jns Assuming a 20mm wide top and bottom edge plus a 10mm wide left and right edge, I get a gross solar input of 352.8 W using AM1.5 of 1000W per square meter. It would take a conversion efficiency of greater than 50% to have a 180W output for this panel. At 20% conversion, the output before conductor losses is about 70W. Using that assumption of 20%, if Vmp was 18.0v, Imp would be about 3.89A. So the answer is no, not on the Earth unless you used a solar concentrator which would heat the panel to excessively.

jns 30W may be the solar power input before conversion using the AM1.5 standard of 1000W per square meter. It is hard to tell since the dimensions are not given.

jns I do not use the auto position, so this is speculation. The manual says: "Only when the voltage is higher than 0.8V, this data will be shown on the display." The meter may be using a little circuit power when it is determining which measurement and range to use. This would be seen as less than tens of megohms of resistance at the leads and would be parallel to what you are testing. Thus some reduction of the voltage reading.

jns This panel looks to be about 25% of a square meter. At the AM 1.5 standard, it would have about 250 Watts of solar energy hitting it. At a conversion rate of 25% down to 15%, the output would be from a bit more than 60 Watts down to a bit less than 40 watts. After conversion circuit losses and wire losses, the true output would be less.

jns In the description, under Product Details, one picture is labeled "SD card slot Hidden design, flip the lens upward to get SD card slot and reset button". With your thumb, carefully move the lens upward to expose the card slot and reset button. Do not try to rotate sideways. Move downward to your desired vertical position when done (I just learned this, too).

jns Calculate the size compared to the AM 1.5 standard for a one square meter level surface which has 1000 watts of energy impinging on it. If I assume that the actual solar cells cover 0.5 meters by 0.25 meters, the energy impinging would be 125 Watts. Therefore I conclude that the 100 Watts is the total input energy at the AM 1.5 standard. The output energy after conversion and regulation is likely to be around 20 Watts if the cells have a high conversion rate. Rooftop solar panels are greater than one square meter and can get to 300 Watts if the cells have a high conversion rate.

jns The battery compartment says AAA 1.5V, so alkaline batteries work.

jns The ten connectors are: USB Mini-B, 2x Micro-USB, Nokia 2mm, Nokia 3.5mm, PSP 4mm, Apple 30 pin dock connector, LG sync for VX5400 and others, Samsung old 20 pin, Samsung new 20 pin (as best as I can see). Note that only the 5v and the ground return are sure to be wired on the connectors.