The USB-C output on the Solar Panel is rated to output max 5 Volt 3 Amps, which is 15 Watts. The USB-A output does 5V 2.4A which is 12 Watts, so it can charge two devices, 15W & 12W for a total of 27 Watts. What I'm understanding is it depends on what type of port, sometimes USB-C can supply 9V 3A (27 Watts), 15V 3A (45 Watts), etc.
This solar panel could supply 5v 3 A (15W) max from type c and 5v 2.4 A (12W) max from type a. That is all! Or 15+12 = 27 W from both ports. So you could get 15 w MAX from one port during ideal conditions. During charging power station you get lower number. And you get your 7-8 W. I didn't get why you waited up to 30 W for your power station in that situation.)
Only 5-7 Watts output from a 30W-Panel? Lol. That is poor! You should get 21W out of this at least! Or 5 * 3 = 15W! 7W only means 3 panels out of 4 are DAMAGED/not working! For comparison: I have a 28W-Panel from a chinese High-quality brand, which gets you ~25W on 18V (about 90% efficiency). Which is really good allready... This panel costed about 50 Euro for 28W output. This panel is poor in shadowing-conditions, but when sun shines bright and without shadows you get a good power out of it! As soon as the smallest shadow shines on it, you get only 5W output. And at half shadow you nearly get like 1-2W out of it, which is not good. And i have another cheaper panel which only has 24W max. And it gets you around 16-20W on 18V output (it has 24V btw). So it´s not a standard 18V- or 21V-panel like others are. But it has a GOOD shadowing-output! Even in half shadow you get 10W out of it! It consists of 8 panels. Each panels has 2 cells on it. So in total 16 cells. This 24W-Panel is a specialized boating-/yacht-highvoltage-panel which has 3 volts more output than others with same size. Which is extremely good since it means you can charge for a much longer time in the afternoon, when sun is going down and voltages sink! These two are currently my most-used small panels. They are really, really powerful! I can easily charge a small 220Wh Powerstation with that small 24W- panel in just 10 hours! Assuming of course it´s sunny enough! I have another 8 other panels of different sizes and brands, though (1x 8W, 1x 120W, 1x 18W, 1x 30W, and another 4 panels with each 30W-output). Some are replacement-panels that i only rarely use. And i have a big Panel with 120W as well (which is really, really bad at shadowing-conditions, which is why i currently don´t use it, as there is not enough sun currently in my country).
