This is what you will want. It has plenty of power to charge almost anything USB you can think of, especially when you pair it with a good storage bank.Update: 3/18/2023Still working great! I have used this hundreds of times by now. Even being over 5 years old, it still puts out 4 amps. My cords are the limiting factor. I still take this with us everywhere. When we’re camping, we never need to worry about our USB powered devices going dead. I always have this charging several battery banks to ensure we are good to go. We truly enjoy this solar panel and have recommended it several times over to friends and family.One thing to note, as with any fabric, the color will fade with the sun. So it does not look “pretty” and new any more, but I think of it as a battle scar and how many good times have been had because it sat out and baked in the sun!

Quick and convenient to set up, and it feels sturdy. It worked with my Ipad pro 9.7 inch- although I think the 'smart' circuit doesn't recognize it properly as it was only delivering 0.5 Amps to my IPAD pro, when it SHOULD be drawing the full 2.0 AMPS. Did eventually charge the IPAD though (you have to leave it in sleep mode to charge with that low voltage btw)I have only had it for a day and it seems to provide reasonable charging for 2 devices both in full sun and overcast skies. I did not get more that 1.2 AMPs total so far. but I suspect that this is more a problem of devices not interacting well with the 'smart charge circuit'.I bought this because of the Ammeter, it is great for knowing how well you are doing at charging a device at any given moment- but you cant read it in direct sunlight, you have to shade it with your hand.A couple things to keep in mind.:-It wont charge if any of the 4 panels are covered or not deployed.-DONT use the built in pocket to store the device you are charging. It gets hot in there as some genius decided to make the pocket black and heat damages lithium batteries.-Remember that some high draw devices will only charge if they are off.