Anker B012YUJJM8 Anker 21W 2-Port USB Portable Solar Char (Open Box)

03/21/2020 Anker 21 Watt Solar Charger UPDATE. If you have an Android phone and would like to charge or top-up your cell phone's battery, please note: Android phones do not yet, to my knowledge, have a Solar Charging option. This means: Whenever there is an interruption from your power source, your Android phone will give an audible and / or haptic (vibration) alert, along with an on-screen alert. Each time this alert is caused, your Android phone is utilizing and tolling its on-board battery storage. The Anker solar charger will vary wildly depending upon sun position, cloud cover, shadow-fall and solar charger position. This means your power output can never be constant throughout the day. This also means if you aren't carefully monitoring your Android phone, you will end up with less of a battery charge than you started with - possibly down to a full battery drain. My experience with my Android phone: Direct, uninterrupted sunlight will successfully charge your phone, but that charge is offset by what other background tasks the phone is performing and whether or not it is currently being used and in the screen-on position. My advice: Either turn off your Android phone altogether, or task-kill any background programs as well as the phone's main screen to gain an appreciable charge from the Anker solar charger. The charger is rather slow, but it does work well in direct sunlight, even while charging more than one device simultaneously. Turning off your Android phone completely will ensure the best and quickest result. If the Anker solar charger is working at full capacity with bright sunlight, loosely wrap your Android device in a brightly colored cotton garment, like a t-shirt, so that the heat of the charging battery along with the heat from direct sunlight will not cause your Android phone to overheat and cease charging. The cotton garment will shield the Android device from the sun as well as wick heat away from the device, allowing the charging process to continue uninterruptedly. My experience in Virginia this week on sunny days proves that the Anker device works in optimal conditions with the correct precautions taken. Interestingly, Amazon's Kindle device has less software engineering and app processes, which means it charges more quickly using the Anker solar panel without the device working against itself if solar power is interrupted by shadows or cloud cover. Unfortunately, the Anker solar panel takes a very long time to completely charge a device. My Android phone and Kindle device took approximately 4 hours to charge simultaneously in bright sunlight. As stated, the Kindle required no finagling, whereas the Android phone required constant monitoring as well as certain safeguards to ensure that it was successfully charging in bright sunlight. The Anker solar panel is an intelligent and sound device - but its difficulty and price tag may far outweigh its utilitarian value for many users. Anker would do well to develop a solar charging option with phone companies so that once you connect the phone to the Anker charger and place it into "solar charge mode", your power will not be drained by ceaseless alerts whenever the inevitable cloud or shadow passes overhead. Since I own Anker power banks that have large capacities and take hours to charge from an A/C outlet, I will NOT attempt to confirm or deny that the Anker Solar charger will positively charge these power banks. My overall rating for this device remains a solid 3 out of 5 stars; I can honestly say that I am happy to own it, despite the effort required to have it work with my devices. - Chipper F. Xavier, Esq. ----------------------------- The Anker 21W Dual USB Solar Panel is an attractive, tri-fold, three panel device which charges cell phones when connected to your device and exposed to light - sunlight and ambient lighting will activate the solar panels. Unfortunately, the device cannot charge portable cell phone power banks. Additionally, cloud cover causes the unit to power down or cease to generate and deliver an electrical current, which triggers an alert on android phones. Enough of these no-charge alerts will cause your cell phone battery to totally deplete itself in a matter of an hour or two, which means the solar panel must be constantly monitored to ensure it is properly charging your mobile device. Since solar power is a great concept, I decided to keep the device, even though I should probably have returned it to Amazon. On bright, sunny days with no cloud cover, the device should work quite well. Also, placing it under a bright lamp would also cause it to deliver power - but if you're in close proximity to A/C or D/C, the device is rather unnecessary. This device is not yet ready for most real-world applications; thus I can give it only 3 out of 5 stars, despite its rugged and functional appearance. - Chipper F. Xavier, Esq.