Since I published the first version of my foldable 5V solar panel, I came across larger epoxy solar panels (at about 6USD each on eBay) which measure 150x130mm and nominally deliver 500mA at 5V each (compared to the 150mA of the small 100x69mm panels used in the initial version). Also, these larger panels result in just about an ideal frame size that still comfortably fits on all standard 20x20cm printing beds.
The OpenScad source file is essentially the same as in the smaller version, since that was already fully parametrized and configurable. In addition of having the modified dimensions for the larger solar cells, the outer panels now also have loops which allow securing the solar panel somewhere, should that be needed. Given that a single solar cell delivers 2.5W, the 3-page version already delivers an output of 7.5W (which is 2x the power of the 5-page small version), I only provide STL files for 1-page (2.5W), 2-page (5W) and 3-page (7.5W) versions.
The solar cells of the 2- and 3-page versions are usually connected in parallel to deliver 1A resp. 1.5A at 5V, which is enough to charge about any 5V USB type device. However, it is also possible to wire the cells of 3-page version in series, which results in 500mA at 15V, just the right voltage to charge 12V lead-acid batteries.
As you can see in some of the photos, I even made one such 3-page solar panel which does balanced charging of 3S-type Li-Po batteries (3x3.7V = 11.1V) for a friend who wants to recharge the batteries of his quadcopter during his 2-week canoe trip through the Everglades. For this, I bring the 3 individual 5V wire pairs into the connector box and use a standard 3x2 right angle male pin header instead of the USB female connector. One cable for balanced charging then brings each of the 3 isolated 5V wire pairs is then attached to a easily available single 5V/1A Lithium charging module that a daisy chained at the output side and fed into a standard 3S XH 4-pin balancing socket. The other cable is for USB charging and just recombines the voltages of the three cells in parallel and ends in a USB charging connector.
I print my solar panels from 3mm ABS filament on my DIY Prusa i3, using a 0.4mm nozzle with 0.56mm extrusion width and 0.25 layer height. I print on a clear mirror without Kapton tape but thoroughly cleaned with acetone first and then with double concentrated lemon juice.
The solar panels are mounted by sliding them under the two triangular corner that are included in the frame structure. Then the panels are fixated with 2 of the separately printed triangles (the other 2 are spares), which are "glued" to the other 2 corners of the inner frame using acetone "slur" of the same color. This procedure is illustrated in the photos.
Two adjacent printed frames are attached via two M3x16 screws that serve as axes of the hinges and are secured with M3 nyloc nuts.
As for USB charging, I solder the USB female connector onto a little piece of striped prototyping PCB and insert it into the connector box. For charging with more than 500mA, I got the best results in connecting resistors to the D+ and D- USB signals as follows (see photo):
For the "Dupont" version of the connector box, I use a stanard 3x2pin right angle male pin header on a 0.6"x0.5" piece of prototype PCB. For the connecting cable, I use a 5x2 Dupont connector, cutting 2 corners off with a knife to obtain a 5+3pin connector which can only be inserted in the correct way, avoiding inserting it with the wrong polarity.