Eugene trya power bank with long USB cable on a sunny day. (if possible, do you have a USB power meter, those dongles that show the volts and amps that goes to the powerbank)

Eugene ifthere is alot of shade or clouds it will only show lower voltages. If it is full sun it will go upto 19volts in the DC port.. and upto 5.4volts on USB output (you can use a USB dongle power meter for Volts and amps to a powerbank with a USB cable)

Eugene atrue MPPT would still output 14 volts but the Amps will go higher than rated on panel. (say panel can push 5amps @ 19v for a 100w. it will go 14.4v but @ 6.5amps) vs PWM will go 14.4 * 5amps at max which is a mere 72watts out of a 100watt solar panel.

Eugene Check for marks or small dents or fused line or blemish on panel surface. It should all be the same. No dark little spots like yours has. Lines should be silver not dark

Eugene whatis not as expected?

Eugene Putthe solar panel in full sun (that area is not full sun, there is shades or semi-shade area falling over panel) Angle of panel must be 20-35degree's angled towards the sun. depending on your area. You can google best solar direction your area. Some area's have 30-45degree angle to South or West. In South Africa it is 20degree's to 35degree's North Facing

Eugene Mytests also showed around the 32watt or 40watt (i was testing on a day of 18-19degree's Celsius) Only thing to watch out for, is if you connect 3 or more in parallel (as now the amps is climbing/increasing). In series the volts go up, in Parallel the amps go up. If your using it on a MPPT like yours then you can add quite a few. Just have to watch out as the cable thickness going above 4amps will need to be more than the current cables given with solar panels. (4panels would push 8amp -. So then a 10gage or 8gage wire would be needed over 30feet range) You can only series 2 of those panels as your MPPT is limited to 50volt (23 23v). MPPT's like higher voltage but don't go over maximum.

Eugene Overtime it will affect or just stop working (specially cause it's a flexible product). It might work fine for a few months but that is a very direct bend over the electric circuits. The one with the fold ontop next to the carabiner opening should not affect performance but it's also not a nice thing to see, i'm not sure what the elements might do there either. As if it would get wet or mist or rain. I might get problematic. best to check with banggood.

Eugene Did you buy the 25w or 50watt version? if the battery is half-drained. How many watts do you get on the Imars solar panel in full sun? How many volts and amps does it push to battery to charge it full , from 50% drained battery ? thanks

Eugene Canyou check the output via a watt meter? or amp meter?

Eugene Didyou test it on a powerbank? what output does it jump to? How many mah battery capacity does it charge in 1hour - in full sun.

Eugene Reasonfor top front mount. is if you want to mount it onto a flat surface or an RV. Then you cannot have the charging block or usb ports at bottom of panel. You to mount it to the roof or to a mount that is flat.

Eugene Measurein direct sunlight with a Phone that uses USB to TypeC (type C cellphones draw more power) There are apps you can download from playstore to see charger or battery status. (shows the voltage and charging rate)

Eugene correct, i would rate it around the 15watt mark. 5v x 3amps maximum. is 15watt. more realistic you will see 2.1 or 2.4amps at 5v