1.Question:Can you connect an inverter to this ?
Answer:think the question was asked to learn about the system,inverter would not be necessary due to the lack of power being converted to ac
2.Question:How long does it take to charge?
Answer:there is no battery inside the panel, so the time it takes to charge your device is depending on the capacity of your device.
3.Question: When the charging process is interrupt by cloud or trees will the charging countinous automatically or must i plug out and plug in the smartphone?
Answer:If there is enough sun, it will supply power to your device. If it doesn't have enough sun it won't supply power. Answer to your question: it will resume charging automatically once conditions alot.
4.Question:Is it water resistant?
Answer:Yes.
5.Question:How long would it take to charge and iPhone?
Answer:with optimal sunlight, it will take about 2~3 hours.however, it's recommended to use battery bank to store power and use that to charge your phone.
6.Question:Is this thing flexible? Do I need to worry about it breaking when I put it inside a stuffed backpack? Or if I rest on my backpack with it inside?
Answer:No it's not flexible. But it's pretty rigid and the odds of it breaking is pretty slim.
7.Question:Is this 20 watts per port, or 10 watts each for a total of 20 between the two ports?
Answer:I can't seem to get much more than 5.04 volts x 1.71 amps = 8.62 watts per port while charging a large power bank. So, I think it is max 20 watts at peak efficiency, which is a substantial 5v load. Most USB devices are less than 2.5 amps @ 5 volts, I'm curious as to the device that would use 20 watts via usb?
Troubleshooting
1.This solar panel charger does not store power, you will need a power bank to store power or connecting to your device directly to charge.
2.This solar charger only charges your device when exposed to sunlight, it has no internal battery. It only takes pure solar energy and converts it to a current so you can charge your phone without a power source.
3.Not a battery. Does not hold its own charge.
4.21W refers to the power of the solar panel, which is not equal to the actual output power of the USB port, because there will be some loss in order to maintain voltage stability and safety of equipment during the charging.
5.The charging speed of this 21W solar charger depends on your devices, light intensity and cable used.